II IVNOIIVN INI3I0IW JO AIV11I1 IVNOIIVN 1NI3I03W JO tlVllll IVNOIIVN I N I 3 I Q 1 W JO UVlin y • V >F MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF i \>\ i >v i xA j ^^ I \/\ i j* II IVNOIIVN 1NI3I03W JO *l»ll!l IVNOIIVN 3NI3I03W JO A I V 11 11 IVNOIIVN 3 N I D I 0 3 W JO A I V « I I 1 NE NATIONAL LIBRARY OF MED,CINE N A T I 0 N A L I I . R A « Y O F M E D I C I N E N A T I O N A I I I B R A R Y O F M E D I C I N . NE NATIONAL LIBRARY OF MEDICINI NATIONAL LIBRARY OF MEDICINI NATIONAL LIBRARY OF MEDICINE i /V1 vn iNiaiaiw jo Aavaan ivnoiivn ini:ioiw jo Aavaan ivnoiivn jn i 3 i a iw jo auvbb n ivnoiivn INE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINI O p / NO \ 5rS ■' A TEXT-BOOK DISEASES OF THE EYE HENRY D. NOYES, A.M., M.D. Professor of Ophthalmology and Otology in Bellevue Hospital Medical College; Executive Surgeon to the New York Eye and Ear Infirmary; recently President of the American Ophthalmological Society; Member of the New York Ophthalmological Society; recently Vice- President of the New York Academy of Medicine; Permanent Member of the New York State Medical Society; Member of the American Medical Association, etc., etc. jgjecotxd and Revised ISdition ILLUSTRATED BY 5 CHROMO-LITHOGRAPHIC PLATES, IO PLATES IN BLACK AND COLORS, AND 269 WOOD-ENGRAVINGS NEW YORK WILLIAM WOOD & COMPANY 1894 NWt Copyrighted, 1894 WILLIAM WOOD & COMPANY PRESS OF THE PUBLISHERS' PRINTING COMPANY 132-138 W. FOURTEENTH 8T. NEW YORK EBRATA. Page 651, for Plate III. read Plate A. Page 656, Fig. 245, for Bouillaud-Beoca read Bouillaud-Broca. PREFACE TO SECOND EDITION. In revising this treatise numerous additions have been made to render it more complete. For example, those parts of cerebral anatomy and pathology which have a bearing upon the eye have been discussed at unusual length for such a work; this is true both for the motor nerves and for the optic nerves. Some chap- ters have been considerably modified and some have been rewrit- ten; for example, those on granular conjunctivitis, asthenopia, sympathetic ophthalmia, glaucoma, cataract, hemianopsia, etc. Throughout the book the attempt has been made to set forth the most recent and well-established views in ophthalmology, and references to authorities have been abundantly inserted that readers may be aided in further research. The writer's judgment on new suggestions has been freely given on points where he has opinions. He is indebted to his friend, Dr. John E. Weeks, for the pathological statements respecting so-called Bright's retinitis and for his drawings which illustrate it. For preparation of the index he again acknowledges with thanks the painstaking work of Dr. D. W. Hunter. Additional cuts and plates have been inserted, and attention is called to the list on p. xiii. The author has been much gratified by the kind reception which his work has met, and has for this reason sought in this edition to make it still more worthy of acceptance. PREFACE TO THE FIRST EDITION. The present work has grown out of a treatise on diseases of the eye, published in December, 1881, in Wood's Library of Standard Medical Authors. The same arrangement of subjects is adhered to: presenting in the first part the general anatomy and physi- ology of the eye with its functional disorders, and in the second part its inflammations and organic textural changes, and the lesions of the accessory parts. That this order is both scientific and natural seems evident. The spirit of the book is clinical, but an adequate preparation for clinical and practical work demands a wide range of preliminary knowledge. This is true of all branches of medicine. To the study and experience needed in general medi- cine, must be added for proper treatment of troubles of the eye, a considerable acquaintance with physics, mathematics, and physio- logical optics. The knowledge which they furnish finds its chief application in unravelling functional disorders of sight, viz., errors of refraction and accommodation, and motility. These subjects as well as the operative surgery of the eye will always constitute a field of special practice. But in dealing with pathological conditions or inflamma- tions, the physician must take his share with the ophthalmologist. Nor can he refuse to take in hand the ophthalmoscope, because it is not only essential to discovery of deep lesions of the organ, but its revelations often have an important bearing upon remote pathological conditions. In accordance with the practical intent of the book, mathematical formulae have been omitted; pathology and microscopic anatomy have been presented so far as seemed helpful to an intelligent ac- count of morbid processes; the share which micro-organisms have in exciting diseases of the eye, has been fully recognized; no little labor has been spent in setting forth its intimate relations to the VI PREFACE. brain and nervous system, as both illustrations and descriptions testify; the participation of the eye in numerous general diseases or lesions, of remote organs, such as the kidneys, the uterus, the heart, etc., and the reflex influence which the eye can sometimes exert upon distant parts have been set forth. The writer has quoted his own cases and experiences, and stated his own opinions; he has familiarized himself with the work of others, not only in their writings, but pretty largely by personal acquaintance, and drawn freely upon their labors, as may be seen by the references in the text, and by the bibliography. Of the illustrations manj^ are familiar, while not a few have either not hitherto appeared in ophthalmic text-books, or are orig- inal. In depicting diseases of the fundus oculi, black and white have been used for many of the ordinary lesions, while colored plates have been reserved for special conditions, some of which are familiar and others unusual. The liberality of the publishers in the number and quality of the illustrations has been a source of gratification and will be ap- preciated. For the compilation of the copious indices acknowledgment is due to the author's friend, Dr. D. W. Hunter. In them references will be found to passages where the connection of general diseases with eye pathology is mentioned, and one will need only to look under the head of such diseases for the ocular complication. To the medical profession, who have greatly honored him with their confidence, and to the classes of Bellevue Hospital Medical College whom he has taught and who have rewarded his efforts by their attention and respect, the author offers this volume as an attempt to discharge a great debt. CONTEXTS. PART FIRST. CHAPTER I. GENERAL ANATOMY OP THE GLOBE. PAGE Measurements—Component Structures—Vessels of the Globe and their Relations to the Diagnosis of Diseases of the Eye, . . 1-i) CHAPTER II. GENERAL PHYSIOLOGY OF THE EYE. Refraction: Cardinal Points—Optic Axis : Visual Line: Line of Fixation : Angle Alpha : Angle Gamma—Accommodation— Functions of the Retina: Blind Spot—Visual Acuity—Form Sense — Test Types — Visual Field: Perimeters: Eccentric Vision — Color Sense — Daltonism: Color Blindness — Light Sense : Photometer of Forster : Phosphenes : Vascular Image of Purkinje—Visual Purple,........10-34 CHAPTER III. HOW TO EXAMINE THE EYE. External Inspection—Oblique Illumination—Tension—Mobility— Ana'sthetics—Functional Examination,.....35-38 CHAPTER IV. THE OPHTHALMOSCOPE. Instruments, their Principles and Varieties—The Fundus Oculi in Health,............39"52 CHAPTER V. GLASSES. Spherical: Cylindric : Toric—Arrangement and Nomenclature— Dioptries: Prisms,..........53-60 CHAPTER VI. ACCOMMODATION AND ITS ERRORS. Presbyopia-Second Sight—Spasm—Paralysis and Paresis, . 01-68 Vlll CONTENTS. CHAPTER VII. ERRORS OF REFRACTION. PAGE: Ametropia, viz.: Hypermetropia, Myopia, Astigmatism—Diagnosis of Refractive Errors—Subjective and Objective Methods— Mydriatics—Ophthalmoscopic Optometry—Schmidt- Riinpler's Method—Shadow Test—Thomson's Method. Hypermetropia: Anatomical Characteristics : Symptoms : Complications : Diag- " nosis : Prognosis : Treatment: Length of Axis in H. Myopia: Length of Axis in M.: Causes—Functional Disturbances and Pathological Anatomy—Prognosis : Diagnosis : Prophylaxis : Treatment. Astigmatism: Definition : Varieties : Symptoms : Dr. Thomas Young: Stokes' Lens : Diagnosis by Ophthalmo- scope—by Shadow Test—by Ophthalmometer of Javal and Schiotz : Disc of Placido—Anisometropia—Incidental Effects of Glasses,............69-131 CHAPTER VIII. BINOCULAR VISION. Anatomy and Physiology of Ocular Muscles—Horopter—Homony- mous and Heteronymous Images : Paralysis of Muscles : Symp- toms : Diagnosis—Special Paralyses—Etiology : Origin of Nerves animating Ocular Muscles: their Nuclei—Basal, Nuclear, Orbital, Cortical Paralysis—Prognosis—Treatment— Prisms, Tenotomy, Advancement—the Oculo-orbital Fascia— Congenital Paralysis—Spasm of Muscles—Nystagmus—Con- jugate Deviation,..........132-176- CHAPTER IX. STRABISMUS CONCOMITANS. Varieties—Measurement—Etiology—Amblyopia—Course—Cause of Strabismus—Treatment: Atropine, Eserine, Glasses, Opera- tion : its Mechanism and Ultimate Result—Strabismus deorsum vergens, and sursum vergens,........177-196 CHAPTER X. ASTHENOPIA. Accommodative—Properties and Uses of Prisms—Muscular—the Metre-angle, how Measured, its Relation to Prisms—Adduction and Abduction—General Divisions and Considerations—Sub- jective Symptoms : Objective Symptoms—Tests by Prisms— The Prism Carrier—Perimetric Examination—Retinal Anaes- thesia—Nasal Disorders—Treatment—Prisms—Operations, . 197-230 PART SECOND. CHAPTER I. GENERAL CONSIDERATIONS. General Treatment—Shades—Protective Glasses—Bandages—Asep- sis : Antisepsis—Anaesthetics : Cocaine—Instruments—Mydri- atics : Myotics—Collyria—Means of Reducing Tension, . 231. CONTENTS. IX CHAPTER II. THE EYELIDS AND CONJUNCTIVA. Anatomy—Blephariti s m arginali s—Hordeolum—Chalazion—Phleg- mon— Tarsitis—Eczema—Xanthelasma—Molluscum contagio- sum—Herpes zoster Ophthalmicus — Epithelioma, Lupoid— Naevi—Diseases of Eyelashes—Entropium—Ectropium—Bleph- aroplasty — Blepharophimosis — Cantholysis— Canthoplasty— Tarsoraphy—Injuries and Lacerations—Coloboma—Epicanthus —Spasm of Orbicularis—Paralysis of Orbicularis—Ptosis— Burns—Symblepharon—Ankyloblepharon, .... 247-291 CHAPTER III. THE LACHRYMAL APPARATUS. Anatomy—Diseases of Lachrymal Gland—Dacryocystitis—Chronic —Acute—Lachrymal Fistula—Leptothrix lachrymalis, . . 292-307 CHAPTER IV. THE CONJUNCTIVA. Anatomy and Physiology—Conjunctivitis— Hypersemia Palpebralis —Conjunctivitis Simplex, Catarrhalis, Symptomatic, Meta- static, Catarrho-rheumatic—Purulenta, Neonatorum, Gonor- rhoea—Plastica : Croupous—Diphtheritic, Acute and Chronic —Granulosa : Trachoma — Papillary—Follicularis—Treatment —Xeroma—Sequelae—Morbid Growths: Vernal Catarrh—Phlyc- tenule : Herpes: Pemphigus; Traumatic Conjunctivitis— Ecchymosis—Pterygium,.........308-370 CHAPTER V. THE CORNEA. Anatomy—Physiology—Pathology—Keratitis : Phlyctenula : Her- pes : Pemphigus : Keratitis vasculosa — Malarial Keratitis : Keratitis Interstitialis : Syphilitica—Suppurativa — Ulcera- tiva—Purulenta discreta—Ulcus Corneae Serpens: Neuro- paralytic Keratitis : Kerato-malacia—Ulcers—Keratitis postica, Dendritica, or Arborescens—Mycotica, Interpalpebral De- generation—Sclerosis—Arcus senilis: Sequelae—Opacity: Fistula —Staphyloma, Cornea conica: Morbid Growths,.... 371-423 CHAPTER VI. THE SCLERA. Anatomy—Episcleritis—Scleritis—Sclero-keratitis—Staphyloma, . 424-429 CHAPTER VII. THE IRIS. Anatomy and Physiology — Mydriasis — Myosis — Hippus — Irido- donesis—Congenital Defects : Albinism—Irideremia—Coloboma Membrana pupillaris — Iritis: Serosa, Spongiosa, Plastica, Suppurativa—Complications : Symptoms—Sequelae—Causes- Prognosis— Treatment — Varieties: Syphilitic, Rheumatic, Gouty, Gonorrhceal—Tumors—Tubercles—Sarcoma—Cysts, . 430-453 X CONTENTS. CHAPTER VIII. OPERATIONS ON THE IRIS. PAGE Iridectomy—Iridotomy—Iridorhexis—Iridavulsion—Corelysis—Iri- dodesis, . ..........454-461 CHAPTER IX. THE CILIARY BODY. Anatomy—Ciliary Muscle —Cyclitis : Serous, Plastic, Purulent, Acute and Chronic : Traumatic—Hypotony—Ophthalmomala- cia: Morbid Growths,.........462-470 CHAPTER X. THE CRYSTALLINE LENS. Anatomy — Development — Images of Purkinje — Arcus senilis Lentis—Dislocation,..........471-477 CHAPTER XI. CATARACT. Pathology — Symptoms — Examination — Varieties — Diagnosis— Complications — Prognosis — Treatment—Soft Cataract—Dis- cission—Simple Linear Extraction—Extraction of Hard Cata- ract, with Iridectomy, without Iridectomy—Secondary Cata- ract—Glasses for Aphakia.........478-511 CHAPTER XII. THE VITREOUS BODY. Anatomy—Hyalitis—Persistent Hyaline Artery—Synchisis Scintil- lans—Muscae Volitantes — Cysticercus — Membranes—Hemor- rhage—Foreign Bodies,.........512-518 CHAPTER XIII. WOUNDS ASD INJURIES. Contusions and Blows—Wounds—Foreign Bodies—The Magnet— Burns,.............519-530 CHAPTER XIV. SYMPATHETIC OPHTHALMIA. Irritation—Inflammation—Causes—Stages—Prognosis—Symptoms —Neuro-retinitis—Mode of Transmission—Treatment— Iridec- tomy— Enucleation—Optico-ciliary Neurectomy—Exenteration —Risk of Enucleation,.........531-547 CHAPTER XV. GLAUCOMA. Degrees of Tension—Glaucoma Simplex—Symptoms—Development —Glaucoma Acutum—Subacutum—Chronicum—Hemorrhagi- eum — Secondarium — Buphthalmus — Diagnosis—Prognosis— CONTENTS. XI Etiology and Pathogenesis — Pathology—Treatment—Iridec- tomy — Sclerotomy — Posterior Sclerotomy—Malignant Glau- coma—Cystoid Cicatrix—Rationale of Iridectomy—Results, . 548-572 CHAPTER XVI. THE CHOROIDEA. Anatomy—Albinism—Coloboma—Choroiditis—Pathology—Colloid Degeneration—Symptoms and Subdivisions—Metamorphopsia —Megalopsia—Micropsia—Treatment—Choroiditis Metastatica —Panophthalmitis Suppurativa—Laceration of the Choroid— Hemorrhage—Detachment—Tubercles—Tumors—Ossification, 573-593 CHAPTER XVII. THE RETINA. Minute Anatomy—Opaque Nerve Fibres—Coloboma of the Macula —Hyperaemia—Pulsations of Arteries and Veins—Anaemia- Spasm of Arteries—Ischaemia—Embolism and Thrombosis— Hemorrhage—Retinitis Apoplectica—Miliary Aneurisms—Re- tinitis: various appearances—Etiology—Acute Traumatic Retin- itis—Retinitis Simplex—Albuminurica under various conditions — Pathology — Glycosurica — Leucocy thaemica — Syphilitica— Proliferans — Punctata Albescens—Pigment Degeneration— Neuro-retinitis pigmentosa—Detachment—Pathogenesis —Gli- oma—Pseudo-glioma,.........594-640 CHAPTER XVIII. THE OPTIC NERVE. Anatomy and Physiology of Optic Nerve, and of Brain connected with it—Coloboma of Sheath—Opaque Nerve Fibres^Con- nective Tissue on Disc—Hyperaemia—Anaemia—Hemorrhage— Papillitis—Neuro-retinitis—Neuritis Hemorrhagica—Peri-neu- ritis—Subjective Symptoms—Pathological Anatomy—Etiology — Pathogenesis — Prognosis— Treatment — Retrobulbar Neu- ritis: Chronic, Acute, Toxic, Alcoholic, Tobacco—Atrophy of Optic Nerve—Morbid Anatomy........641-693 CHAPTER XIX. AMBLYOPIA AND AMAUROSIS. Traumatic—Concussion of Spinal Cord—By Lightning, from Hem- orrhage—Toxic: by Quinine, by Salicylic Acid—Uraemic—Gly- cosuria by Pregnancy—Hysterical—Dyslexia, Paralexia, Alexia — Hemeralopia—Snow-blindness—Dental Amblyopia—Hyper- esthesia—Hemianopia: monocular, homonymous, binocular, nasal, bitemporal—Causes—Diagnosis—Amaurosis in Young Children — Fndiscovered Monocular Blindness — Simulated Blindness.............694-721 CHAPTER XX. THE ORBIT. Anatomy — Periostitis Orbitae— Cellulitis—Phlegmon—Inflamma- tion of Oculo-orbital Fascia—Thrombosis of Veins and of Cav- Xll CONTENTS. ernous Sinus—Tumors—Tumors of Optic Nerve—Extenteratio Orbitae—Pulsating Exophthalmus—Enophthalmus Traumaticus —Empyema of Frontal Sinus—Hemorrhage into Orbit—Wounds and Injuries—Fractures—Wound of Optic Nerve — Foreign Bodies in Orbit—Exophthalmic Goitre,..... CHAPTER XXI. USE OF ARTIFICIAL EYES. Mules' Artificial Vitreous,.........768-770 CHAPTER XXII. STATISTICS OF EYE DISEASES. Relative Proportion of Eye Diseases—Cohn—Causes of Blindness, Magnus, etc.,...........771-776 PAGE 722-767 Bibliography, 777-780 LIST OF ILLUSTRATIONS. FIG- PAGE 1. Section of Eye, horizontal.............................Heitzmann. 3 2. Ciliary Region.........................................Heitzmann. 4 3. Section of Eye showing Uvea..................Merkel, G. and S. 5 4. Blood-vessels of Eye.......................................Leber. 7 5. Refraction by a spherical Surface................................. 11 6. Cardinal Points..........................................Landolt. 13 7. Angle Alpha, angle Gamma, etc..........................Landolt. 14 8. Reflex from Cornea and Lens..........................Hehnholtz. 16 9. Changes during Accommodation..........................Landolt, 17 10. Relative Accommodation..................................Loring. 19 11. Retina : Macula Lutea....................................Strieker. 20 12. Blind Spot.............................................Helmholtz. 21 13. Perimeter.........................................Priestley Smith. 25 14. Boundaries of Color Sense.......•........................Landolt. 27 15. Optogram on Retina........................................Ayers. 33 16. Oblique Illumination.......................................Noyes. 36 17. Ophthalmoscopy—direct Method..........................Noyes. 40 18. Ophthalmoscopy—indirect Method.........................Noyes. 41 19. Loring's Ophthalmoscope................................Loring. 42 20. Loring's Ophthalmoscope..................................Loring. 43 21. Noyes' Ophthalmoscope...................................Noyes. 45 22. Optic Disc Surface and Section...........................Landolt. 48 23. Blood-vessels of Retina.....................................Leber. 49 24. Varieties of spherical Lenses................................Ganot. 53 25. Cylindric Lenses............................................Noyes. 54 26. Nachet's Spectacle Frame..........................Tiemann & Co. 58 27. Emmetropia, Hypermetropia and Myopia............ ___Brown. 69 28. Course of parallel Rays in convex Lens.....................Ganot. 69 29. Parallax of Vessels in excavated Disc.............................. 75 30. Explanation of Shadow Test........,..................Nettleship. 77 31. Explanation of Shadow Test............... ...........Nettleship. 78 32. Scheiner's Test..........................................Follin. 82 33. Myopia with Crescent..................................Nettleship. 97 33a. Section of Myopic Eye.................................Nettleship. 97 34. Myopia with choroidal Lesions............................Jaeger. 98 35. Supratraction of Optic Fibres in Myopia...................Weiss. 98 36. Myopia, Choroidal Crescent................................Jaeger. 99 37. Myopia, circum-papillary Atrophy........................Jaeger. 100 38. Myopia, Lesion at Macula .................................Jaeger. 101 39, 40. Course of Rays through cylindric Lens...................Fick. 113 41, 42, 43, 44, 45. Varieties of Astigmatism.................Hartridge. 115 xiv LIST OF ILLUSTRATIONS. FIG. PAGE 46, 47. Tests for Astigmatism...................................Green. 119 48. Tests for Astigmatism......................................Green. 120 49. Ophthalmometer of Javal and Schiotz......................Noyes. 124 50, 51. Images seen by Ophthalmometer.......................Javal. 125 33. Disc of Placido..............................................Noyes. 126 53. Axes of ocular Muscles...................................Landolt. 133 54. Converging visual Lines.................................. Follin. 136 55. Diverging visual Lines....................................Follin. 137 56, 57, 58, 59. Images in muscular Paralysis..... ...........Zehender. 142 60, 61, 62, 63. Images in muscular Paralysis................Zehender. 143 64. Section of Skull in frontal Plane through Sphenoid........Henle. 145 65. Base of Brain, Pons and Medulla................................. 146 66. Optic Commissure and Tract.......... .........Merkel, G. and S. 147 07. Oblique view of sagittal Section of Mid-brain..............Henle. 148 68. Diagram—Lesion of Pons with alternating motor Paralysis.. Starr. 149 69. Diagram—Lesion of Pons with alternating Anaesthesia.... Starr. 149 70. Section of caudal Edge of anterior Corp. Quadrigem.. Obersteiner. 150 71. Sagittal Section of Medulla modified from Edinger................ 151 72. Diagram of Nuclei in Medulla...............................Knies. 152 73. Nuclei of third and fourth Nerves...........................Perlia. 153 74. Nuclei of third and fourth Nerves........................Edinger. 153 75. A. Section of Brain on median Plane........................Starr. 156 B. Localization Centres....................................Starr. 156 76. Horizontal Section of internal Capsule.................M. Foster. 157 77. Strabismus Forceps................................................ 189 78. Strabismus Hook.................................................. 189 79. Refraction by a Prism......................................Ganot. 198 80. Displacement of Object by Prism................................. 199 81. Adduction by Prisms.................,............................ 199 82. Abduction by Prisms.............................................. 200 83. Metric Angle.................................................Nagel. 203 84, 85. Prisms in Series for testing at a remote distance........Noyes. 211 86. Prism-Carrier for testing at the working distance..........Noyes. 213 87. Speculum, flat View.......................................Noyes. 238 88. Speculum, profile View............................... ......Noyes. 239 89. Tarsi Palpebrarum.....................................Schwalbe. 247 90. Exterior of Eye and Lids................................Schwalbe. 248 91. Section through Globe and Orbit.......................Schwalbe. 249 92. Section of upper Lid...................................Schwalbe. 251 93. Eye-lid Clamp Forceps...................................Noyes. 254 94. Operation for spasmodic Entropium........................Meyer. 264 95. Hotz's Operation for Entropium.............................Hotz. 266 96. Green's Operation for Entropium...........................Green. 266 97. Ectropium at inner Canthus...........................Galezowski. 269 98, 99, 100, 101. Operations for Ectropium............,.......Meyer. 270 102, 103. Blepharoplasty........................................Noyes. 274 104, 105, 106, 107. Blepharoplasty..............................Noyes! 275 108. Blepharoplasty..............................................Noyes. 276 109, 110, 111, 112. Blepharoplasty---..........................Noves. 277 113. Laceration of upper Lid....................... ..........Lawson 279 114. Wound of lower Lid, etc....................................Noyes. 279 115, 116. Operation for Ptosis................................Wecker 28(* LIST OF ILLUSTRATIONS. xv FIG- PAGE 117, 118. Symblepharon.........................................Meyer. 289 119. Abscess of lachrymal Sac...................................Noyes. 296 120. Empyema of frontal Sinus.................................Noyes. 297 121, 122. Lachrymal Knives........................................... 300 123, 124, 125, 120, 127. Lachrymal Probes............................... 300 128. Gouge for lachrymal Duct..................................Noyes. 303 129. Abscess of lachrymal Sac..................................Noyes. 305 130. Desmarres' Elevators.......... ................................... 324 131. Gonococci.................................................Michel. 326 132. Trachoma Follicles..........................................Fuchs. 345 133. Forceps for follicular Trachoma...........................Noyes. 349 134. Squeezing follicular Trachoma.............................Noyes. 349 135. Gibson's Forceps for everting Lids................................ 353 136. Pterygium......................................................... 369 137. Corneal Corpuscles___...................................Strieker. 373 138, 139. Keratitis Mycotica......................................Haab. 376 140. Ulcer of Cornea........................................Galezowski. 380 141. Herpes Corneae.............................................Haab. 384 142, 143. Teeth in hereditary Syphilis and from Mal-nutrition.. Noyes. 391 144. Keratitis with Hypopyum.............................Galezowski. 397 145. Keratitis Postica.....................................Galezowski. 408 146. Keratitis Dendritica (vel Arborescens)..............Hansen-Grut. 409 147. Tattooing Needle................................................ 413 148,149,150. Staphyloma Corneae................................... 415 151. Operation for Staphyloma Corneae..........................Noyes. 418 152. Epithelioma Corneae ......................................Noyes. 423 153, 154. Membrana Pupillaris perseverans............................. 439 155. Congestion in Iritis...................................__......... 441 150. Posterior Synechiae.....................................Sichel, Jr. 441 157, 158. Occlusion and Exclusion of Pupil...................Sichel, Jr. 444 159, 160, 161. Forceps, Tyrrell's Hook, and Lance Knives.............. 455 102. Matthieu's Iris Forceps............................................ 450 -03, 104. Iridectomy.............................................Meyer. 457 165, 166. Iridectomy...................... ......................Meyer. 458 167. Wecker's Forceps-scissors...............................Wecker. 459 168, 169, 170. Iritomy Knife-needles.................................... 400 171, 172. Ciliary Muscle in H. and M... .......................Iwanoff. 463 173,174. Plastic Cyclitis ..........................................Alt. 465 175,176. Irido-Cyclitis.............................................Alt. 465 177,178. Plastic Cyclitis..........................................Alt. 465 170, 180, 181. Results of Cyclitis ................................Noyes. 468 182. Eye of embryo Calf at third Month.......................Kolliker. 471 183. Images from Cornea and Lens........................Helmholtz. 472 184. Dislocation of Lens...................................... Lawson. 474 185. Zonular (laminated) Cataract...............................Meyer. 483 186, 187, 188. Congenital Cataract...............................Wilde. 484 189, 190. Congenital Cataract ...................................Wilde. 484 191. Anterior Polar Cataract....................................Wilde. 484 192. Discission of Cataract.....................................Meyer. 490 193. Linear Extraction of Cataract upward.....................Wolfe. 492 194. Linear Extraction of Cataract outward.....................Meyer. 493 395. Section of Cornea in various Methods of Cataract Extraction..... Sichel, Jr. 496 XVI LIST OF ILLUSTRATIONS. FIG. PAGE 196. Graefe's linear Extraction—making the Section.............Noyes. 497 197. Graefe's linear Extraction—making the Section ...........Meyer. 498 198. Wire Retractor for upper Lid..............................Noyes. 499 199. Cataract Knife.................................................... 504 200, 201. Cystitome and Spatula : Fixation Bident.................. 504 202. Secondary Cataract...................................Galezowski. 508 203, 204, 205. Knife, Needles, and Hook for membranous Cataract..... 509 206. Persistent hyaloid Artery...................................Little. 513 207. Connective Tissue in Vitreous..............................Jaeger. 514 208, 209. Irido-dialysis : Rupture of Sclera...................Lawson. 519 210. Wound of Cornea, Eyelid and Cheek......................Noyes. 522 211. Appliance for oblique Illumination.........................Noyes. 523 212. Iridectomy after sympathetic Ophthalmia ...............Lawson. 539 213. Myopia and Glaucoma ....................................Jaeger. 549 214, 215. Excavation of optic Nerve : Glaucoma................Jaeger. 550 216. Sclerotomy—downward or bilateral.......................Lawson. 565 217. Colloid Deposits in Choroid................................Mtiller. 575 218. Patch of Choroiditis.......................................Michel. 576 219. Exudative Choroiditis ; peripheral.....................Jaeger, j 220, 221, 222, 223, 224. Atrophic Choroiditis.................Jaeger, f Plate 225. Choroiditis atrophica in Myopia............................Jaeger. 582 226. Diagram of minute Structure of Retina..................Strieker. 595 227. Minute Anatomy of Retina......................Perrin et Poncet. 596 228. Embolism of Arteria Centralis Retinae............. .....Magnus. 602 229. Dilated Choroidal Capillaries....................Perrin et Poncet. 605 230. Section of Retina in Morbus Brightii.......................Weeks. 617 231. Retinis albuminuria......................................Weeks. 618 232. Section of Iris in Albuminuric Retinitis....................Weeks. 619 233. Choroidal Lesion in Albuminuric Retinitis.......Perrin et Poncet. 619 234. Retinitis Pigmentosa......................................Meyer. 628 235. Optic Commissure and Tract....................Merkel, G. and S. 641 236. Medulla Oblongata and Pons.............................Edinger. 642 237. Diagram of Optic Tractus Fibres, etc....................Edinger. 643 238. Scheme of Cerebral visual Apparatus................Obersteiner. 646 239. Sections of Occipital Lobe, to show visual centre........Henschen 648 240. Schweigger's Perimeter................................Schweigger. 653 241. Transverse Section of Skull.................................Henle. 654 242, 243. Cerebral Convolutions................................Gowers. 655 244. Localization Areas on Brain Surface........................Starr. 656 245. Functional Centres of Brain Surface.......................Berger. 656 246. Connective Tissue on Optic Disc........................Massillon. 659 247. Hemorrhage within Optic Nerve Sheath.........Priestley-Smith. 661 - 248. Papillitis—Section of Globe............................. Allbutt. 663 249. Distention of Optic Sheath in Neuritis .. Pagenstecher and Genth. 667 250. Optic Neuritis—Microscopic Section---Pagenstecher and Genth. 668 251. Optic Neuritis—Longitudinal Section---Edmunds and Lawford. 669 252. Optic Neuritis—Cross Section...........Edmunds and Lawford. 670 253. Optic Neuritis—Cross Section.............................Uhthoff 685 254. Optic Neuritis—Cross Section.............................Uhthoff 685 255. Atrophy of Optic Nerve....................................Jaeger. 690 256. Section of Optic Nerve, Normal..................Perrin et Poncet 691 257. Section of Optic Nerve, Atrophic................Perrin et Poncet 691 LIST OF ILLUSTRATIONS. xvii FIG. PAGE 258. Diagram to illustrate left Hemianopia.....................Seguin. 715 259. Angioma of Orbit and neighboring Skin......................Bull. 739 260. Plastic Operation for Occlusion of Orbit....................Noyes. 742 261. Empyema of Frontal Sinus................................Noyes. 749 262. Diagram of origin of Ocular Muscles at Orbital Apex......Merkel. 755 263. Section of Muscles at Apex of Orbit.......................Merkel. 755 264. Section of Skull through Optic Canals.......Berger and Tyrman. 758 265. Patient with Foreign Body (Breech-pin) in Orbit, etc......Noyes. 762 266. The above-mentioned Foreign Body (natural size)..........Noyes. 763 267. Skull prepared to show the Position of the Breech-pin in the Orbit and Cranial Cavity—the Separated frontal Bone Exhibits the Place of Trephining for Cerebral Abscess................Noyes. 763 268. Exophthalmic Goitre.....................................Noyes. 764 269. Artificial Eyes ..................................................... 769 t DISEASES OF THE EYE. PART FIRST. CHAPTER I. GENERAL ANATOMY OF THE GLOBE. The eyeball is a spheroid, rotating in the orbit, upon a cushion of fat and fibrous tissue, and protected by the eyelids. The fibrous membrane on which it rests, called oculo-orbital fascia or capsule of Tenon, is shaped into a cup and moistened by serum: and in front it is lubricated by secretion from its covering membrane, the conjunctiva, and from the lachrj'mal glands. It consists externally of the cornea and sclerotica or sclera. A line perpendicular to the centre of the cornea is its antero-posterior diameter or axis; and intersecting this at the centre of rotation we have the vertical and the transverse axes. A plane through both vertical and antero- posterior diameters will touch the surface on its vertical meridian. A similar plane, passing through the transverse and antero-pos- terior axes, will form at the surface the horizontal meridian. The plane passing transversely through the vertical meridian forms the equator, and the extremities of the antero-posterior axis are the poles of the eye. All planes going through the geometrical centre form principal meridians or great circles. Planes vertical to the axis but not passing through this centre form lesser circles. or those of latitude. At birth the normal length is 17.5 mm. and the full size is not reached until after puberty. The following table of measurements is 1 2 DISEASES OF THE EYE. mm. compiled from various authors, viz., Jaeger, Merkel, Reuss, etc.; chiefly from Merkel. Antero-posterior diameter externally, Transverse, " Vertical, Sclera, thickness behind, Cornea, thickness at apex, " " " margin, . " radius of front surface, . " diameter of its base (Jaeger, 12 mm.) " height of apex above base, Pupil, average diameter, Lens, thickness (axis) in repose1 (Reuss), " equatorial diameter, " radius of anterior surface (Reuss), " " " posterior " (Reuss, 8.2 mm.) Aubert, 6. Distance from outer surface of cornea to lens (Horstmann), 3. (Apparent distance .5 mm. less.) Depth of anterior chamber, . Vitreous axis,..... Retina, thickness at optic disc, " " at fovea centralis, " diameter of fovea centralis, Optic disc, diameter, Distance from centre of optic disc to centre of fovea, Internal axis of eyeball from apex of cornea to surface of fovea (Becker),........23.8" 24.3 23.6 23.4 1. .9 1.1 7.7 11.6 2.6 4. 3.8 7 to 10.3 10.6 2.6 15.1 .4 .1 .4 1.4 4.0 .2 to Absolute accuracy in all these details is not attainable; even the length of the axis measured to the fovea centralis is not settled, because it is not absolutely uniform among normal eyes. For further details see Nagel2 and Becker.3 Going from before backward we find the following parts, viz.: the cornea; the space called aqueous chamber filled by aqueous humor, and which contains also the iris; it divides the aqueous chamber into the anterior and posterior chambers, and is itself perforated by an opening, the pupil; the crystalline lens, inclosed in a capsule which by certain fibres is attached at its edge to the tips of the ciliary processes; behind the lens the corpus vitreum or vitreous humor; in contact with the vitreous is the retina,* into which passes the optic nerve * 1 "Untersuchungen fiber die optische Constanten Ametropischer Augen " Graefe's Archiv, xxiii., 4, p. 183. 2 G. u. S. " Handbuch," Bd. ii., pp. 280 to 290*. 3 Ibid., Bd. v., pp. 432 to 442. GENERAL ANATOMY OF THE GLOBE. 3 external to the retina is the choroid, which, at a place near the corneal edge, takes the name of ciliary body, and is raised into folds called ciliary processes, and is also continuous with the iris ; outside of the choroid and in front, joined to the cornea, is the sclera, which behind is continuous with the sheath of the optic nerve. The optic nerve passes through the sclera and choroid and joins the retina. Figure 1 illustrates and describes the facts mentioned. For practical purposes it is important to understand correctly the relations of the parts composing the anterior half of the eye. The subjoined diagram, Fig. 2, presents them, in most respects, satisfactorily. The edge or limbus corneal is a ring-shaped space about 1 to 2 mm. in breadth whose borders are often very ill defined; the epi- thelium hero increases in thickness and merges into the conjunctiva. A practical point to be noted is that the limit of the transparent 4 DISEASES OF THE EYE. cornea lies in front of the place from which the iris springs; hence, the anterior chamber can be punctured through the sclera. A clear perception of this fact is indispensable in operating at this region. The existence of that congeries of vessels called the canal of Schlemm or the circular venous sinus, is also to be noted. It has important relations to the physiology of the anterior chamber. It is the outlet by which the aqueous humor finds its way into the circulation, and is supposed by Schwalbe to have in its wall minute clefts for this purpose; but this is disputed by Leber. At the angle are to be found delicate fibres passing from the cornea across to the iris. They are insignificant Fig. 2. in man, and are called the pectiniform ligament. In lower animals, viz.: in the ox and in swine, etc., they are more de- veloped, and constitute the canal of Fontana.' Upon theories of intraocular pressure, the parts now alluded to have important significance. The aqueous humor is derived from the vessels of the iris and ciliary processes. The posterior chamber is entirely shut off from the anterior chamber by contact of the iris with the lens and even when the pupil is well dilated the contact continues ' The anterior chamber appears to have much less than its real denth which is from 2.6 mm. to 3.5 mm., for the same reason that a brook is likely to deceive us as to the depth of water. Refraction brings the ins nearer than it really is, and likewise betrays us into wadin-deet er than we thought to go. In each case we may have cause for vegZ GENERAL ANATOMY OF THE GLOBE. 5 The sphincter of the iris makes the pupillary part of the membrane thicker than the rest of it. Another point to be observed is that the ciliary processes do not touch the rim of the crystalline. There is always a separation between them. The zonula of Zinn, or sus- pensory ligament of the lens, comes from the posterior surface of the ciliary processes, and is attached to the lens-capsule (see Fig. 1.) It splits into fine fibres, of which more go to the anterior surface of the lens than to the posterior. Passing to the deep part of the eye, we have the retina, begin- ning at the optic nerve and lining the concavity of the globe to the posterior edge of the ciliary body. Because this edge is irregular it is called the ora serrata. The retina is transparent and near the optic nerve is thicker than at any other part. At a point 4 mm. from the centre of the nerve, on its temporal side, and about 1 mm. below it, is a depression called the fovea centralis. Around it the retina has a faint yellowish or tawny color over an ill-defined elliptical space, and this region is called the macula lutea, or yel- low spot. Its greatest diameter, which is horizontal, is about 0.8 mm. The thickness of the retina near the nerve is 0.3 mm. The fovea centralis is 0.2 mm. in diameter. Outside of the retina is the choroid, which is perforated by the optic nerve, and consists chiefly of blood-vessels and pigment and connective tissue. The pigment is of a dark brown color, and varies in amount in different persons. We find a layer of hex- agonal epithelium, filled with pig- ment-granules and each contain- ing a nucleus; this was formerly assigned to the choroid, but is now regarded as the most exte- rior layer of the retina. In the choroidal stroma are irregular cells with stellate processes and nuclei filled with pigment-gran- ules. There is also free pigment scattered among the vessels. The choroidal vessels will be mentioned hereafter. At the point where the retina terminates, or no longer possesses nerve-elements, we have the beginning of that part of the choroid called the ciliary body (Fig. 3). It is divided into the pars non plicata behind, and the pars plicata in front. The plicae or folds are some seventy in number, and of unequal length. They consist of a congeries of vessels, which in front lift themselves up into projecting masses, and are called the ciliary processes. The great abundance and Fig. 3.—Cc, Cilliary process; Vv, venae vorticosse. 6 DISEASES OF THE EYE. plexiform arrangement of blood-vessels in the choroid and ciliary processes is necessary to secrete the pigment and to furnish nutri- tive material for the vitreous body and lens, which have no blood- vessels. Outside of the ciliary body, inserted between it and the sclera, is a mass of muscular fibres, known as the ciliary muscle (see Fig. 2). Its most exterior fibres run in the meridians of the eye; those which lie next, run in oblique directions whichjslant more and more as we go deeper, until we come to the innermost set, which take a circular direction. The whole mass, in meridional section, has a tri- angular form, whose apex and point of attachment is near the canal of Schlemm. For reference to the variations in its form and size, see chapter on refraction. The place of attachment is called by Gerlach the ligamentum annulare. The anatomy of this region of the eye was long misun- derstood, and there is likely to be confusion from the variety of terms which have been employed at different periods. The inser- tion of the ciliary muscle is upon the choroid, and its effect is to relax the fibres which pass from the tips of the ciliary processes to the margin of the lens, and which fibres are known as the zonula of Zinn, or suspensory ligament of the lens. This name is also ex- tended to a transparent membrane which lies between the ciliary body and the vitreous. The purpose and effect of the ciliary muscle is to permit the crystalline lens to become more convex. The space between the ciliary processes and the margin of the lens has im- portance in reference to the escape of fluid from the vitreous to the canal of Schlemm and the exterior circulation of the eye. The iris has pigment, blood-vessels, epithelium, and also muscular fibres which regulate the size of the pupil ; iris, ciliary body, and choroid, are together known as the uvea. We have next to speak of the vessels of the eye, and for much of our knowledge of the details of their arrangement we are in- debted to Leber, whose diagram is introduced below (Fig. 4). There are four systems of vessels, which may be distinguished from each other: 1st, the arteria centralis retinae, which enters the eye through the optic nerve, is destined exclusively for the retina and optic nerve, and forms few anastomoses with other vessels, and those chiefly at the edge of the optic disc (rami com- municantes). At the choroidal opening through which the nerve passes to reach the retina is found the only communication between the retina and choroid, and the optic nerve, and it is known as the circle of Holler. There is also communication between the sheath of the nerve near the sclera and the above-mentioned vessels. The retinal system is remarkably isolated, and bv Cohn is classed as "a terminal system;" 2d,the posterior, or short ciliary arteries GENERAL ANATOMY OF THE GLOBE. 7 which perforate the posterior part of the sclera and supply the choroid, and, with the long ciliary arteries, are the chief source of the elaborate vascular system of the choroid, of the ciliary body, and of the iris; 3d, the anterior ciliary arteries derived from vessels which come from the recti muscles and perforate the sclera about four to six millimetres behind the cornea. They are visible to the naked eye, more or less conspicuously, and supply the ciliary body, the iris, and the anterior part of the sclera, and furnish the plasma Fig. 4. which nourishes the cornea. These vessels join with the branches of the posterior ciliary arteries, and at the border of the cornea send off loops, which constitute the peculiar vascularity of this re- gion. Moreover they here anastomose with, 4th, the vessels which have come from the ocular conjunctiva. It thus happens that for a zone about the cornea there is a system of vessels which have communication with the face and with the deep and the superficial tissues of the eye. The vessels proper to the conjunctiva are of 8 DISEASES OF THE EYE. darker hue than those more deep, and they can be moved about as the membrane is slipped over the sclera by traction of the lids. This statement of the anatomy of the vessels shows how untrust- worthy is any attempt to make a diagnosis of the locality of an inflammatory process by fixing attention chiefly on the kind of hyperaemia. The vascular phenomena are important as auxiliary evidence, but do not take the first rank in deciding a diagnosis. The non-vascular structures of the globe form so much of its bulk, that some statements respecting their nutrition and the lymph circulation will be proper; Schoeler1 and Knies2 have elaborately studied these questions. The fluid to supply the aqueous, to nourish the lens and to nour- ish the anterior part of the vitreous, comes from the ciliary processes and posterior surface of the iris (at Schoeler's "secretory angle"), while the deep part of the vitreous may have nourishment from the choroid through the retina. The current for the lens goes through the canal of Petit and does not seem to come from the vitreous (on this point Knies and Schoeler are at variance). The cornea may be nourished from the aqueous as well as from its adjacent vessels at the limbus. It, like the sclera, has no true lymphatic vessels, but numerous channels in its substance, through which fluid passes. It admits fluid both from in front and from behind, but the epithelium and endothelium greatly hinder the transit of fluid, as is proven when these layers are removed either mechanically or by ulceration. From the corneal substance the fluid passes into the veins, and also into the canal of Schlemm; and the intraocular lymph current is largely from behind forward to this point; while from the vitreous it also goes out along the perivascular lymph spaces of the venae vorticosa. Here it comes into the supra-choroidea and besides entering the general circulation it also makes its way into the inter-vaginal lymph space of the optic sheath. Stilling states that fluid passes from the deep part of the vitre- ous through the optic nerve along the space outside the effete hya- loid artery (Canal of Cloquet). The degree of fulness of the globe, or what is called intraocular tension, has important physiological and pathological bearings. Much study has been given to it. To a remarkable degree the in- traocular circulation is independent of the systemic vessels because shut within a special cavity, yet a slight relationship exists (Schul- ten3). The tone of its vessels and consequently the tension of the globe, are largely controlled by the nerves. For example, stimula- tion of the sympathetic in the neck contracts the ocular blood- 1 Jahresbericht, Berlin, 1882, pp. 52 to 92. 2 Archives of Ophth. and Otol., vol. vii., p. 347. B Graefe's Archiv, Bd. xxix., Abth. Ill, p. 1. GENERAL ANATOMY OF THE GLOBE. 9 vessels, and the effect may be sufficient to cause dilatation of the pupil. Both arteries and veins become smaller and the intraocular tension falls. The same result ensues from irritation of the spinal cord above the third or fourth vertebrae, but not below this point. Irritation of sensitive nerves, as when creosote is applied to the cornea, causes contraction of the pupil and increase of tension. A similar increase occurs after irritation of the sciatic nerve. If, on the other hand, the contractility of the vessels is destroyed, they passively dilate and tension rises. Prolonged pressure on the globe will have this result, as Donders observed, and if this be done by injecting fluid into the globe and subsequently allowing the pressure to fall, it does not return to the normal because the ves- sels have been paralyzed and remain dilated. Schoeler says that cutting the sympathetic increases the secretion of aqueous humor and diminishes its excretion. He also says that the fifth nerve con- tains fibres which influence secretion within the eye, and can in- crease, hasten, and modify it more when it is cut within the cranium, than after division of the sympathetic. He also asserts that he found these fibres to lie on the medial fourth of the width of the nerve; he cut the nerve three-quarters across behind the ganglion of Gasser, and because the innermost fourth remained, no changes occurred in the secretions of the eye. When these last fibres were cut the changes took place. Paracentesis of the anterior chamber is followed by paresis and enlargement of the vessels, and the aqueous humor becomes fibrin- ous. This proceeding, therefore, has ultimate effects which may be directly contrary to what is desired; and a similar remark applies to strong pressure by a bandage. In experimental research tubes called manometers are inserted into the eye, and the ordinary intraocular pressure is equal to twenty-five millimetres of mercury. CHAPTER II. GENERAL PHYSIOLOGY OF THE EYE. Refraction. Like the photographer's camera, the eye consists of an arrange- ment of lenses to throw a luminous picture upon a sensitive surface. The former we ha ve in the cornea with the aqueous humor, in the crystalline lens and the vitreous. The cornea and the lens are the essential refractive or dioptric apparatus. The sensitive or per- cipient structure is the retina. The properties of a lens are determined by (1) the transparency and homogeneity of its structure, (2) by its refractive power or index, (3) by its form; and (4) its effect is varied according to its distance from the surface on which the picture is formed. Absolute transparency is never met with in nature, and both the cornea and lens become visible by the light which cannot pass through but is reflected from their substance. Neither are these structures perfectly homogeneous and especially is this true of the lens. Refractive power or index signifies the ratio by which light falling on a medium, is diverted from its previous course through air—and it is assumed that the direction is not perpendicular, and that the surface of the medium is plane, and not curved. If air be called 1, the refractive index of the cornea is the same as of water, viz., 1,336, while the index of the crystalline is 1,437. All lenses have curved surfaces, and the form of the cornea and lens have been carefully studied. See table below. The greater the number of surfaces in a refractive system, the more complex the problem. As light goes from one medium to another of different refractive index it is deviated, and every surface must be taken into account. Moreover, the separation of the surfaces from each other has its influence. The first deviation is at the exterior of the cornea, and no other takes place until we reach the surface of the lens:—because we may neglect the thickness of the cornea, and the aqueous humor GENERAL PHYSIOLOGY OF THE EYE. 11 has no effect because its index is the same as that of the cor- nea. At the posterior surface of the lens another refraction occurs, making three in all. The following diagram represents the conditions in a simple optical sj^stem. Let a b represent a spherical surface separating a less refract- ing medium from one of higher refracting power. Let n be the centre of the curve, and draw O A through the centre and normal to the curve at p; the line O A becomes the axis of the surface and rays passing through this line are not deviated. All rays im- pinging perpendicularly upon a b, like m d and m' e, will also suffer no deviation but go to n. The point n is therefore called the nodal point. All other rays in passing through a b will undergo refrac- tion. If the medium on the side O be of lower index than the medium on the side A, rays going in the direction from O to A will be refracted toward the axis. Rays which are parallel to O A like m r' p[ X ^^^/" 4 Fig. 5. c d will be refracted to a point lying upon the axis, say at F2, and this point is called the posterior or second principal focus. If rays pass from the side A to the side 0, and are parallel to the axis, they will be refracted toward the axis, and will meet upon it at a point F', which is called the anterior or first principal focus. F1 is nearer a b than F2. The point P, where the optic axis cuts the sur- face, is called the principal point. The anterior principal focus F1, the posterior principal focus F2, the principal point P, and the nodal point n, are called the cardinal points of a refractive system. Let us apply these principles to the human eye. The simplest optical instrument is an eye from which the lens has been removed. We are then presented with only one refractive sur- face, and have to take account of its index and its curve. Rays from c O 12 DISEASES OF THE EYE. a luminous point farther than twenty feet or five metres from the eye may be considered to be parallel, because the degree of divergence possible with the average diameter of the pupil may be discarded. Parallel rays will be refracted by the cornea so as to unite at a focus 33.8 mm. behind it, if they fall upon its convex surface. If, however, parallel rays are supposed to pass in the opposite direction and fall upon the concave surface, they will unite at a point or focus 26 mm. in front of it. The first is called the posterior principal focus, the second is called the anterior principal focus of the cornea The difference between these figures is exactly the length of the radius of curve of the cornea, viz., 7.8 mm. In the crystalline surrounded by air, we have a bi-convex lens whose index is 1.437, and whose front surface is curved on a radius of about 10 mm. and the back surface on a radius of 6 mm. The principal focus is at about 50 mm., and this is the same both for the anterior and posterior principal foci, neglecting the thick- ness of the lens. Both for the cornea and for the crystalline sepa- rately, it is easy to determine by simple construction or by simple formulae the place and size of the image when the distance and size of the object is known. The curves are assumed to be spherical and the angles so small that they may be measured by the arc as well as by the sine without appreciable error. The optical centre for the cornea is the centre of curve, and this may be called its nodal point. The optical centre for the crystalline, if both its sur- faces had the same curve, would be midway between the extremities of its two radii, that is at its centre, but with unequal radii it is a little nearer the side having the shorter radius. If now we combine the cornea and crystalline at the distance at which they are normally separated, we have an optical problem much more difficult when we attempt to fix the place and size of the image. Gauss furnished its solution in a general way and ab- stractly, while Listing made special application of the theory to the eye. He also simplified the calculations, and made them ap- plicable to what he called the reduced eye, in which a single refrac- tive surface of a particular curve is substituted for the actual con- struction. For an explanation of the cardinal points of a compound optical system, reference must be made to other works, especially Landolt," The Refraction and Accommodation of the Eye/' trans- lated by Culver, Edinburgh, 1886. We shall only enumerate them as consisting of three pairs, viz., the anterior and posterior princi- pal foci, the anterior and posterior principal points, and the anterior and posterior nodal points. The first two are widely separated the one being in front of the cornea and the other at the fovea cen- tralis retina ; the second pair are close together and situated be- tween the cornea and lens ; the third pair are also close together and lie just behind the lens. The nodal points are usually spoken GENERAL PHYSIOLOGY OF THE EYE. 13 of as a single point, the posterior one being chosen. It is the opti- cal centre where rays cross, and its position determines the size of retinal images and the refractive quality of the eye. The subjoined diagram from Landolt indicates the position of all these points upon a schematic eye three times magnified. The measurements are thus tabulated: Fig. 6. Distance from the apex of the cornea A of the an- terior or first principal focus ', anterior focus ; " posterior focus; H' H", principal points ; K' K", nodal points; JV/, centre of motion; C, centre of cornea; BB, base of cornea; EL, major axis of the corneal ellip- soid; F, fovea centralis; O. point of fixation; K' O, line of vision; M O, line of fixation; O X E, angle alpha; O M A, angle gamma. 1 Archives of Ophthalmology (Knapp), vol. xii., p. l 1883 GENERAL PHYSIOLOGY OF THE EYE. 15 ual line. Where this intersects at X the axis of the cornea, is found the angle alpha which represents the displacement of the cornea from the visual line. Usually this is outward and then is called plus; sometimes it is inward and is then called minus, or it may not exist. In extreme cases it amounts to 12° on the horizon- tal plane, usually not more than 5°, and it may also deviate slightly in a vertical sense. In the crystalline we meet with another special feature, that its density and refractive index increase from the surface to the cen- tre. By its arrangement in layers its refractive power is increased. Neither is the lens alike in all its sectors, and for this reason the image of a luminous point like a star, is never a mathematical point, but has irregular radiations, and to each individual the stars have dissimilar radiations. Such are some of the irregularities of the optical structure of the eye. It becomes the equivalent of a lens whose focal length is 15.5 mm. or -| of an inch. This is most simply expressed by the diagrammatic eye of Donders in which the cornea has a radius of 5 mm.; the optic axis is 20 mm.; the nodal point is 5 mm. from the cornea and 15 mm. from the retina; while the anterior principal focus is 15 mm. in front of the cornea. By this model it is easy to reckon the size of images on the retina, and the results are approximately true. It is only necessary to divide the distance of the object in millimetres by 15 to show how much smaller is the retinal image than the object.1 A rod one metre in height placed at 15 metres distance (15,000 mm.) gives a retinal image 1,000 times smaller than itself and therefore 1 mm. in size. An object 10 mm. high at 300 mm., about 12 inches from the eye, gives an image one twentieth of its size, viz., | mm. In the example last cited we have introduced another element in the problem of refraction; we have brought the object near the eye. When this is done, the image no longer falls at the same dis- tance from the cornea, but retires to a point farther behind, in ac- cordance with the law of conjugate foci or reciprocal relation between object and image in all lenses. The nearer the object the more divergent become the rays, and the degree of divergence in- creases very rapidly as the object approaches, because measured by angular increase. The retina cannot retire and if no modification is made, either by increasing the convexity of the crystalline or by advancing its position farther from the retina, there can be no sharp and clear picture. Each luminous point of the object will not be represented by a point on the retina, but by a circle. The circles of dispersion often exhibit colors, chiefly blue and red, 1 See Donders1 "Accommodation and Refraction of the Eye," p. 178. 16 DISEASES OF THE EYE. by breaking the light into its component elements. To obviate this difficulty, the eye is provided with a means of adjustment or ac- commodation when objects are presented near it. Accommodation. If in a dark room a light be held in front of the eye, its image will be reflected from the surfaces of the cornea and of the crystal- line. That from the cornea though small is conspicuous, those from the lens are best seen with dilated pupil and when the light is held at one side. Purkinje called attention to them; Helmholtzutilized them to determine what happens when the eye adjusts itself to view a near object. He measured their size and the changes of ft ft a b c a b c a. eye in repose. b. eye during accommodation. Fig. 8. In A and B the light comes through square openings in a disc. a. Image from the cornea (erect). b. Image from the anterior surface of the lens. c. Image from the posterior surface of the lens (inverted). form and place which they undergo, by an instrument which he in- vented for this purpose—the ophthalmometer. We may sum up the changes in the eye during accommodation as follows: the pupil becomes smaller, the front of the lens becomes more convex, and, by advancing a little, carries with it the iris and reduces the distance between it and the cornea; the posterior sur- face of the lens becomes inappreciably more convex. The lens is thus increased in thickness and its equatorial diameter lessened. The ciliary processes swell. These changes of the ciliary processes have been proved by inspecting the eyes of albinoes, and eyes in which iridectomy has been performed (Coccius, Becker, Hiort). The active agent is the ciliary muscle, and the mode of its action is believed to be as follows: the muscle contracts, becomes thicker and presses the ciliary processes nearer the optic axis, and enlarges their volume. At the same time the fibres draw upon the zonula (suspensory ligament of the lens) and release the crystalline from the tension under which by its anatomical construction like h'ENERAL PHYSIOLOGY OF THE EYE. 17 bundle of watch springs, it is kept, and it, by its elasticity, increases its anterior convexity while its border grows more rounded. The distance between lens border and ciliary processes is not altered, neither does the lens increase in volume. The aqueous humor be- comes slightly displaced toward the periphery of the chamber, and the pupil diminishes. The actual increase of the axis of the lens, in accommodating from infinity to five inches, is 0.4 mm. The radius of the anterior surface of the lens is shortened from 10 mm. to 6 mm., the radius of the posterior surface from 6 mm. to 5-J mm. The lens increases from a central thickness of 3.6 mm. to 4 mm. (see Mauthner: " Vorlesungen," 1872, p. 20). The changes are shown in Fig. 9, copied from Landolt. The nerves which preside over the action of the ciliary muscle and the pupil are the ciliary, of which some come from the ciliary or lenticular ganglion, and. others from the large ciliary nerves. For further remarks see pupil, p. 432. What is the extent and course of the c accommodation ? We know that in early life the degree of accommodation is highest, and that it stead- ily diminishes. Donders, to whom we owe most of our knowledge on this subject, showed that if at ten years of age the nearest point of distinct vision is at 2.8 inches, at twent3T it has receded to 3.9 inches, at thirty to 5.7 inches, at fifty to 16 inches. At first thought, the diminution which occurs at the age of thirty does not seem important. We know that lenses are, in respect to their power, to each other inversely as their focal length. A lens of 4 inches focus is to one of 12 inches focus as i is to ^. The former is three times as strong as the latter, and the difference between them is \-^=\, that is, it equals a lens of 6 inches focus. Now, in comparing the accommodation at ten years of age with that pres- ent at thirty, we are to use the formula zj — &r = sj- In other words, by thirty years of age the eye has lost one-half its power of accommodation, at fifty years we have u - -5- = §t, which is a loss of almost TV its original accommodative power. The nearest point to which the eye can adjust itself is called the near-point of accommodation, denoted by the symbol P (punc- tumproximum). The farthest point of accommodation is denoted by the symbol R (punctual remotum), or far-point. The breadth or range' of accommodation is expressed by the formula, 7-^ and 18 DISEASES OF THE EYE. is equivalent to the difference in refractive power of lenses whose principal foci are P and R. The range of accommodation be- comes, therefore, a lens of definite focus, whose refractive power is expressed by f. Now, in normal eyes, up to about fifty-five years of age, R is at an infinite distance, and the refraction is denoted by l-i, that is, it equals the near-point. But, beyond this age, the far-point goes still farther away than infinity, an expression not absurd in mathematical language, and which means that the eye can now bring to a focus rays which are slightly convergent, and, as light from natural objects never travels in converging lines, a convex lens is needful to enable the eye perfectly to see distant ob- jects. The course of the accommodation is given in the subjoined table, constructed by Donders, and taken from Nagel (G. und S., Bd. VI., p. 46G), and is given both in metres and in English inches: Distance of Distance of Breadth of A. Age in Distance of P i;i Metres. Distance of R in Bletres. P in English Inches. R in English Inches. Years. Metres D. Inches. 10 0.071 oo 2.8 00 14 D 1: 2.8 15 0.083 oo 3.32 00 15. 1 2.3 20 0.100 00 4. oo 10. 1 4. 25 0 128 oo 5.1 00 8.5 1 5.1 30 0.143 oo 5.7 oo 7. 1 5.7 35 0.182 oo 7.2 oo 5.5 1 7.2 40 0.222 oo 8.88 00 4.5 1 8.8 45 0.286 oo 11.44 00 3.5 1 11.44 50 0.400 oo 16. 00 2.5 1 16. 55 0.666 —4. (H0.25) 26.64 —160. 1.75 1 41. 60 2. —2. (H0.5) 80. — 80. 1. 1 40. 65 —4. —1.33 (H 0.75) —160. — 57. 0.5 1 80. 70 —1. —0.8 (H 1.25) — 40. — 32. 0.25 1 160. 75 —0.571 —0.57 L (H 1.75) — 25. — 23. 0. 1 0. 80 —0.4 —0.4 (H 2.5) — 16. — 16. 0. 1 0. Another and familiar way of exhibiting the variations of accom- modation with age is by a diagram first employed by Donders and reduced to dioptries by Landolt. The above measurements relate to the accommodation of one eye by itself; they are not strictly true when both eyes, working simultaneously, are considered. The binocular accommodation is rather less than the monocular. In binocular sight the visual lines converge upon the object, and a suitable amount of A is exerted according to the distance of the object. There is, therefore a re- lation between convergence of visual lines and A. This relationship is of great importance in dealing with objects near the eye, and we speak of it as the relative accommodation. For a given angle of convergence it is possible for the eyes to put forth a greater and also a less degree of A than the distance of the object requires. We illustrate by a diagram, Fig. 9, in which, upon the line AB, the visual lines converge at a point O, which is at the same time the GENERAL PHYSIOLOGY OF THE EYE. 19 place for which the eyes are accommodated. While the visual lines remain at the same angle of inclination, it is possible to see O cor- rectly when it is viewed either through a convex glass, which will by so much diminish the effort of accommodation and place it vir- tually at A, or through a concave glass, which will compel greater effort of A, and make the object seem to be at C. If, with a person fifteen years old, O be taken at 12", then a convex glass about T1r can be used, which will carry the accommodation to 72 inches, while a concave glass, viz., about |, will be accepted, which will bring the Fig. 10. accommodation to 5.33" (Donders). The former, found by the con- vex glass, gives the negative side, and the latter, found by the con- cave glass, gives the positive side of the relative A. With parallel visual lines, concave glasses — TV can be overcome, which bring the object to 11 inches. But if convergence be at 4", concave glasses can no longer be used; only convex can be employed, and therefore the relative A is entirely negative. The practical result of these ■ investigations is that for a given amount of convergence there i must be a certain ratio of positive A to negative A, else the eyes ? soon grow weary. Graefe said that the positive side must be about 20 DISEASES OF THE EYE. equal to the negative, but age and the refractive quality of the eye make important differences. In later life when the accommodation has become much restricted, its reserve part very greatly diminishes and without any discomfort to the individual. While some reserve of relative A must remain experience shows that in this matter there is great diversity among individuals. Peculiarities of refraction and of muscular capacity have great influence. This subject will be again referred to when treating of muscular asthenopia. Functions of the Retina. The retina is made up of nerve-elements of peculiar structure, of the fibres coming to it from the optic nerve, of epithelium, and of con- nective tissue. The only elements we now need to consider are the bacilli or rods and cones. They are upon the outer surface of the retina, next the epithelium, and may be likened to the pile of velvet, because they stand per- pendicularly to its surface. At the fovea centralis they are most numerous and elongated, the cones alone existing here. The minute structure of the retina at the fovea centralis is shown in Fig. 11, which is taken from Schultze's schematic sec- tion, given in Strieker. The fibres of the optic nerve are the innermost of the nerve ele- ments ; thickest around the disc, at the fovea thej^ are thin- nest. They convey to the brain the impressions excited, and are themselves not capable of being stimulated by light. The blind spot (Mariotte) in each visual field is thus explained. If, with the right eye, one look at the cross in Fig. 12 (from Helmholtz) placed at about twelve inches distance, the circular white spot will correspond to the size of the vacancy in the field of most persons. The cross is above the level of the centre of the circle, because the fovea centralis is lower than the middle of the optic disc. Fig. 11. GENERAL PHYSIOLOGY OF THE EYE. 21 All parts of the retina up to the ora serrata are capable of per- ceiving light. The impressible surface is not quite a hemisphere, and if it stood out beyond the obstruction of the nose and the other surroundings of the eye, it would include within its scope a corre- sponding exterior hemisphere, or field of vision. The space which the eye at rest can cover in vision, varies according to the facial peculiarities of each person and the prominence of the eye from the orbit; we shall return to the subject of the visual field farther on. The middle of the retina is its most sensitive part, and when we give attention to an object, i.e., look at it, we turn the eye so that the object shall be imaged on the fovea centralis. We have already learned the size of the image for a given dis- tance of an object; we have now to inquire what is the smallest im- age which the retina is able to distinguish: in other words what is the normal acuity of vision? The problem must be taken on its Fig. 12. practical side, and it does not mean the perception of a point of light like a star. We have three properties in the retina, the form sense or acuity of vision, the color sense, and the light sense. Naturally the last is presupposed in both the others, yet sometimes it demands separate investigation. The determination of the form sense or acuity of vision has been studied by Helmholtz, Aubert and others as a problem of physiology. It is found that the smallest perceptible angle is one wThich forms an image covering two cones. For accurate vision the image must reach the outer extremity of the cones. The thickness of the retina at the fovea is .15 mm. The smallest visual angle for black lines on a white surface is taken by Aubert at 52". This corresponds to an image about .004 mm. long. Snellen, who first worked out the ques- tion of visual acuity in a practical way, has taken the angle of V (one minute) as the average degree of visual power. He has given the formula V = p to represent it. V stands for visus; d for the distance at which the object is placed, and D is the distance at which it ought to be seen and which is placed above the type. He has 22 DISEASES OF THE EYE. constructed test types with letters wiiose stroke shall at 6 metres subtend an angle of V, and the entire letter, supposed to be contained in a square, subtends an angle of 5'. The first editions of his test types were constructed upon the scale of Paris feet, the recent edi- tions are according to the metric scale, and for 20' we now take 6 metres. In the last editions the numbers formerly known as xx and xxx have been changed for smaller letters to correspond to the reduced distance, because 20 Paris feet = 6.5 metres. The separation between the letters has an important influence. In the English edition of Snellen, the interspaces are three fifths the height of the letters. White letters upon a black surface seem larger by irradiation. It appears that differences of illumination have less influence upon eyes with normal acuity than upon those with reduced acuity. An important consideration is the age of the subject. Cohn found the children in a village school among the mountains had, when tested by Snel- len's " hooks " (which are the characters to take the place of letters for those who do not know the alphabet) v = 2 in 47$ (114 eyes); v = 2 to \\ in 34$ (85 eyes); v = \\ to 1 in 15.5# (38 eyes); v = 1 in 2.8$ (7 eyes). Total of 244 eyes. In old age the opposite condition usually appears. Cohn, in 1874 (Nagel's Jahresbericht, Funfter Jahrgang, p. 210), examined 100 persons between 60 and 84 years, dwellers among the mountains. He found 88 eyes with v better than 1 and 34 eyes with v = 1. It is commonly said that v = \ is normal after 60. Among savages vision is always high. Occupation and mode of life also have an influence. Those who are occupied upon near objects and who do not live much in view of objects at a great distance usually have lower acuity. It would appear from Seggert's examinations that persons in health be- tween 20 and 25 years, who have v greater than 1, have as an average v=^^ (I.e., p. 98) and the visual angle is therefore 4' 14". This conclusion is after examination of 2,253 eyes. Another point to be mentioned is that binocular is better than monocular vision. Common experience testifies to this fact; while Seggert has shown that if one eye is inferior to the other, vision will in 85$ be equal to that of the better eye. Reference will be made to this hereafter, under the head of anisometropia. Snellen's types are the usually accepted standard, and they may be employed with the qualifications which have been set forth. Monoyer has given a table in which the series is made to progress- in tenths, from 1 to 0.1. This system is to be preferred over all others because of the regularity and smallness of the intervals between the sizes of types. (See p. 33.) Many other test types have been published; in some the visual angle is taken at 4'. In some the more difficult letters of Snellen are left out T) John Green, of St. Louis, has issued a table in which he adopts a plainer form of letter, Gothic rather than Egyptian, and he fills out gaps in the series of Snellen's types by making the series more correctly progressive in an arith- metical series. The spacing of his letters makes them more difficult to deci- pher than the English edition^ Snellen. For ignorant persons Snellen r -0" GENERAL PHYSIOLOGY OF THE EYE. 23 vided characters which the patient is to describe by telling which side of the figure is open and whither it points. Burchardt has a set of tests composed of dots arranged in groups, and of different sizes, and he takes the distance much greater than Snellen. His tests are for use in the military service and while he sets acuity higher than Snellen, it is not as easy to use his tests as Snellen's. Seggel, after careful comparison of the two on a large scale, gives Snellen's the preference (I.e., p. 84). Mauthner says that acuity which with Snellen may be 1, will with Burchardt be 1£. In testing a patient, he is placed at six metres from the card, or if this distance is not available, at the greatest distance possible. (Pfliiger has issued a set of letters which can be viewed by reflection in a mirror and so gain distance). The series extends from X to CC. If vision is better than 1 or | or H it will be perhaps ^ or 4- On the other hand it may be less than 1 and be ^k, jz or 4 (met- ric). If less than the last-mentioned amount, the card may be brought to the patient and the vision given accordingly, say 4 or if in feet ^-0 or less. The rule should always be observed to place the actual distance of the test types as the numerator of the frac- tion. When V is very low, say | (in feet) it is often impossible to decide between ^ and ^ and the same uncertainty may appear with V = £^. It is in this class of cases, that illumination has most influence. To this must be added the influence of the size of the pupil; because persons with low V, see with dispersion circles, and the smaller the pupil the smaller the circles of dispersion. It is surprising to note what sharpness of sight, or rather what "dis- cerning power," as Nagel calls it, will sometimes be found in persons who have slight opacities of the cornea, incipient cataract, astigma- tism, etc. Although the retinalimage is very badly outlined, they are able to draw inferences as to form and features which persons who rely chiefly on the accuracy of retinal images cannot in any degree compete with. Such persons show decidedly much better vision for near, than for distant objects. Hence, the little value which attaches to examinations by reading fine print. Power of accommodation, size of the pupil and skill in deciphering obscure characters, make such examinations untrustworthy as measures of visual acuity; although for the patients they have great practical importance and consolation. Certain letters are well known to be more easily recognized than others. Cattell experimented with a special apparatus on this matter. He viewed the letters for very brief periods of time in uniform light, and made 270 exposures of each letter. They were of the plainest form and the stroke of uni- form thickness. The order of legibility he found to be W Z M D HKNXAYOGLQISCTRPBVFTJJE. W was seen 241 times correctly; K N X A Y between 180 and 150 times; B V F U J about 100 times; E was recognized only 63 times out of the 24 DISEASES OF THE EYE. 270. In the small letters the order of legibility was d k m q h b pwuljtvzrofnaxyeigcs. He found that, to read a letter, light must act upon the retina from .001 to .0017 of a second, varying greatly in different individ- uals and in the same individual at different times. " The Inertia of the Eye and the Brain," Cattell, Brain, vol. 8, p. 294, 1885-86. It is understood that Snellen's types are to be viewed by good ordinary daylight. On cloudy days the visual power is naturally less. To avoid this inaccuracy, Dr. H. Derby proposed that the test should always be by artificial light. In all cases where the light is not normal, the observer, if his own vision be good, should com- pare the patient's vision with his own. That a much smaller visual angle is attained by some persons and that a very bright light, like direct sun, greatly increases acuity, is well understood. The value of illumination in affecting vision has been elaborately studied by Posch (Arch, of Oph. and Otol., v. III. and IV., p. 295, 1876), who form- ulates the law that under a given degree of illumination and with one which is 16 times greater, acuteness of vision increases in arithmetical progression, while illumination progresses geometrically; such a ratio of in- crease is observed, if the light be neither very feeble nor very intense. Seggel (Graefe's Archiv f. Ophth., Bd. XXX., II., 69, 1884, has given an analysis of his visual examinations in the German army, not employing pho- tometric methods like Posch, but noting the differences between bright and rainy days. His examinations were made in a barrack with windows to the north. He found that between bright sky and rainy weather, eyes which had v = —, or better, would show a difference represented by 6: 5. If, how- ever, in good light v = ^ the difference would be as 4: 3. For such as had v = |- the difference would be as 3: 2 (I.e., p. 87). Visual Field—Indirect Vision. Let us now study the functions of the eccentric parts of the retina. The first fact which wTe notice is, that outside of the fovea, acuity declines very rapidly. For instance, at 1° outside of it, acuity of vision is reduced to $; at 2° or 3° V = | (Konigshofer). If the fingers be spread widely, they can be counted at almost the outer limit of the field of vision. But, for the peripheral parts of the retina, we confine our examination to the recognition of form with- out attempting to ascertain discriminating power. This investiga- tion is called taking the field of vision. It is done for each eye alone the other being covered. To do this properly, an arc of a circle must be placed in front of the patient, which shall be not less than 90° nor more than 180° in extent. Its radius should be about 12 inches or 30 cm. The eye to be examined must be at the centre of the circle, and fixed steadfastly upon the point directly in front An object, the size of which will be chosen according to the accuracy GENERAL PHYSIOLOGY OF THE EYE. 25 demanded—generally a white object, 1 inch square, is suitable—will then be moved along the arc from its centre to its extremity, or bet- ter, vice versa. When the perception has been determined with the urc in one meridian, it must be turned to another, until the whole field has been explored. Beginning with the arc in the horizontal position, it will be carried around to the vertical position, and a de- termination made for each meridian at intervals of 15° or 30°. The examination is easily made by an instrument called a perimeter, in- vented by Aubert and put in practical form by Forster. Many others have been made, in some of which a true hemisphere is used (Schirk, Dyer), or a quadrant is employed. In some, a diagram of the field is automatically traced (Stevens, McHardy), while a simple form consisting of a quadrant, the invention of Priestley Smith (see Fig. 13), has a place in front of the ob- server for inserting a blank on which a diagram of the field can be quickly and easily pricked off. This instrument, which has been imitated by Meyrowitz, is the most convenient of all. In the absence of instru- ments, it is easy to take the field upon a flat surface for a distance 45° each way from the line of vision, because the tan- gent of 45° is equal to radius. If the eye be put at 15 inches from the wall, a circle on the wall with a radius of 15 inches gives 45°. If the space be divided into three equal zones, the first circle will be at 18° and the second at 33°. On such a surface, scotomata may be ascertained, but it is none the less important to investigate the peripheral parts of the field. The outlines of the visual field are far from symmetrical. Its greatest extent is on the temporal side. On the opposite side the limit is determined by the height of the nose, while above, the eye- brow, and below, the cheek, fix the extent of its boundaries. The position of the eye in the orbit, the configuration of the face, the size of the pupil, and the length of the optical axis, are factors which enter into the form of the field. Usually the extent on the temporal side is 90°; on the nasal side, 50°. Above it is 50°, and below it is 65°. These figures are liable to great variations in dif- ferent persons. To be sure that the full limit belonging to each 26 DISEASES OF THE EYE. case is secured, the observer may sight across the arc from extreme positions on the outer, inner, or upper sides, and note upon it the place across which he is able to catch a view of the patient's pupil. This marks the limit to which the field ought to extend, and should be noted on the chart as the boundary to which the field should correspond. The numbering of the meridians has not yet been uniformly agreed upon. By some, including Priestley Smith, the top of the vertical meridian is the starting point, and 180° are counted each way, the temporal side called plus and the nasal side minus. Others begin at the left (Forster) and go around 360°, 90° being at the top. The difference is not very important. We must always remember that the temporal sides of the fields correspond to the crossed fibres of the tractus optici, and the nasal sides to the uncrossed fibres. Moreover that the right halves of the respective fields belong to the left optic nerve and vice versa. At least three meridians should be taken in each quadrant. To get the field on the nasal side to its absolute limit, the eye may be turned to fix on a spot 30° to the temporal side. In glaucoma simplex this suggestion has value.. Sometimes the light must be greatly reduced to discover either limited defects within, or encroachments upon the periphery of the field. Another device sometimes helpful, is to make the patient face the window, and the glare of the light will sometimes bring out a limitation which would not occur in a normal eye. A perimeter is not needed to make out hemianopsia, such as happens from brain disease, and the same is often true of cases of detachment of the retina. The hand moved from point to point as the patient looks in the observer's face will discover the defect. A small and portable perimeter has lately been made by Schweigger which. is convenient for use at patients' homes. Measurement of the blind spot can be made by using a small bright test object with the perimeter. It is increased in some cases of myopia and of papillitis. It varies normally from 4° to 7° 30'. The measurement of the angle of converging strabismus can also be made with the perimeter by sighting across it to the eye which does not fix. The chief reason for the great reduction of visual acuity outside the fovea is the inferior sensibility of the retina. For objects very peripherically situated an additional reason would be anticipated in the distortion which images undergo when rays fall at very oblique angles. Fick, however has shown ("Handbuchder Physiologic" Hermann, p. 80), that the position of the crys talline and its laminated structure very largely antagonize this source of error, and that the eye is eminently periscopic. That there is not absolute accuracy may be seen in emmetropic eyes, which are always hypermetronic on very oblique axes. p GENERAL PHYSIOLOGY OF THE EYE. 27 Color Sense. Examinations of the color sense are called for in two classes of cases. First in those whose defect is caused by disease, and second in those in whom it is congenital. The two methods are unlike, and the conditions existent are also unlike. The pathologi- cal cases simply present modifications of the normal kind of percep- tion, and there maybe either a central region or a peripheral region deficient. The other class of cases, viz., those which are congenital, will be separately considered. The capacity for recognizing colors of every hue, pertains only to Fig. 14. the middle region of the retina. Much depends, however, on the purity and luminosity of the color as well as on the degree of light. Very large and luminous colored surfaces can be recognized at the extreme limits of the field, as for instance a red house in sunlight; but we are dealing with small objects. The colors employed are blue, yellow, red, and green, and we use bits of card of from 1 cm. to 4 cm. square for the field; while for central perception we reduce the size to 2 mm. square. There is a natural boundary of the area over which each color can be recognized, and this varies according to the color. Landolt has given the chart, Fig. 14, which maps the limits of the colors named. While within the :28 DISEASES OF THE EYE. boundaries of green, all other tints can be known, and for the red, also yellow and blue; and for the space within yellow, also the blue; outside of yellow,only blue can be seen (Fig. 13); and outside of blue, no color is recognizable. These color limits cannot be held to be uniform even among normal eyes, but they have value as a general statement. In making the test, a bit of card-board, 2 cm. square, of the proper tint, is put on the end of a rod and brought across the field, always beginning from the end of the perimetric arc. It is well to have different colors on its opposite sides, that, by turning the card around occasionally, we may guard against mistake or deception. One may have several rods, each having cards of differ- ent color, and thus be more sure of correct answers. It happens that patients may have a dimness of color-sense for a certain hue all over the field. This will be discovered by finding out that the fainter shades of a special color fail to be correctly noted. But it usually happens that more than one color is dimly discerned. It also happens that there may be a scotoma in the field of a particular color, as for example, red. For its detection a small card not more than two millimetres square is to be held at the centre of fixation, and a similar one a few degrees to one side •of it. The one at the middle ought to be equally brilliant with the other, while in the cases designated the eccentric card seems to have the brighter hue. The extent and boundary of the scotoma «an, by this means, be made out, provided the test be not continued for a period so protracted as to fatigue the color-sense. This ex- amination belongs to cases of tobacco or alcoholic amblyopia, etc. We find defective color sense in atrophy of the optic nerve, in chronic glaucoma, sometimes after apoplexy and injuries of the head, in amblyopia and amaurosis, and also in hysterical amblyopia. As a measure of direct color perception, Oliver1 states that at five metres one should recognize a red card of 3 mm. square, a green of 2 mm., yellow of 2.5 mm., and blue of 8 mm. Congenital defect of color sense, or Daltonism, has attracted great attention within eighteen years, and the literature of the sub- ject is copious. For proper understanding of signals on railways and ships, and in some other cases, defect in color perception produces liability to mistakes whose consequences may be suf- ficiently serious. That accidents have not occurred more fre- quently wlien color-blind persons have beeu responsible for the in- terpretation of signals, is due to their possessing in most instances very acute perception of shades and degrees of light. They are often unaware of their defect. The condition is frequently hered- itary. Horner gives a case of transmission from grandfather to 1 Archives -of 'Ophthalmology, vol. xi., p. 65, Am. Ed. GENERAL PHYSIOLOGY OF THE EYE. 29r grandson during eight generations. Both eyes are affected; yet six cases are on record where only one was concerned. The actual frequency of color blindness is on the average 5# among men and less than ty among women. The common error is inability to distinguish red from green, while other colors are appreciated. There are differences among these persons; some confound light red with dark green, and these are red blind, while others confound dark red with light green, and they are green blind. A much smaller class of persons have "blue-yellow" or violet blindness. Very searching and interesting studies have been made by Don- ders, Koenig,1 Hirschberg and others upon the vision of these per- sons with the solar spectrum. In place of red and green bands,, they see only yellow of varying intensity, and recognize very subtle shadings of light. With some, the spectrum is shortened at the red end, with others it is not. When candidates for employment in the service of a railway are to be tested, the method is by the worsteds of Holmgren, which are of all hues and tied in skeins. A mass of them, about 100, are thrown upon a white cloth and the person examined is asked to pick out tints which resemble the hue of certain standard test skeins. The first test is a skein of light green, the second test is a skein of light purple or rose, which is the complement of the green. A third test which is only confirmatory and suitable for persons whose de- fect is extreme, is a scarlet or brilliant red. The standard green is put into the person's hand, and with correct perceptions he has no difficulty in matching it with congruous colors. But if his color sense is defective, he will be guided not by the tint, but by the lumi- nosity of the shades. Blues and yellows he understands and avoids;. but among tints of a greenish hue he will take up grays, light browns, yellows, and skeins of tan and dove color, " confusion colors." He will hesitate over uncertain colors and when he has picked out all which he regards as similar to the green, this bunch will be put aside and he will proceed in the same way with the second test, the light purple or rose. In this hue red and blue are mixed, the red predominating. The first test shows that the color defect is of, the red-green variety; the second test will decide whether the defi- ciency is greater with red or with green. The red-blind individual chooses out the light reds and grays and greens, and avoids the dark. The green-blind selects the dark and avoids the light reds and violets. If with the second test only purple skeins are selected, the person is only partially color-blind for red and green. In case, besides purples, he picks out only blue and violet or one of themr he is completely red-blind. If with purple he selects only green and gray or one of them, he is completely green-blind. 1 Graefe's Archiv, xxx., 11, 154. 30 DISEASES OF THE EYE. The third test applies to those who are totally red-and-green blind and is confirmatory of the second. A method similar to the above has been devised by Dr. Wm. Thomson, of Philadelphia, in which the skeins are arranged upon a frame and numbered, and the results of the examination are re- - corded on charts. It enables the examination to be made with facil- ity by persons who have no expert knowledge, and the results can be sent to a central bureau.1 If the very rare case of violet or blue-yellow blindness should appear, purple, red and orange will be confused in the second test. Total color-blindness will be recognized by a confusion of all shades having the same intensity of light, and is also rare. Stilling has published isochromatic tables for detecting color- blindness. Colored letters made up of small blocks are printed on a ground of confusion color, and they consequently cannot be made out by the color blind. The edition of 1880 is the best. Donders used colored glass viewed by transmitted light. Woinow employed Maxwell's revolving discs; the method by colored shadows, and other methods have been used. Holmgren's worsteds are on the whole the most satisfactory. For elaborate details on this topic see Jeffries2 and Burnett.3 Very recently Prof. Langley (American Journal of Science, xxxvi., Nov., 1888) has published the results of experiments upon the perception of colors in normal eyes. He found among four persons, all of whom had supposably normal perceptions, extraordinary differences; two were myopic and their ability far exceeded the others. His general conclusion is that, apart from individual peculiarities, the time required for the distinct perception of a very faint light is about one-half second. The visual effect produced by any given -amount of (luminous) energy varies enormously according to the color of the light in question. For details see his paper and see also the article by Cat- tell in Brain, vol. 8, p. 294, 1885-86. Light Sense. In case of an occluded pupil, and of cataract, we manifestly are called upon to examine the degree of light perception. But dn disease of the retina and optic nerve, and in cases of ambly- opia it may also be important. Retinitis pigmentosa, hemeralopia, and nyctalopia are instances in point; and so is detachment of the retina. Opacity of the media cannot quench the light sense with a normal retina, nor can closing the lids do it. A rough mode of testing is by passing over the eye the shadow of the hand or of the outspread fingers, or by throwing upon it the light from the ophthalmoscope removed to a considerable distance. 1 Trans. Am. Oph. Soc, xvi. meeting, 1880, p. 142. 2 "Color-Blindness," Boston, 1880. 3 Archiv for Ophthal., vol. x., p. 1 GENERAL PHYSIOLOGY OF THE EYE. 31 In the latter method the patient is asked to state from what direction the light comes, which gives the projecting power, likewise. If an isolated spot of the retina is deficient in light perception we call it a scotoma, and if this be absolute, i. e., for white light, it is known as a positive scotoma; if it refer only to the perception, of colored light, as, for example, red, it is called a negative scotoma. The former implies reduced or absent form sense, the latter may be compatible with good visual acuity. Deficient perception at the periphery has been already referred to under perimetry. There is no recognized standard of normal light sense. The best known instrument for its examination is the photometer of Forster. It is a square box in which are placed black lines equal to Snellen LX, at one-third of a metre from the eye. A standard candle illuminates them and the degree of light is regulated by a window whose size is variable. When this window is two millime- tres square we have the normal minimum and it can be enlarged to 1500 square mm. Other methods, as by rotating discs, and by letters printed on gray backgrounds (Bjerrum), have been suggested, but for clinical purposes the simple methods above mentioned usually; suffice. The sensitiveness of the retina may be exhausted by exposure to very strong light, thereby producing total blindness. Leaving •out of view direct sunlight and the electric arc light, the retina will become fatigued by prolonged exposure to light of much less inten- sity, and for this reason an increase in the number of gas burners beyond a certain luminosity blunts the sensibility of the retina. Artificial light is inferior to daylight (certain forms of electric light •excepted) because it contains fewer blue and green rays. See remarks on p. 24. Subjective sensations of light may be referred to. They are produced by pressure on the eye, by the galvanic current as it is connected or broken, by effort of accommodation in the dark. These appearances are called phosphenes. In certain cases of choroiditis and retinitis subjective light phenomena, like coruscations or a dif- fused glow are very troublesome. With widely dilated pupils (my- driasis) a diffused red light sometimes appears. A similar blue color is sometimes seen by patients immediately after the extrac- tion of cataract. The retina retains the impression of light for an appreciable time and with some persons the duration is annoying. It varies from 3V to ^ of a second, and gives rise to the so-called after- 32 DISEASES OF THE EYE. images. These are in colors complementary to the quality of light received. Bright windows of painted glass excite phantom images of opposite colors. Rapid alternations of light and shade will excite in the retina sensations of color (Rood)1 at first green and with more rapid alternations, red. If we steadily gaze upon a very bright ob- ject and then close the lids, we have for a few moments a correct pic- ture of the object in its light and shade, a positive after-image; soon the reverse picture appears, which is the negative after-image, and it gradually fades. (See Leconte,2 Aubert.3) If in a dark room we look at a lamp through a pin-hole in a card, which we move quickly to and fro across the area of the pupil, we shall presently behold a phantom representation of the vessels of the retina. This phenomenon is called after the name of Purkinje, who first described it. It is caused by the displacement of the shadows of the retinal vessels cast upon the rods and cones as the angle at which the rays fall upon them quickly varies. It proves that the rods and cones are the percipient light structures; and the amount of parallax has been calculated, and the distance of the rods and cones from the blood-vessels deduced. The same ap- pearance can be produced by condensing on the sclera by a 2-inch lens the light of a lamp in a dark room, and moving it rapidly over a small surface. The Visual Purple. Experiments upon living animals, made first in 1876, by Prof. Boll, of Bologna, and subsequently pursued by Prof. Kuhne, of Hei- delberg, have demonstrated the existence of a pigmentary sub- stance in the retina, which is called the visual purple or visual rose. It is a secretion from the hexagonal pigment-epithelium of the retina. Its properties are summed up by Dr. Ayers (in the New York Medical Journal, May 1881, p. 582), who says, that it is an albu- minoid compound belonging to the outer segments of the rods and not to the cones. Its extraction requires a ten-per-cent solution of sodium chloride, or a two-per-cent solution of gall, and other steps which a foot-note describes. It is a photo-chemical substance, sen- sitive to light, and in man becomes bleached to a yellow hue. In some fishes, chiefly the deep-sea varieties, it is not changed in color by light, but remains purple. Its secretion in animals is increased by pilocarpine and muscarine. We know of no drugs or nerves whose action can diminish its quantity. When a person is for a long time kept in darkness, it becomes abundant; if bright light 1 "Modern Chromatics," N. Y., 1879. 2 " Sight," D. sTAppletonTN. Y 1882 3 Grraefe und Saemisch, v. iii. 2, p. 508. GENERAL PHYSIOLOGY OF THE EYE. 33 be admitted the eye is painfully dazzled. On the other hand, it is bleached by light to a yellow hue, and perhaps because yellow is the most strongly antagonistic to chemical rays of light, the retina is not suitably stimulated and we do not see well on first entering a dark room. The purple seems needful to the appreciation of dim light, and its conversion into yellow may be a defence of the retina against the injurious influence of very bright light. It is seen that the retina, in its chemical properties, bears out the analogy of the eye to a photographic camera in the most surprising and complete manner. Indeed, by confining rab- bits in darkness for a length of time and then ex- posing them to a bright window crossed by bars, decapitating them in a room lighted only by a so- dium flame, and treating the retina by a solution of alum, and in a manner similar to the usual pro- cesses of photography, a picture or optogram can be developed and fixed in the retina and preserved for future study. Such a picture is given in the diagram (Fig. 15) copied from the New York Medical Journal, March, 1881, and taken by Dr. Avers, who worked with Prof. Kiihne in his laboratory. It is natural to imagine that this remarkable substance has an important relation to sight, but we cannot define its functions, because it is wanting in the cones which give us the best vision. The yellow material which gives name to the macula lutea, lies in the front retinal layers and has nothing to do with the purple. It is impossible to discover the purple by the ophthalmoscope, and it has nothing to do with the red color of the living fundus, as has been proved by Becker in albinos. It has been proved also that animals whose retina has been bleached not only can see, but can distinguish colors (Kiihne).1 Note.—In the test series of Snellen the intervals from one line to the next are as follows: n • . 2J) 2^ 2_0 _2J 2JL 2JL _£0. 2_0 LI OOI ICts . X XV XX XXX XL LL LXX C CC Intervals: fJ-iiiViAiV The test types of Dr. John Green have less irregular intervals, but are by no means uniform. By the decimal system (Monoyer's) the interval between each line is ^ and the degrees go from 0.1 to 1.0. What in Snellen's series is written as f£ becomes 0.5, and from M to f£ we have five lines instead of three. We secure 1 " Handbuch der Physiologie," dritter Band, i. Theil —Gesichtssinn, 235 to 342,1879. See also an account by W. S. Ayers, New York Medical Journal, May, 1881. 3 34 DISEASES OF THE EYE. greater precision in determinations of vision, at the early stages of its decline, and also greater accuracy in correcting errors of refraction. For additional detail upon the physiology of sight the reader is referred to "Text-book of Physiology" by M. Foster; Part IV,, 1891, MacMillan & Co., sixth edition, CHAPTER HI. HOW TO EXAMINE THE EYE. A. We naturally first give heed to the external parts and we note the lachrymal sac, and press it with the finger; the lids— their edges, the cilia, the Meibomian follicles, lachrymal puncta, their cutaneous and their mucous surfaces, and they are to be turned over; the width to which the lids separate, their mobility—whether everted or inverted or thickened; the length of the palpebral slit; the cornea—whether transparent or blurred by opacity, its shape or curvature; the ocular conjunctiva—its color, the appearance of its vessels; the depth of the anterior chamber; the pupil—its size and mobility, its clearness; are both the pupils alike ? the iris—its hue and brilliancy—is it adherent to the cornea or to the lens ? is its periphery retracted ? is its tissue healthy or atrophied ? do both irides look alike? the crystalline—is it clear or smoky, or posi- tively opaque? Critical inspection of the cornea, iris and lens is of great impor- tance, and while marked lesions will be obvious enough, the finer changes in the cornea and lens demand special attention. This is true both of the cornea and of the lens. A good light and a fair exposure of the eye are to be secured, but great assistance is gained by resorting to two methods which are to be mentioned, viz. :• 1st. Oblique or focal illumination by means of a convex lens whose focus is about two inches. This may be used in ordinary day- light, the patient being at a little distance from the window; or, still better, the examination may be made by gaslight in a dark room. The lens is held about two inches from the eye, condensing the light on one side of it while the observer looks from the other side. The focus of the lens is made to play over the eye in all directions, deeper and more superficially as the various parts are to be exam- ined. The contrast between the intense light of the focus and the shadow which surrounds it constitutes the chief advantage of this proceeding. Caution must be used not to subject cases to this method which are likely to suffer harm by the strong glare, but experience will soon indicate what patients are not to be thus inves- tigated. For slight opacities or facets and in searching for foreign bodies upon the cornea, or for studying the iris and pupil, and for exploring the crystalline lens and anterior portion of the vitreous humor, oblique illumination is indispensable. 36 DISEASES OF THE EYE. One may also use a magnifying lens in addition to the illuminat- ing lens. Brticke's dissecting spectacles are extremely useful in giv- ing stereoscopic vision besides magnifying power. They consist of a pair of convex glasses of 12 inches focus combined with prisms of about 7°, set with the bases inward. 2d. Another device of value is illumination by a small plane mirror, reflecting a dim light. If we have no other than the mir- ror usually made for the ophthalmoscope, which is concave and of about seven inches fo- cus, it must be held at twelve or fifteen inches from the patient's eye to properly reduce the light. The examina- tion must be made in a dark room, the lamp placed about six inches behind the head, so as to leave the face in shadow. Viewed through the hole in the mirror, at the distance of a foot or more, whatever opa- cities may exist in the cornea or in the lens are easily revealed. By little tilting movements of the mirror the light plays over the eye, and if opacities exist they flit like shadows across the illumi- nated pupil. A shadow appears where, before, the surface looked transparent, and again a clear surface comes out as the shadow glides to another spot. The same phenomena occur when the cor- nea has lost its natural curvature, and has become conical or bulges in any manner. The shadows caused by irregular reflection some- times are very striking. More will be said on this point when we deal with diseases of the cornea and of the crystalline lens. Examine the tension of the globe by pressure with the finger— is it elastic, yet firm, like the normal eye, or too resisting, or softer than normal ? Does pressure cause pain, especially if made upon any spot of the ciliary region ? Ascertain if the cornea and con- junctiva, if touched by a fleck of cotton, or by a hair, exhibit their proper sensibility. Attend to the mobility of the eye, that its range of motion is sufficient in all directions, without tremor or spasm, or lagging" that the two eyes move in harmony, both for near and for distant objects, and in all directions. Whether there is apparent binocular vision, or if strabismus exist. A patient may volunteer the state- Fig. 16. HOW TO EA'AMINE THE EYE. 3T ment, that he sees double, which may or may not suggest itself by the behavior of one or both eyes, and there will follow the suitable method of inquiry about double images and muscular paralysis. Only by systematic use of prisms can this topic be fully considered. Protrusion of the globe on one or both sides will not be over- looked, and exploration of the border of the orbit with the finger, and especially of the foramina of exit of the supra-orbital and in- fra-orbital nerves, will not be omitted. In a great number of cases the examination will not go farther, because there is some obvious malady which demands immediate action and further inquiry is superfluous. Sometimes to accomplish what has been proposed will be diffi- cult, because pain or spasm of the lids or photophobia or fear, makes the patient refuse to permit a complete investigation. Es- pecially is this the case with burns and injuries, with cases of kera- titis and iritis and conjunctivitis. We may often gain our end by using a 4$ solution of muriate of cocaine several times within twenty minutes. At first it smarts, but soon it allays distress and photophobia and also reduces hyper- aemia. With children we may be obliged to employ anaesthetics, and my preference with them is for chloroform. In fact, I would use it rather than ether in many older subjects, when a brief inspec- tion or quick manipulation is the only requirement. The value of anaesthetics is greatly to be insisted upon in dealing with young children who have acute conjunctivitis and acute kera- titis. Not only are they spared the infliction of pain, but the eye is less likely to sustain injury. It is not necessary to give anaesthet- ics in every examination, but ofttimes efficient treatment can be practised in no other way. I once treated a child, aged about five years, for granular conjunctivitis, during nine months, and gave her chloroform about eighty times. She not only got well of the disease, but evinced no ill effects from the chloroform, either at that time or in her adult life. The great immunity of children from evil effects of chloroform is well known. B. We now give attention to the functional examination of the eye, and to the appearances to be seen by the ophthalmoscope. A functional examination includes, 1st, the acuity of vision, for which we need test types, and a box of trial glasses: 2d, the field of vision, for which we want a perimeter; 3d, the color sense and sometimes the light sense; 4th, we inquire into the function of the muscles as to their adduction and abduction, etc., both for par- allel axes and during convergence for the working point, and, 5th, we investigate the accommodation. When examining visual acuity we are obliged to correct errors of refraction, and to discover them we have various methods at 38 DISEASES OF THE EYE. command. The chief of these are the box of trial glasses, the ophthalmometer, and the ophthalmoscope. The first is to a great degree a subjective mode of examination, and liable to various sources of error. The second is purely objective, and if available is invaluable within its proper sphere. The third is also largely objective in its method, and if the observer is sufficiently expert he will often thus detect errors which trial glasses have either failed to discover or have reported falsely. For any knowledge of the deeper parts, viz., those behind the crystalline, we are wholly dependent on the ophthalmoscope. To this we shall next give attention, CHAPTER IV. THE OPHTHALMOSCOPE. The invention of the ophthalmoscope by Helmholtz in 1851, was the result of a careful study of the conditions which ordinarily prevent the pupil from emitting light from the eye, or wh}1- it looks black. He demonstrated that this accorded with well-known laws of optics, of which one is that light passing through a lens follows the same lines both when entering and wiien returning, in case any can return. Hence, with a pupil not larger than four millimetres, an emergent beam is very small and must go straight to the luminous source in a path so narrow, that an ob- server will not be able to catch it, without screening off the light with his head. If, as Loring has pictured, an observer look through a tube traversing a candle flame held close to his own eye, he can then catch light reflected from another eye. Helmholtz's de- vice was to reflect the light by a transparent mirror, consisting of three slips of plane glass. He set them at the angle of greatest polarization, so as to reduce the dazzling effect of reflection from the cornea. Ruete, in 1852, proposed a perforated metallic mirror. All the optical principles involved were fully discussed by Helm- holtz (see " Physiologische Optik," 1867), and it has been left to others to improve practical details and working instruments. The mirrors are either plane or concave. The latter usually have a focus of about seven inches; for special cases it may be shorter. The mirror need not be large, as Wadsworth has shown, for the useful part is very near the sight hole. The latter should be about 3£ to 4 mm. in diameter. Artificial light is commonly used, while by proper arrange- ments, sunlight can be employed. There are two methods of examination, viz., the direct and the indirect, or that with an upright image and that with an inverted image. In employing the direct method, it is obvious that the surface commanded by the eye of the observer will be most extensive if the mirror be as close as possible to the patient, just as we would peep into a room through the key-hole. To view satisfactorily the fun- dus oculi—supposing its optical structure normal or as it is called 40 DISEASES OF THE EYE. emmetropic, and with its accommodation suspended—the observer must put his own eye into a state for reception of parallel rays, i. e., look as if the object were far away, notwithstanding he knows it is only about an inch distant. He can use but one eye ; what the other sees must be disregarded, or it must be closed. The practical details are as follows: We darken the room and use a single light—an Argand gas- burner or a student's lamp. The object to be sought for is the optic disc, and the patient is bidden to look straight forward, while the observer looks in from the temporal side at an angle of about 15°. For the examination of the left eye the observer's left is used, and for the right eye the observer's right; the place of the lamp Fig. 17. being shifted and the instrument put into the corresponding hand; the observer comes as close to the eye as possible, and this may be within one inch or even within fifteen millimetres. If now the eyes of both be normal in refraction, and in both the accommodation be entirely at rest, the details of the eye-ground will be easily seen. The other method, called the indirect, or by the inverted image, is as follows: the observer holds the mirror twelve or fourteen inches from the patient, and brings before the latter's eye, and within two inches of it, a biconvex lens of two and one-half inches focus. This lens condenses the light from the mirror, and also collects the emergent light into an inverted image which lies at about two and one-half inches from the lens, between it and the mirror. The observer examines this aerial image, and not the eye. It is bright, small, and covers a larger surface than is to be seen with the indirect method, and shows better the relation of the parts. THE OPHTHALMOSCOPE. 41 To know whereto direct the light, the observer should keep both his eyes open, and rest the upper edge of the mirror on the inner end of the brow. When he has thrown it on the eye, he will be attracted and embarrassed by the reflection from the cornea. This annoyance is greatest when the region of the macula is under in- spection. One learns, after a time, to look beside this reflection and ignore it. When using the indirect method, the biconvex lens furnishes in addition two reflections of the mirror as small, round spots, and these are gotten out of the way by giving it a slight in- clination. In this kind of examination the corneal reflex sometimes seems to cover the whole field. A little change in the position of the lens or mirror will remove it. Fig. IS. The direct, method of examination presents fewer difficulties of instrumentation than does the indirect method, but it offers a more complicated problem than the other, because the refractive condi- tion of the eye must be determined, and, if erroneous, must be cor- rected by proper glasses before the inspection of the fundus can take place. What in the beginning is a difficulty, becomes, after a time, a most valuable quality of the direct method. What is the extent of field and what the magnifying power by these respective methods ? It is assumed that both observer and observed have normal eyes, whose nodal point is 16.6 mm. from the retina. With the direct method the extent of field may be thus stated: If the observer could make his own nodal point coincide with the antei'ior principal focus of the patient's eye, he would have a field equal in size to the patient's pupil. This would bring the eyes within about 7 mm. of each other, which is not feasible. At 15158 i2 DISEASES OF THE EYE. the nearest approach, with a pupil of 4 mm. we have a field of about 2 mm. or practically what covers the diameter of the optic disc. Another limitation is the size and form of the light employed. We see its image on the fundus long and narrow, and the bigger it is, the larger the illuminated space. It follows that we can view only a very small portion of the fundus at a time. The magnifying power will be that of a lens about 15 mm., or j inch focus, and the distance from the eye is unimportant. It may be stated in terms of angles or by a conventional linear standard. By the former it will be 5° 43% by the latter, taking 10 inches or 250 mm. as the distance of distinct vision, it will be 15 times, if we take 12 inches or 300 mm. as the standard, we have 18 times magnifying power. By the indirect method the extent of field is determined by the diameter of the objective lens and its focal length; the latter being the more important. If this be 2\ inches or 60 mm. focus, and the diameter be 1^ inches or 30 mm. the ex- tent of field will be 8 mm. diameter. This, however, is not realized because of the shape and size of the gas or other light. It amounts to about 5 diameters of the disc. Magnifying power is also deter- mined by the focal length of the objective lens. With one of 2£ inches, we have about 4 times, with a lens of 3 inches we have 5 times. That is, the weaker the lens the greater the amplification; at the same time the smaller the field. Intensity of illumination is brighter with the indirect than with the direct method. To be prepared for the various refrac- tive errors which will be met, and also to correct such as may belong to the ob- server, a series of convex and concave glasses are placed behind the mirror. In the early instruments these wrere few in number and the mechanical parts simple. But as the value of the instrument in diag- nosticating refractive errors became more fully appreciated the number of glasses has been increased and the mechanism for them THE OPHTHALMOSCOPE. 43 more complex. No one has cultivated this kind of improvement more successfully than Loring, yet there are many other good de- vices, by Couper, Nettleship, Jackson and others. A moderately com- plete set of glasses is indispensable, even though accurate diagnosis of refractive errors is not sought. Without them one will often be limited to the use of the inverted image in studying the pathologi- cal changes of the fundus. In medical ophthalmoscopy this would be a serious hindrance to a just appreciation of changes in the optic nerve and retina. Fig. 19 shows a simple style of instrument Fig. 20. with 8 concave and 7 convex lenses. Still another, by Loring (see Fig. 20), gives 24 concave and 23 convex by interposing a quadrant on which are strong plus and minus glasses, and the series is still farther enlarged by using what are called half numbers. Another arrangement has been introduced by the writer to en- able an observer to command the series of lenses without removing the instrument from his eye. This is done by cog-wheels playing upon two discs which contain the lenses, and besides a full series of spherical glasses, cylindric glasses from the spectacle box can be inserted in a spring clip. See Fig. 21, p. 45. 44 DISEASES OF THE EYE. A long handle is a decided convenience unless a patient is in bed, when the ivory portion may, if needful, be unscrewed. Another form of ophthalmoscope is the binocular (Giraud-Teu- lon) which gives stereoscopic effect and is available only for the inverted image. It is seldom employed. There are fixed or dem- onstrating ophthalmoscopes, Liebreich, Cusco, etc. Burke substi- tuted a concave mirror for the convex lens in getting the inverted image and gains greater magnifying power. In learning to use the ophthalmoscope, the first requirement is that both parties lay aside all efforts of accommodation. The pa- tient usually does this, because he has no object to inspect, and his eye is dazzled by the glare; yet too much dependence cannot safely be placed on this assumption, as will be dwelt upon hereafter. The inexperienced observer never does this, but looks as he always would at a near object, and not as he would at a distant one—in other words, he calls in play his accommodation. To prove this and to enable him to see, he may, when using the direct method, put behind the mirror a concave glass of 10 inches focus. Then he will see the bottom of the eye, just as he would read a book ten inches away. But let him weaken this glass to 20 inches, and again he will see; and then to 40 inches, and perhaps he still will see. His problem is to see clearly, without any glass and with no effort. He must cultivate this habit. Let him practise looking with a convex glass of 8" focus before one eye at a page 7£ inches away, or as much farther as he can read, keeping the other eye open. He will finally find whether he can, at pleasure, utterly abando'n accommodation, or what fraction of it he is obliged to use. What- ever that may be, he is to allow for it as his personal equation of error. If, however, the observer do not have normal eyes, he must put behind the mirror the glass which corrects his sight for dis- tance, plus or minus the glass which his habit of accommodation compels him to employ. Then he is in position to examine abnor- mal eyes. In doing this he will have to add to his correcting-glass, or subtract from it, the glass which corrects the error of the pa- tient's eye. On a later page a slight modification of this statement will be made, and more details mentioned. The following method of conducting an examination is suggested as being sure to cover all the points of a case. First, illuminate the eye with the mirror from a distance of six- teen or eighteen inches, and let the light play from side to side over the cornea. This will show opacities in the cornea or lens and the degree of luminosity of the fundus. If the eye be of decidedly ab- normal refraction or ametropic, retinal blood-vessels will be visible. They may indicate that the eye is either near-sighted or far-sighted. If the former, the vessels will move in a direction opposite to the THE OPHTHALMOSCOPE. 45 Fig. 31.—The mirror, besides swinging in the trunnions, may be rotated in a circular direction and thus assume any angle. The front disc is moved by the lowest wheel and the back disc by the upper and exposed wheel. There is a spring clip on the back of the instrument to carry a cylindric glass. In other particulars the instrument is copied after Dr. Loring's latest model. It gives command of a complete set of spherical glasses, both positive and negative, amounting to seventy-six in number, and cylindric glasses may be inserted at pleasure from the spectacle-box. 46 DISEASES OF THE EYE. motion of the observer as he moves his head from side to side, while for far-sightedness the vessels will move in the same direction with the motions of the observer. Having this preliminary idea of the state of the eye, the bicon- vex or objective lens may then be put up for the inverted image. The lens is held by the thumb and forefinger, while the little finger takes a support on the edge of the temple. To find the nerve, say in the right eye, let the patient look at the observer's left ear and vice versa; or look straight forward while the observer moves 15° to the temporal side. The lens is to be moved a little from side to side, which of course carries the image with it; and it will be noticed that parts upon deeper planes, as in the case of excavation of the optic nerve, have a greater range of movement than do the more superficial parts. For instance, the edge of the nerve will move less extensively than its bottom if there be excavation. The little finger may be allowed to press on the eye, at the same time lifting the lid, and thereby determine whether a little increase of tension will cause pulsation of the retinal vessels. After inspect- ing the nerve, the patient should be directed to look in every direc- tion, to bring all parts of the eye-ground into view. The region of the macula will also be noted, although this will often not be well seen unless the pupil has been dilated. Next, the eye should be inspected by the upright image, the ob- server coming so close to the face as even to touch it, and bringing the light to the requisite position to permit close approach. Now, it will be needful to put behind the mirror such glasses as neutral- ize refractive errors, and the details of the fundus will be more fully appreciated, besides learning what is the state of refraction. I do not mean to be understood as intimating that the diagnosis of the state of refraction will easily be made by the beginner—on the con- trary, he will meet not a few difficulties; yet these may be sur- mounted by moderate ability and perseverance. After having studied the bottom of the eye, a strong convex lens, say of three inches focus, may be put behind the mirror to enable one to inspect the crystalline, the anterior part of the vitre- ous, and the cornea, the patient being told to look in different direc- tions, to throw into view the periphery of the lens or vitreous opacities not in the field. It will be well to turn down the light to get a view of very faint opacities in any of the media and one will look from various distances, by doing which the magnifying power will be altered. Finally, turn the patient to face the light and use the focal illumination already described (page 36). Of course re- gard must be had to the sensitiveness of the patient's eye and* its liability to injury by intense light. Very rarely does any result, and this is specially true of lesions of the optic nerve, retina and THE OPHTHALMOSCOPE. 4? choroid. In very many cases, only the direct method need be used, and to the fundus as thus seen we will now call attention. The Fundus Oculi as seen by the Ophthalmoscope, and espe- cially by the upright image—The larger the pupil the easier and more complete will be an examination, but one will seldom need to use atropia. If mydriasis is required, a 4$ solution of cocaine will usually give sufficient enlargement in 20 or 30 minutes and it passes in a few hours. The object first sought is the optic nerve, which appears as a circular disc on which the retinal vessels are seen. For the recognition of the anatomy of the nerve compared with its ophthalmoscopic picture see Fig. 22. Its color varies from pinkish-white to deep red; often the whole surface is not of the same hue, a part being red and the rest pale, and this may be respectively the nasal side contrasted wTith the temporal side, or the circumference contrasted with the centre. The whiter parts reflect light more brilliantly because they are sunken and concave, and the paucity of fibres in the depressed part favors the penetration of light to, and its reflection from, the lamina cribrosa. The depression or so-called excavation often found in the nerve may be central and small, or in extent it may exceed half its diameter:—it may be a slope on the temporal side, or more rarely downward; or the outer half may be almost flat and below the level of the inner, like a step. The nerve is sometimes a true papilla, and the highest part may be central or on the nasal side. In all cases the tissue is translucent, so that one looks through a depth of substance, and the limit of inspection is the lamina cribrosa. The latter when seen is densely white, and is often mottled with dark spots. As the nerve-fibres come through its meshes, they lose their neuri- lemma and become transparent axis cylinders. The nerve is some- times oval, with its long axis vertical, and, even when truly circu- lar, may by reason of astigmatism seem to be oval in any direction. It sometimes has an irregular outline. The border is well defined, being sharply cut by the edge of the choroidal aperture, and often a black pigment deposit extends more or less about it. Sometimes the choroidal opening is appreciably larger than that in the sclera, and a narrow ring of the latter is to be observed. If the optic fibres are heaped together in a certain space, they will be easily recognized as they cross the edge of the disc and extend into the retina, sometimes to a considerable distance. In eyes deeply pig- mented, the optic nerve is always by contrast more red, and the nerve-fibres are more distinct. Sometimes they make a complete fringe or aureole of hair-like radiating lines. The conspicuous feature of the nerve is the network of vessels which appear upon it. They emerge and enter near its centre, and present many varieties of arrangement and subdivision. A single 48 DISEASES OF THE EYE. arterial trunk usually comes up from the bottom of the disc and sends branches above and below, the veins taking a course nearly parallel with the arteries. It would be useless to attempt to de- scribe all the varieties which the vessels present. The diagram from Leber (Fig. 23) gives the vessels and their nomenclature. Besides these main branches, there are many finer twigs Avhich pass from the nerve in the horizontal meridian, and they are most numerous on the temporal side. The number of the vessels on the disc is exceedingly various, and sometimes they spring forward in large curves and take a sinuous course, or may even curve around each other in complete or par- tial spirals. Such pecu- liarities will have relation to the vascularity of the general system, and due allowance must be made. Sometimes the walls of the arteries are of unusual thickness for a certain distance beyond the disc, and then they have a whitish border. At the region of the yellow spot there are never any large vessels, but it will be seen that from the transverse branches above and below numerous small twigs are sent down which run almost to the fovea. So fine are these that for a long time it was declared that the region of the macula was the most poorly supplied with vessels. This, however, is erroneous, as has been shown by Nettle- ship, Becker, Loring, and others. Nettleship says: " On comparing different parts of the retina, I find that while in an area of 5-gVo square inch> in the yellow spot region, forty complete capillary meshes can be counted, not more than from six to nine are included in the same area at a spot -^ inch behind the ora serrata, the injec- tion being equally complete in both places. The area of the fovea centralis, which is destitute of vessels in the specimen here figured, is equal to about ^Vir square inch, and is irregularly oblong. It is scarcely larger than the single capillary meshes at the ora serrata." Fig. 22.—i, Internal sheath of optic nerve; e, e, external sheath of optic nerve; v, the intervaginal space; I, lamina cribrosa; c, c, posterior ciliary arteries; S, S, sclera; Ch, choroid; R, retina; t, T, tendinous or scleral ring; p, P, choroidal ring; C, optic papilla. THE OPHTHALMOSCOPE. 49 Another frequent anomaly is that a vessel may come out at the margin of the optic nerve, or at a point beyond the margin, and go back to the retina. These have been called cilio-retinal vessels (see Nettleship: " Royal London Oph. Hosp. Reports," vol. ix., part 2, p. 161, December, 1877). Mr. N. found one such vessel in a micro- scopic examination of the optic nerve, and proved that it passed from the sclera, at the level of the lamina cribrosa, into the nerve and to the retina, and such vessels seem in all cases destined to the supply of the region of the macula lutea. The opportunity of see- ing them is most often given in the choroidal crescent of myopic eyes. Fig. 23.—Blood-vessels of the Retina, ans, Arteria nasalis superior; ani, arteria nasalis inferior; ats, ati, arteria temporalis superior and inferior; vns, vni, vena nasalis superior and inferior;yes, vti, vena temporalis superior and inferior; ame, vme, arteria et vena mediana; am, vm, arteria et vena macularis. The retina is to a slight degree discernible as a tissue, notwith- standing its transparency, and near the disc its optic nerve-layer usually appears, with greater or less conspicuousness, as fine hair- like lines radiating from the margin. Above and below they are most marked, and they cluster around the principal vessels. The visibility of the retina, as wTell as the tone of the fundus, depends chiefly on the quantity of pigment in the epithelium and m the choroid. In blue-eyed persons the retina seems very transparent, and the fundus of a brilliant red. In dark-eyed, and especially in dark-skinned persons, negroes, Indians, etc., the retina seems opal- escent, and the hue of the fundus is dull, and of a dun or tan color. 4 50 DISEASES OF THE EYE. The pigmentation is always deepest about the central region, be- cause the epithelium is more saturated, while the remoter parts permit the choroidal vessels to be seen as light-red stripes with ir- regular islets of pigment. The surface of the retina sometimes shows a flashy, silvery reflection, which glances along the vessels and plays about the macula lutea. It alters in place and form, on the slightest movement of the eye or of the mirror, and the spot which it has left has a perfectly normal look. This is seen in dark eyes and in young children most frequently. It is not pathological. Another phenomenon is a circle which sometimes appears at the middle of the fundus, around the fovea as a centre, and has a diam- eter varying from one to two discs, as seen by the upright image. This is also visible by the inverted method, and is evidently an annular reflection. Probably in these cases the source of reflection is the membrana limitans. The reason why the macula should be the special seat of such appearances is its convexo-concave surface. The fovea centralis often shows as a small glistening dot, more or less completely circular as the light plays over it. Its concavity favors its action as a reflector. In a myopic eye, where this was seen, I have observed it to be most brilliant before the perfectly correcting glass was employed, and that when this was used it dis- appeared almost entirely. It has been said that the arteries of the retina are smaller and brighter than the veins. It must be added that they exhibit a well- defined line of light along their centre, which, in the veins, is much less conspicuous. This is an optical effect whose cause has been disputed, and a most valuable paper upon it was published by Dr. Loring in Tr. Am. Oph. Soc., 1873. That it is due to the refractive action of the column of blood in the vessel condensing the light which passes through it and is again reflected from the underlying surface, has been proved to myself by two cases. In one of them there was an effusion of blood beneath the choroid, which made a dark patch. This was crossed by a vein on which no light-streak was present while it traversed this dark surface, but where situated upon the normal choroid, the usual streak was distinct. As the blood-patch became absorbed and a white scleral surface came to view, which was caused by rupture of the choroid, not only did the vessel recover its usual light-streak, but this became much more decided than upon the adjacent portions of the vessel. A second case bearing on this point was one of extreme colloid deposit upon the choroid, having all the brilliancy of the most marked patches of fatty degeneration, as found in albuminuric retinitis. This glitter- ing surface was about two discs long and one disc wide, and was behind one of the transverse retinal arteries. As the artery crossed this spot, the whole vessel was a bright ribbon of light—the central THE OPHTHALMOSCOPE. 51 streak being intensified and widened so as to equal the diameter of the vessel. On either side of this spot the artery had the usual appearance. It is therefore evident that the light-streak depends chiefly on the reflecting properties of the surface over wrhich the vessels pass, and on the nature of the blood-column. That some reflection comes from the surface of the vessel is true, but it is ex- cessively slight, as proved by my first case while the blood-patch was fresh and dark. The " light-streak" is, therefore, a phenome- non of refraction and reflection, and the light must pass through the vessel from in front and penetrate to the sclera, to be then re- flected from the latter and again acted upon by the blood-vessel, which condenses it into the bright, luminous streak. This is essen- tially the view first announced by Loring (see " Trans. Amer. Oph. Soc," 1881). Davis coincides with Loring's explanation, having re- peated his experiments by letting the blood from the carotid of a cat flow through fine glass tubes (Arch, of Ophth. XX. 1., 1891). Story discusses the matter, and agrees with an opposing theory of Schneller, ()]>hthal. Review, April, 1892; while Dimmer is quoted by Story in favor of a totally different theory, viz.: that the reflex in the veins is from the surface of their blood column, and in the arteries is from the axial part of the blood stream (Ophth. Review, May, 185)2). My observations above quoted have not been noticed by the writer mentioned, and my views remain unchanged. Pulsation of the veins upon the optic disc is quite common. It is explained by Donders as the effect of the arterial tension com- municated to the veins through the vitreous, and causing pulsatory movement on the optic disc, because here the column of venous blood is just escaping from the intraocular pressure. It is most apt to be seen when the veins are large. Schoen was able to study this in a patient whose pulse was only 16 to 23 per minute. He concluded that the venous pulse is merely the effect of the pulse of the artery upon the vein as the two vessels lie in juxtaposition in the optic nerve.—Klin. Monatsbldtter (Zehender), Sept., 1881. Pulsation of the arteries occurs when the intraocular pressure rises to an abnormal degree, or in cases of disease of the heart (aortic valves) or large vessels, and under some other morbid circumstances. Pulsation of both arteries and veins can always be caused by pres- sure with the finger, and, if it be made very strong, the circulation can be entirely suspended. In observing the fundus closely, if the tissues are normal and the refraction perfectly corrected, the retinal epithelium is seen as a granular surface, like the finest emery-paper, and its molecular look is perfectly distinct. A few glistening dots are sometimes seen near the macula, which appear to have no special importance. 52 DISEASES OF THE EYE. The fovea centralis is always the most difficult spot to examine, especially with undilated pupil. It has a dull, red look, or majT re- turn, as above stated, a gray reflection, which may be a partial or complete ring, which flickers at the slighest movement, and is about one-fourth or one-sixth of a disc in diameter. In young persons it is widest and most distinct. The very centre is so deep in color as to be almost brown. The degree to which the choroid can be seen varies with the pigmentation of the «ye. In albinoes the vessels are visible, even about the macula. In greater degrees of pigmentation, some ves- sels may appear between the nerve and macula, and in all persons they are distinct at the eccentric parts of the fundus. They are of a light pink hue, appearing like flat stripes, and have a curvilinear arrangement and interlacement in distinct meshes. No distinction can be made in them between arteries and veins. Sometimes the place of beginning of the venae vorticosas is recognizable. Between the meshes of the choroidal vessels the pigment-stroma is seen in more or less dark patches of irregular shape. The visible choroidal vessels are always broader than the retinal trunks. Immediately around the optic nerve the choroidal pigment is often quite abund- ant over a considerable breadth of surface, and, as above said, the central part of the fundus is overspread with a uniform layer, which usually completely hides the choroidal vessels. For verification of above description, see colored plate at the back of the book. CHAPTER V. GLASSES. As we shall have to consider the proper use of glasses in correct- ing errors of accommodation and refraction, we may say a few words in general upon their varieties and properties. We have to deal with glasses of spherical curvature which are convex or concave, and we have glasses of cylindrical curvature, also convex or concave. We also have glasses whose surfaces are plane, but not parallel to each other, viz., prisms. Very exception- ally glasses ground to a hyperbola have been used. In spherical glasses we have the following forms: The convex are called positive or collective or magnifying glasses, and are denoted by the sign +. The concave are called negative or dispersive or minifying glasses, and are denoted by the sign —. The focus of a glass is the place where the rays from a given object Fig. 24. cross each other on the axis of the glass. For parallel rays the place of crossing is called the principal focus, and this is understood when no adjective is used. If an object be near enough to the lens to emit diverging rays, these, if they cross, do so at points called conjugate foci. For convex lenses the foci are real and positive, and on the side of the lens opposite to the object. For concave lenses the foci are negative, imaginary, or virtual, and on the same side with the object. But for convex glasses, if the object be situated at the principal focus, the rays after passing the lens will not con- verge, but be parallel; hence there will be no focus. If the object come still nearer, the rays will be divergent, and the focus virtual. For concave glasses the rays become more divergent as the object approaches the principal focus, and at this point rays cannot pass through, because the divergence becomes too great. In Figure 24, 54 DISEASES OF THE EYE. we have the principal forms of lenses, viz.: the plano-convex A, the biconvex B, the convex meniscus C, also the plano-concave D, the biconcave E, and the concave meniscus F. The first three are all positive, and the last three are all negative lenses. The biconcave and biconvex are supposed to have curvatures the same on each side, but this may not be, and frequently is not, the case. Images from plus (i.e., convex) glasses are inverted and smaller, if the object be beyond the principal focus. If the object be at the principal focus, no image is formed. If it be nearer than the prin- cipal focus, the image is not real, but is virtual and erect, and larger than the object; the lens then becomes a magnifier (loupe). Im- ages from minus (i.e., concave) glasses are always small, erect, and virtual, provided the object be farther than the principal focus. If an object lie at or nearer than the principal focus, no image can be formed. Cylindric glasses are ground by a cylindric tool, and have a curve whose maximum is at right angles to the axis of the cylinder, Fig. 25. while in the direction parallel to the axis there is no curve. Such glasses cannot form images, although they may be said to have foci according to the laws of spherical lenses. Cylindric glasses are shown in Figure 25 and represented with square outlines. In practice they are cut oval like other glasses. The axis is shown to be along the middle of the curve and parallel to the vertical edge. The Arrangement and Nomenclature of Glasses.__Formerly no better aid could be had in choosing glasses than the advice of the optician from whom they were purchased. At present, oph- thalmic surgeons find their function to consist largely in advice upon this subject. They require a trial-case more or less complete, which must contain spherical and cylindric glasses, both convex and con- cave; also prisms from 1° up to 20°, and a suitable frame. A slip of red glass and an opaque screen are usually added. In giving numbers to glasses it was formerly the practice to do so upon the assumption that the index of refraction of the material was 1.5 (3) GLASSES. 55 and, for a double convex or double concave glass both whose curves were alike, the focus was found by the rule that the focus was equal to the radius of curvature.1 Another embarrassment is the want of uniformity in the inch measure among different nations. The following are samples: the English inch is 25.3 mm.; the Austrian is 26.34 mm.; the Prussian is 26.15 mm.; the Paris inch is 27.07 mm. Between the English and the Paris inch the difference is ^. In the numbering of glasses, therefore, two things needed to be readjusted: first, the error aris- ing from regarding the radius of a bi-spherical lens as the equiva- lent of its focus, and vice versa; secondly, the discrepancy as to the standard measure. The latter objection is overcome by abandon- ing the use of inches and employing the metric system of expres- sion. The first difficulty is obviated by numbering glasses accord- ing to their refractive power and not according to their focus. Refracting power is the reciprocal or inverse of the focus. Thus, a lens of 30 inches focus has a refractive power of ■£$. This frac- tion may be expressed in decimal form and it becomes .033. A lens of 20 inches focus has a refractive power of ^, or .05. A lens of 4 inches focus has a refractive power of \, or .25. The glasses in actual use began at the numbers with long foci, and came down to those of short foci—that is, from the weak to the strong; but there was no regularity in the progression; no com- mon interval was observed (see column 1 of the table on page 57). Now, for purposes of scientific study, and for convenience in exami- nations, regularity of interval is highly convenient. Attempts have been made to secure this desideratum, and various intervals have been suggested, viz., the fractions $\w, T|- *V> iV When, however, the metric measure was substituted for the inch, it was also resolved to establish a metric interval which should become the unit of measure and the standard of gradation between num- bers. Facility in calculations, and uniformity, both in gradation and in nomenclature, were the objects sought. The unit is a glass of one metre focal length, which in English measure equals 39.37 inches, and is called a dioptry (French dioptrie) (D). In French measure it would be 37 Paris inches. But this interval is too great, and therefore the metre is again divided into fractions. By the old 1 This results from the formula F=2 / • in which F stands for focus, r for radius and n—1 for index of refraction. If now r=12 and w=1.5, the formula becomes F—2(15_1)=1I8-=12, that is, the focus is equal to the radius. It turns out that the glass now in use does not have the index 1.5, but a higher degree varying between 1.52 and 1.55 (Nagel). Javal assumes it to be 1.54. If we substitute this in the formula, we have F—2 (1'^ =^^=11.1. That is, the focus is less than 12 inches, and very nearly 11 inches. 56 DISEASES OF THE EYE. method a lens was known by a number which was its radius of curve, and this was assumed to be the same as its focal length. It is now known by its refractive power, and this is expressed by the number of dioptries contained in it. It is seen that a metric mea- surement of glasses may be quite distinct from the system of diop- tries. But, where the metric system has been adopted, the dioptric interval has also been accepted. Nagel gives in Graef e and Saemisch (B. VI., p. 310) the mode of converting the old into the new system of measure. He assumes the index of refraction at 1.528, which is German glass, and with this he finds the equivalent of a dioptry to be 41.5 English inches. If the index be that of French glass, at 1.54, the dioptry becomes 42.5 English inches; with index of 1.53 it becomes 41.7 English inches. Nagel proposes that, in transmuting the old to the new system, 40 inches be taken as the equivalent of the dioptry, and with this Javal concurs, the error not being very large. Therefore, an 80 inch glass =0.5D : 40"=1.D : 20" =2.D: 16" = 2.5 D : 10' = 4D. The table on the next page, modified from Mauthner, gives a sufficiently complete series, and according to both systems, accepting 40" as the dioptry. It is seen that at the upper end of the scale the interval between glasses is small, viz., 0.25 D, but that beyond 3.5 D (11 inches) the interval is .5 D, and again becomes still greater. The reason for a large interval among the strongest glasses is that a slight alter^ ation in their distance from the eye greatly modifies their refract- ive value, and any little change can be thus effected. The special advantage claimed on behalf of the dioptric system is the ease with which calculations can be made in adding and subtracting lenses. For instance, put two positive lenses, + 2 D and -4- 3 D, together, and their result is -j- 5 D. If + 3 D and —ID are united, + 2 D re- sults. If — 4 D and —2D unite, — 6 D results. One need only deal with simple numbers, and remember the effect of the precedent signs of + or —. If lenses are to be united which are designated only by their foci, the calculation must be made in fractions, viz., + 3 D and + 1D, become TV+iV—o-=tV- A lens of six inches focus added to one of twelve inches focus £ + iV=i« The use of the system of dioptries makes calculations simple, but it is a mistake to imagine that it makes any practical difference in selecting glasses. We are compelled to take what the patient actually needs, and whether we express ourselves in terms of diop- tries, or of focal length, or of refractive power, is not of strenuous importance. Certainly one dioptry is too large an interval, a half dioptry is often too small, and we may be obliged to choose glasses which do not come under this rubric at all. The essential thing is to know the real refractive worth of our glasses, and whether we reckon it in dioptries or by other means is indifferent. GLASSES. 57 Focus in Number in Focus in Number in Inches. Dioptries. Inches. Dioptries. 160 0.25 14 2.75 80 0.5 13 8. 60 (0.67) 12 3.25 50 0.75 11 3.5 40 1.00 10 4. 36 (1.11) 9 4 5 30 1.25 8 5. 24 1.5 7 5.5 (22) 1.75 6* 6. 20 2. 6 6.5 18 2.25 5* 7.5 16 2 5 5 8. The above table shows the glasses according to the old enumer- ation in English inches and their equivalents in dioptries. We give below the dioptric series and its equivalent in inches. Inches aj'prox- Indies approx- "nches approx- Dioptries, D. imately. D.optries, D. imately. Dioptr es, D. imately. .5 80 3.5 11 11 31 .75 50 4. 10 12 3* 1. 40 4.5 9 13 3 1.25 30 5. 8 15 2| 1.5 24 6. 64 16 2* 1.75 22 7. 5* 18 2i 0 20 8. 5 20 2 2.5 16 9. 44 40 1 3. 13 10. 4 Attempts have been made to make available a fewer number of glasses than the list above given, by using a spectacle-frame which may carry simultaneously a combination of three for each eye. Dr. E. G. Loring, jr., and Dr. John Green, and Dr. Roosa, have gotten up such a series, and where cheapness is more to be regarded than convenience it will answer the purpose. It must, however, be admitted that three glasses put in the place of one single glass will not in practice be the same, however correct the calculation, because by six reflecting surfaces the loss of light is three times greater than by two surfaces, and for strong glasses allowance must be made for their respective distances from the nodal point. If, however, the choice lies between an abridged series and no spectacle-box, the former alternative is much to be pre- ferred. Such a box is sold by Meyrowitz Brothers in this city. The power of glasses depends not only on their focus, but on the distance at which they stand from the nodal point. This varies according to the depth of the globe in the.orbit, and the height of the nose, and the kind of frame. When, however, a glass is worn at the anterior focal distance of the eye, which is about 13 mm. Focus in Number in Inches. Dioptries. 44 9. 4 10. 3f 10.5 34 11. 34 12. 3 13. 24 14. 24 16. 24 18. 2 20. 58 DISEASES OF THE EYE. from the cornea, it has the least influence on the size of the retinal image—an important fact first pointed out by Giraud-TeulonJ and later by Knapp. But moved to any other place its influence is im- portant. At this position the visual angle is not altered, but the linear dimensions are changed. Usually the distance is about £ inch, or 2 cm. This is to be added to the power of a convex lens and subtracted from the power of a concave lens. The practical im- portance of this fact is chiefly felt among the stronger glasses. One who wears a glass as high as + -§- finds that by slipping it down upon the nose it becomes stronger, and with persons who use cata- ract glasses this manoeuvre is often of advantage. On the other hand, if a "deep" concave glass is worn, say—\, its power is dimin- ished by holding it away from the eye, and increased if pushed Fig. 2G. nearer to it. When discussing errors of refraction, reference will again be made to these points. The frame in which trial glasses are placed is not an unimpor- tant matter. There are many contrivances: some very elaborate and likewise heavy. A pattern made by Nachet in 1866, and which is now made by G. Tiemann & Co., New York, has served me for more than twenty years with great satisfaction. Its various ad- justments are readily understood (see Fig. 26). Bi-cylindric glasses are sometimes employed in lieu of bi-spheri- cal lenses when very high numbers are required, as, for example, after extraction of cataract. They give a flatter field and less aberration. In case a cataract glass must have a cylindric surface amounting to two or more, perhaps as many as six dioptries, one surface may be composed of the cylindric convex surfaces with their axes at right angles, and the other surface may be spherical An illustration is the following: a glass -f 11.D.C+ 6.DC 180° is resolved into + 5.DS C + 6 Dc 90° + 12.DC 180°. That is because in one meri- 1 Annales d'Oculistique, Sept., Oct, 1869. "------ GLASSES. 59 dian + 17 D and in the opposite + 11 D being called for, the differ- ence of 6 D is thrown into one surface by employing cylinders at right angles of + 12 D and 6 D, leaving for the opposite side 5 D (17 — 12), to be thrown into a spherical form. Such a lens is called " toric;" it is much thinner than the usual sphero-cylinder, gives a flatter and more correct field, a wider visual angle and better vision. The discussion of toric lenses is found in an article by Dr. John Green (Trans. Am. Ophth. Soc, 1890, p. 708). They are manufac- tured by a few opticians in Philadelphia and New York. Prisms used in ophthalmic practice are of only moderate angle, usually below 6°, rarely as high as 10°. Rays passing through them are deflected toward their base, and the apparent position of an object is shifted toward their angle. The least displacement occurs when rays fall perpendicularly upon the surface, and because this is plane they are not collected to a focus and do not form images. Some dispersion and decomposition of light takes place, and in direct ratio to the angle of incidence. For prisms of small angle the degree of displacement is equal to half the angle—and until recently they have been designated sim- ply by their angles. Another nomenclature has now been proposed to put them in harmony with the system of numbering other glasses, viz., according to their effect, and not according to their construction. The degree of deviation is found by combining a prism with a convex lens, and meas- uring the amount of displacement of the image at the focal plane. In the following table taken from the report of a committee (see Trans. Am. Ophth. Soc, 1888, p. 151), the dis- placement is given both in degrees and linear measurement (the sine or tangent of the angle, which for small angles are the same). It is proposed to number prisms simply by the figures of the first column, leaving out of view their angle and the index of the glass. A further development of the idea is the prism dioptry of Prentice (Archives of Ophthalmology, XIX., 1,75, and XIX., 2 and 3, p. 128), in which the unit of measure is a prism which shall cause a tangent deflection of 1 centimetre at the distance of 1 metre, and this prism, P.D., becomes the multiple of the scale. Its angular value can be deduced from the preceding table, which is calculated for one-half the distance—and 1 P.D. will be very nearly a prism of 1°. But Mr. Prentice as a practical optician declares that he has found Angle of Deviation. Angle of Refraction. Linear Displacement at 0.5 metre. 0.5 0.93 4.3 mm. 1. 1.85 8.7 " 1.5 2.78 13.1 " 2. 3.70 17.4 " 2.5 4.63 21.8 u 3. 5.55 26.2 " 3.5 6.48 30.6 " 4. 7.40 34.9 " 5. 9.23 43.7 " 6. 11.5 52.5 " 7. 12.58 61.4 " 8. 14 63 70.1 " 9. 15.40 79. 10. 18.18 88.1 " 15. 26.74 133.9 " 60 DISEASES OF THE EYE. by experiment that prisms noted as of 1° produce deflections vary- ing from 9 to 12 millimetres. Doubtless we must aim at absolute accuracy in all kinds of glasses, and for this reason one or other of the above systems will in the future be chosen; yet for the present the notation by angles prevails. In the choice of prisms we cannot yet lay down rules with as much precision as in the case of focalizing glasses, yet they fulfil an important function, as will be explained hereafter. They may be used simply or in combina- tion with convex or concave glasses. The benefit of prisms is found in connection with the functions of the ocular muscles, and the prism dioptry has a relation to the metric angle which will be here- after referred to, CHAPTER VI. ACCOMMODATION AND ITS ERRORS. Presbyopia.—The natural abatement of accommodation which takes place from the gradual hardening of the lens, has been already described. It remains to speak of it clinically. The period of life at which the ability to read ordinary print at the usual distance of fourteen inches becomes fatiguing, varies in emmetropes between forty-five and fifty years. At an earlier age there may be need of assistance in feeble persons or invalids, while in the very robust and especially in those who do not greatly tax their eyes in near work the occurrence of presbyopia may be further deferred. The size of the pupil has a material influence, and to its small- ness some persons owe their immunity from glasses at the usual age. It is also common to find that a very slight myopia has ex- isted in some individuals who ought, but do not, require glasses in near work. In other cases there may be incipient cataract to account for the refusal of glasses, as will be again mentioned. Presbyopia usually comes upon people like their gray hairs, without announcement or anticipation. They first complain that evening work is troublesome, the light seems dim, and if they bring the work closer, or provide better light, the print fails to become dis- tinct. They find it better to hold the book farther away than for- merly; the print seems pale, letters run together; their eyes smart and give pain. Frequently such symptoms are endured for months, and sometimes the reading distance is pushed as far away as the arm can conveniently stretch. On the other hand people who recognize the probable nature of their trouble are sometimes un- willing to have their true age suspected, and they give up reading. It is, indeed, sometimes ungracious to tell a lady that her troubles can be mended by using a pair of spectacles. While presbyopia usually comes on gradually, it sometimes appears very suddenly and also prematurely, as a result of severe nervous prostration. The question is asked whether it is better to defer the use of glasses as long as possible. To this, the answer should be, that as soon as discomfort arises for need of them, they should be adopted. It is seldom that a glass so weak as .5 D is appropriate. The glass which usually is called for is + .75 D, -f- 53" at the beginning. 62 DISEASES OF THE EYE. Practically many persons get on very well until they require +1 D. A certain amount of accommodative power must remain in re- serve to permit continuous and comfortable Avork. This law gov- erns all muscular activity. How much reserve there should be, it is of little use to theorize, because the question is for each individual decided, according to his own needs. The reading distance varies greatly among emmetropes, and lies between ten and twenty inches; hence, much latitude is to be allowed in the number of the glass, and the occupation and requirements of the person are to be the guide. A portrait painter, a violinist, a book-keeper with large ledgers to run over, these and other workers use their eyes at a range which is proper to their calling, and not that which any theory demands. As to the amount of reserve accommodation, it need not be especially considered. The indication is to give the weakest glass which makes work easy at the accustomed distance. If one reads at 12" and cannot easily see Snellen II nearer than 18" the glass required is ■& — -fa = z^s. — ^ — i D. In metric measure it is 3D — 2D = ID. The rate at which the strength of the glass should be increased is to be considered. About this the rule is not abso- lute. One must be guided by symptoms, usually no addition is needed for two years after first taking glasses; the interval may be longer. The increase should not be by greater increments than .75 D. When 3 D is reached, this glass can usually be maintained for several years. There will be need sometimes of a stronger glass by night than is used by day. In case one wears -f- 3 D for read- ing and finds suddenly a notable failure in reading power and must resort to a decidedly stronger glass, there is serious reason for a careful examination; this may indicate the onset of glaucoma sim- plex. In fact, rapid loss of accommodative power at middle life, whether a glass be employed or not, is a symptom to be regarded with suspicion. It is an accompaniment sometimes of diabetes. When glasses equal to + 4 D and higher, are used, there is a de- cided restraint in the range of accommodation. The working point is at a nearly fixed and unchangeable distance. Hence it is undesirable to advance to the strong numbers. This limitation is inherent in the working of the glasses. It follows of course that with the loss of A and the maintenance by glasses of the working distance at a given point, that the convergence is kept up at a uniform quantity notwithstanding the abatement of ac- commodation. Hence some of the annoyances of using reading glasses are connected with the disassociation between convergence and accommodation. Usually the function of convergence adapts itself to the state of A and no special arrangements are required. But where strong glasses are used, their prismatic effect must be remembered. If the visual axes pass through their inner ed°-e, ACCOMMODATION AND ITS ERRORS. 63 they increase the adduction, while if the glasses are decentred in- ward and the axes pass through their outer half, they act as ab- ductive prisms. The choice between spectacle frames and eye glasses is to be decided chiefly by considerations of convenience, and it is always desirable to give the glasses area enough to keep the frames practically out of the field. Second Sight.—It happens sometimes that at or above sixty years of age, persons lay aside reading glasses and rejoice to find themselves restored again to what they call their youthful sight. This occurrence is not very rare and is popularly called second sight. I have examined many of these persons and found the explanation in sclerosis of the lens with or without opacities, and a small pupil. It has been clearly shown that the refractive index of the lens is in many cases increased and a real myopia may be induced. I can quote such instances, and many authors have written upon it, e. g. Mauthner,1 Priestley Smith,2 etc. It does not always follow in these cases that cataract will develop to maturity and one need not therefore mar the happiness of the person by dismal prognos- tications. While emmetropic persons must in the usual course of nature seek the aid of convex glasses at a certain age, the same necessity befalls l^peropes at a period earlier in proportion to the degree of their error. They have already called largely upon their accommodation, and while they enjoy more of it than others possess, their capacity is sooner exhausted. Hence resort to read- ing glasses at an early age is presumption of hyperopia. On the other hand myopes will weaken the glasses which they have been using. With them accommodation has been little taxed, and if they have been used to working without glasses, it will be found that their working range is always limited. If they have a low grade of error they will be obliged to adopt convex glasses for work and retain concave glasses for the distance. The changes to which they will be subject are easily determined by subtracting from their far-point the number of dioptries required for their near- point. A patient with M = 5 D who would read at 13" or 3 D must use 5 — 3 = 2D. One who has M = 2 D and no longer has A suf- ficient to read at 13" or 3 D must now use + 1 D. Spasm of Accommodation.—The structure of the ciliary mus- cle is in some respects still an unsettled question. Composed of meridional (Briicke's) and circular (Muller's) fibres, the precise course which they assume is not fully determined. Some fibres would appear to be oblique and therefore intermediate in direction between the above sets. It is well known that the relative pro- portion of these fibres differs in eyes of different refractive quality. 1 " Vorlesungen uber die Optischen Fehler der Augen," p. 460. ' Ophthalmic Review. 64 DISEASES OF THE EYE. In H the circular are far more numerous than in M, while in M the meridional exceed the number present in H. Emmert has sought to show that the meridional fibres have an active effect in flattening the lens, which would carry the focus farther back, but such an assertion lacks proof and is contrary to the natural presumption. Myopic eyes accommodate feebly, but on becoming habituated to glasses in early life they soon acquire a normal range. Whether ir such cases there would be found a proportionate increase in circular fibres would be worth investigation. In myopic eyes there is always a certain tone of accommodation which is removed by atropia, but in hypermetropic eyes the proportion of permanent contraction of the ciliary muscle is much higher. This amount of effort is what may be called the tonic state of the muscle. It is impracticable to measure its normal limits. On the other hand an undue degree of constant effort is called spasm of accommodation. For example, if a slight hypermetropia is changed into a myopia of 3 D, or should a hypermetrope of 6 D refuse to accept a glass stronger than 1.5 D. Such are extreme cases and we are called upon to take account of them and of lesser grades whenever they are associated with pain or asthenopia. The causes of spasm are local, viz., such as lie in the structure of the eye, in the condition of the motor muscles, in injuries and in external inflammations such as conjunctivitis, keratitis, episcleritis, etc. These are reflex causes of spasm. There are also less fre- quent cases of spasm due to irritation of the central nervous system, as in epilepsy and hysteria and it may even be associated with hemiplegia; irritation of the sympathetic in the neck and of the cilio-spinal region of the cord have also been assigned as causes. It has been found that one eye alone has been affected, but this is altogether contrary to the rule. An injured eye may set up sympathetic irritation in its fellow of which a component symptom will be spasm of accommodation. All the above-men- tioned causes are exceptional and rare, while refractive and mus- cular errors are by far the common and ordinary causes. That central nervous lesions and various reflex causes have such an effect is indubitable. We are authorized to infer it from the frequency with which the pupil is affected by remote nervous causes. Both the ciliary muscle and the sphincter pupillee are under control of the third nerve and at independent centres. The sympathetic presides over the dilatation of the pupil, and it is claimed by Emmert that it has the same control over the meridi- onal fibres of the ciliary muscle. This is, however, not proven. We may have spasm of the ciliary muscle without contraction of the pupil; and it is recognized that while the nucleus of the third nerve on the anterior part of the floor of the fourth ventricle looks like a single mass, it is functionally divisible into several centres the ACCOMMODATION AND ITS ERRORS. 65 centres for the pupil and for the ciliary muscle being in its front yet separate (see page 153). The diagnosis of spasm rests upon the refraction of the eye when tested by glasses for distance, compared with the refraction proved to exist when examined objectively by the ophthalmoscope, and with the status under the influence of mydriatics. Moreover, if a patient has the habit of reading at a distance too near in propor- tion to the state of refraction, this indicates spasm. Let a patient read with convex glasses, say 3 D. He should see Snellen II from 13" to 6" if his accommodation be fa, or to 4" if it be £. If now he can read only at 8" and brings the book to 3", the difference be- tween fa and £ shows the amount of A which he cannot relax, i.e. ^j. This examination is not to be accounted of more significance than it deserves, because it must be estimated in connection with other symptoms, and the function of convergence has a special in- fluence which must not be overlooked. For this reason it is my habit not to use simple convex lenses in this mode of testing, but lenses combined with abductive prisms. To these reference will be made in speaking of asthenopia. The condition occurs chiefly among asthenic subjects, and more especially among young persons and students. Examination by the ophthalmoscope sometimes shows that even under its illumination, spasm is not relaxed; this may be evidenced by variations in distinctness of the fundus under the observer's eye, or it may entirely elude detection until developed by protracted use of atropia. Treatment.—In cases of muscular or refractive error the appro- priate glasses will be all that is required. In what may be called idiopathic cases, abstinence from use and the employment of my- driatics will usually control the trouble. But in some severe cases the artificial leech to the temples and injections of strychnine (Nagel) have been required. The vigor with which atropia is to be used varies considerably. In some and especially in young sub- jects, it will have to be pushed to the verge of intoxication; of which the symptoms are always unpleasant and may be dangerous. It is better to keep up the remedy for one or two weeks in moderate doses than to resort to the strong solutions. The most frequent remedy is sulphate of atropia, and for young subjects 2 grains to the ounce is sufficient, or at the most 4 grains to the ounce, used thrice daily, 2 drops in the eye. The dilation of the pupil which also occurs may compel the use of colored glasses. Other substances may be employed in case atropia is inefficient or has unpleasant effects. Such are duboisine sulphate and salicylate and still more recent is hyoscyamine and its isomeric form hyoscine. These alka- loids, while more potent than atropia, are also liable to cause toxic 66 DISEASES OF THE EYE. constitutional effects and must be resorted to with caution. Duboi- sine may be used in \$ doses, i.e., gr. ij. ad § i., one drop at a time until its tolerance is proved. It also may happen that the spasm will recur either because the local causes return or because of constitutional conditions. In the obstinate or recurring cases strychnia as a tonic may be used either by the stomach or hypodermically, while special pains must be taken to discover any co-operative cause in weakness of the muscles or in error of refraction, such as hypermetropia or astig- matism. If there be general debility and an asthenic condition, special care must be taken as to food, sleep, exercise, absence of excitement, abstinence in reading and close work. An extremely frequent cause of spasm is insufficiency of the recti externi muscles, a condition whose occurrence is far more prevalent than has been recognized. To this attention will be called and the remedy will be found either in the use of prisms or in tenotomy of the interni (see note, p. 68). Paralysis and Paresis of Accommodation.—A merely feeble ac- commodation and incapability of endurance, is not what is now referred to. We speak of a real abatement of degree irrespective of age. The causes of these conditions may be local, but are gener- ally found in some constitutional disorder or in some lesion of the oculo-motor nerve, either along its track or at its origin, or of the nerves from the ciliary ganglion. We do not take into account the cases of total paralysis of the third nerve which will necessarily include the accommodation. It is not even necessary that the pupil should be implicated. The most frequent cause is diphtheria, and the effect may follow soon after or during convalescence, or at some remote period. It may disappear and recur. It may be the chief symptom of persistence of the poison or it may be only one of many other paralyses. It is asserted by Mooren and Hutchin- son that other affections of the throat not diphtheritic, can cause paralysis of accommodation. After fevers, typhoid and recurrent, after articular rheumatism, in diabetes, in trichinosis, in cerebro- spinal sclerosis, in locomotor ataxia, in essential anaemia, from de- bilitating excesses as by masturbation or venereal indulgence, or alcoholism; as an incident in uterine disease and especially as the result of syphilitic affections we may have impairment or paraly- sis of the ciliary muscle. If the affection is one-sided, the cause will be local and we search for it anywhere along the third nerve to its origin, and the probability will be in favor of syphilis. In- juries of the bones of the orbit or of the eye have an effect probably through reflex influence, and the same has been noted in neuralgia of the dental and other branches of the fifth nerve. Out of this long catalogue of ailments, which is still incomplete, one may well find it ACCOMMODATION AND ITS ERRORS. 67 sometimes difficult to select the correct etiology. Diagnosis need not be dwelt upon; the affection publishes itself by the same tokens that we are familiar with in presbyopia by their more complete manifestation. Prognosis is important because the local malady may be the forerunner of a more serious disease which will com- promise the life or general welfare of the patient. Such will be the cases in which diabetes or an obscure syphilitic disease of the ter- tiary type, or disseminated sclerosis, or locomotor ataxy, sometimes general paresis and occasionally insanity, are looming up, or have already descended upon their victim. For this reason a careful search must be made in the whole domain of pathological clinical research in case some obvious cause is not discovered. (See Gowers.) The history of the patient will be thoroughly sifted. In the greater number of cases happily the prognosis is good, as, for instance, in diphtheria and after fevers, whether typhoid or recurrent. Treatment is, of course, both constitutional and local. The con- stitutional must be decided on general principles of therapeutics as connected with causation. It is to be stated with emphasis that all convalescents must be strenuously cautioned against overtaxing their eyes at the peril of serious paretic and asthenopic trouble of the ciliary muscle. To amuse themselves by reading or sewing to pass the weary hours, is considered a harmless thing, but it too often proves serious in its effects. Women after confinement, or with chronic uterine trouble, patients getting well of scarlet fever, or from severe internal inflammations, need special warning on this matter. If the patient is going about, as strength improves the eye power will improve. The above remark applies to abated capacity for employment of accommodation. When we have to deal with a real paralysis or paresis the great local remedy is sulphate of eserine. It must not be given in concentrated doses, but a solution one-half or one-eighth of a grain to the ounce dropped into the eye once daily, is enough. The pupil will contract slightly and the accommodation will soon be stimulated to action; the near-point is not to be forced to undue proximity and the in- fluence will last for several hours and then gradually decline. Pilocarpine is less energetic and if eserine be unpleasant in its effects on the conjunctiva, muriate of pilocarpine gr. iv. ad 3 i. may be instilled once or twice daily. The constant galvanic cur- rent may be employed with eight to twelve cells, the positive pole over the superior cervical ganglion of the sympathetic at the upper part of the sterno-mastoid, with the negative pole over the closed lids. The current to be kept up for two or three minutes and not to be interrupted. The real value of the galvanization is difficult to estimate, while the influence of myotics is undoubted. It is important, however, to use them in moderation, because they 68 DISEASES OF THE EYE. merely stimulate the muscular fibres and do not act on the cause. We wish to improve their nutrition and not exhaust them. It is also permissible to assist persons in this condition by suita- ble convex glasses for work or reading. If, as sometimes happens, they are sensitive to light, a little tint of blue may be added. It is needless to give any rules for prescribing the glasses. It is, how- ever, proper to guard the patient against presuming upon the value of the help thus afforded him, and venturing to use his eyes as if they were not really crippled. Moderate and not reckless use is all that can be permitted. Note.—In discussing spasm of accommodation that condition has been chiefly in view which is to a great degree unconnected with errors of refrac- tion and motility. When such errors are the cause of spasm, it is not always needful to direct a prolonged treatment by mydriatics. The hydrobro- mate of homatropine, gr. xx. ad 3 i., dropped into the eye every ten minutes for six or eight times in succession will effect relaxation and permit the prescription of a suitable glass. As the solution of this strength is irritat- ing, a 4% solution of cocaine may be employed previous to its use. It usually excites considerable hyperaemia. Its effects disappear within twenty-four or thirty-six hours. Some oculists rely much on this method. I seldom resort to it because the ophthalmometer, the ophthalmoscope provided, if astigma- tism has been found, with the needful cylinder in the clip, and a little patience with trial glasses will master the large number of cases. When obstinate spasm of accommodation confronts me I employ atrophia and with vigor, making a small allowance for the so-called tonic accommodation, about 0.5 D. We have no remedy which will act on the ciliary muscle without acting on the iris and vice versa. CHAPTER Til. ERRORS OF REFRACTION. The e3Te so constructed that rays from a distant object form a perfectly distinct image on the retina is refractively normal and is called emmetropic (E). The eye which does not collect parallel rays to a focus on the retina is ametropic. Ametropia may result from shortening or lengthening of the visual axis, from defect or excess in refractive power, or from want of regularity in the curves or the substance of the refractive media. Various combinations may occur, as will be seen. Among them we have the conditions known as hy- permetropia, myopia and astig- matism as subdivisions of ametro- pia. In hypermetropia (hyperopia, H) the image from a distant object falls behind the retina; in myopia (M) it falls in front of the retina; Fig 27 the place of the image in astigmat- ism will require special explanation. If we confine ourselves to ametropia due to alteration of the length of the visual axis, we see it indicated in Fig. 27. A, B and C represent respectively the em- metropic, the hypermetropic and the myopic eyes. In the next figure a simple biconvex lens is substituted for the eye and if E be 70 DISEASES OF THE EYE. its principal focus, H gives hypermetropia and M gives myopia. At E parallel rays are focussed, while at H they have not yet crossed, and at M they are already diverging. With both H and M vision is imperfect, because in each the retina does not receive a picture formed of accurate points of light, but formed of circles of dispersion; hence it is blurred. It is assumed that there is no effort of accommodation. Diagnosis of Refractive Errors.—We ordinarily assume that correct visual acuity precludes refractive error. It does preclude myopia, but it does not preclude a certain degree of hypermetropia, nor of astigmatism. We have already stated (see pp. 22-25), that visual acuity based upon an angle of 5' is merely an average. For fine determinations acuity should be placed as high as §£ instead of f£, making the visual angle 4'. The age of the subject, the degree of light, the whiteness of the paper, etc., must all be considered. In all such examinations objective methods which are indepen- dent of a patient's assertions are to be added to those which are subjective. Examinations by test types and spectacles may be called sub- jective,—examinations by the ophthalmoscope, by JavaPs ophthal- mometer, and b}' the so-called shadow test, and by Thomson's modification of Schemer's experiment are objective. We always test each eye by itself, and for distant vision first. There is often both greater visual acuity and slight change in the glass preferred, when both eyes are used than each eye alone. A stronger convex and a weaker concave will often be accepted when both are corrected. If visual acuity is made perfect by convex glasses, we may be sure there is hyperopia; if it is made perfect by concave glasses and these are higher than —2D, we may justly think there is myopia, although astigmatism in either of the above cases is not excluded. If no spherical glass will give perfect vision, we try cylindric glasses,. and must not only know whether to choose plus or minus, but must also know in what position the axis is to be placed. If, combining spherical and cylindric glasses, we still fail to ob- tain perfect sight, we must look for irregularities in refraction, opacities, and for deficient perceptive power in the retina or optic nerve. The chief obstacle to a correct result by subjective examination is the patient's accommodation. This may be set aside by atropia, but in practice one will resort to it only when its use is clearly in- dicated ; as for example, when there is severe pain, when contradic- tory results are obtained after patient trial, when subjective and objective methods give opposite findings, when one sees by the oph- thalmoscope that spasm of accommodation exists. With children we resort to atropia more often than with adults. The more we ERRORS OF REFRACTION. 71 can rely on objective methods the better, and increasing skill will indispose one to subject patients to the inconveniences of prolonged mydriasis by atropia. Some advocate homatropia, gr. xx. ad 11. as a sufficient substitute for atropia and preferable because the effect is less prolonged. In this practice I have little experience (see p. 68). To dilate the pupil, cocaine is better than homatropine, while to paralyze accommodation where there is reason for doing it, we have no substitute for atropia. Duboisia may be left out of view in this statement, because it is even more potent than atropia. After a preliminary effort with the test types and spectacle box we take the ophthalmoscope. The indirect method may give in- formation as to the refraction, by using the instrument which Schmidt-Rimpler has suggested, but it is not the most natural and requires special apparatus. We rely on the direct method and while some claim higher accuracy, it is usually easy to come within 1 D of the true state of the refraction. Illumination from a distance of twelve to twenty inches will discover high degrees of error in the display of such retinal vessels as may lie across the pupil. They appear with a hyperopic eye in a virtual image, and as the observer moves his head they go in the same sense. With a myopic eye they appear in a real and inverted image, and as the observer moves, they travel in the contrary sense. Coming as close as possible, the observer with both eyes open to aid in perfect re- laxation of his own accommodation, must also know and allow for any errors in his own refraction. Decided myopia on the part of the observer is a disadvantage, because the lens required for correcting a patient's myopia, added to that which the observer uses, will sometimes be so strong as to make inspection extremely unsatisfactory. As between observer and patient, errors of a like kind must be added to each other, errors of an opposite kind are to be subtracted from each other. An observer with myopia 3 D ex- amining a patient with M 5 D will need — 8 D. If the patient have hyperopia 5 D, the same observer will see with -f- 2 D. If the pa- tient have hyperopia 3 D the supposed myopic observer will see without any glass. On the other hand the hyperopic observer will add the glass to correct his error to that of the hyperopic patient, and will subtract it from that of the myopic. An astigmatic ob- server should have his correction placed upon his ophthalmoscope. Some modification of the above statements will presently be made. What is to be taken as evidence of a proper correction ? Usu- ally the very fine vessels are so regarded, but besides them one should have a clear sight of the granular look which belongs to the pigment epithelium in the region of the macula. If no glass can give this effect, suspect astigmatism, or haziness of the media. The former will have to be ascertained, and a cylinder placed behind the mirror should clear the fundus. If it does not, the media are hazy, 72 DISEASES OF THE EYE. and this will be proved by a strong convex lens, say 15 D, with feeble light and viewing the eye from a point two to four inches away. We first bring the optic nerve to view and turn on the strongest convex or weakest concave glass which will clearly display the fun- dus. In doing this, it is a decided advantage not to be obliged to remove the instrument as one makes changes in the glasses. A hyperopic patient may betray efforts of accommodation, in the vari- ation of the clearness which a vessel exhibits while viewed by the same glass. This may compel resort to atropia. On the other hand, when inspecting myopia the observer is tempted to use a glass which is too strong and thereby bring into play his own accommo- dation. Finally, after patient trial, the fundus is clearly seen; the glass may be + 4 D. Is this correct for the patient's use supposing the observer to be emmetropic ? It will prove to be too weak by the distance at which the observer holds it in front of the eye and the place at which the patient wTill wear his glass. Suppose the glass is — 8 D. This will be too strong and by the same difference. With weak glasses the difference is unimportant, with stronger glasses, and especially with concave glasses, it must be considered. For in- stance, if the observer's glass is 1| inches from the patient's cornea, and the latter wear spectacles at | inch from his eye, 1 inch must be added to the focal length of the glass. For instance, — 8 D is a glass of 5 inches negative focus; to 5 add 1, making 6. Thus the fraction ^ gives — 6.66 D as the glass required. So if the glass by the ophthalmoscope be — 15 D: reduce this to focal length, viz.: ff =2.66. To this add 1 inch, making 3.66. To find the glass in dioptries ^*#B-=—11 D. The difference becomes large. Hyperopia seldom becomes as high as myopia, even after extraction of cataract. If, however, the glass by the ophthalmoscope be + 5 D, this in focal length is -f- 8. From it subtract 1 inch, making 7 Then 4f = 5.7 D, which will be the proper glass. With hyperopic eyes the illumination is brighter, and the mag- nifying power less than in emmetropia. With myopic eyes the il- lumination is feebler, the magnifying power greater and the field smaller than in emmetropia. Hence with extreme myopia, say of 13 D and higher, examination by the upright image is difficult and not satisfactory. In such cases one may take advantage of the fact that an inverted image of the fundus is formed in front of the eye at its own far-point and may inspect it with a convex glass. For example, if the eye be myopic 13 D there will be an inverted image at about 3 inches in front of the cornea, which may be examined by a plus lens of 6 or 8 inches focus. The field will be small but the image bright, and the degree of myopia can be approximated by measuring the distance between the observer and the patient and subtracting the focal length of the convex glass. ERRORS OF'REFRACTION. 73 The foregoing statements apply to anomalies of refraction cor- rective by spherical glasses. If now we have to do with astigma- tism, we may not only discover the fact ophthalmoscopically, but can, within certain limits, estimate its degree by spherical glasses; it is not practicable to have a series of cylindric glasses attached to the ophthalmoscope. The essential quality of astigmatism is that the degree of refraction in a given meridian is greater or less than in a meridian diametrically opposite; the difference between these meridians is the amount of astigmatism. It follows that we have to discover which are the principal meri- dians of refraction, viz.: the least and the greatest, and each must be studied by itself. Now, in examining the fundus by the direct method, if we find that fine vessels in the horizontal meridian need no glass for distinct perception, while fine vessels in the vertical meridian need a plus glass, we have simple hyperopic astigmatism. If we need a plus glass for any vessels and a stronger glass for other vessels, this betokens compound hyperopic astigmatism. In the same way we recognize simple n^opic and compound myopic astig- matism. The degree is the difference between the two meridians. The rule in examining hyperopic eyes, is to use the strongest con- vex glass which is available, and, in examining myopic eyes, to use the weakest concave glass. Now, in eyes having a decided amount of astigmatism, viz., 2 D, a streaky appearance is produced, and the streaks will run in the axis of the greatest ametropia; of course the least ametropia will be at right angles. Moreover, it will be impossible by any spherical glasses to gain a clear view of the fun- dus. So noticeable is this fact that one is incited to examine for haziness of the vitreous, or erroneously led to think that the retina is infiltrated with inflammatory effusion. Such an error is obviated by finding that visual acuity by proper correction is satisfactory, and if the proper cylindric glass can be attached to the ophthal- moscope out of the trial-box, obfuscation of the fundus vanishes. I have provided the means of doing this in the ophthalmoscope figured on page 45, and gain the advantages of learning, first, that the deep ocular structures are or are not healthy; and, second, that the find- ing by the trial-glasses is or is not correct. Another feature in astigmatic eyes is that the optic disc is no longer circular; it is elongated in the direction of greatest ametropia, and therefore is oval. The nerve may be misshapen anatomically, presenting a dis- tinct oval, the long axis usually more or less vertical. In such a case the retinal vessels will show no difference of distinctness caused by their various directions. By the inverted image the streakiness of the fundus can well be seen in high degrees of As, but the lines run in directions opposite 74 DISEASES OF THE EYE. to their course when viewed by the upright image. So, too, the oval1 of the optic disc is reversed. But the objective lens must be held from the eye at a certain distance. It has already been said that in the upright image the optic disc is elongated in the direction of the meridian of greatest curvature, because the magnifying power is greater. With the inverted image the elongation corresponds to the weakest meridian. With the emmetropic eye the size and form of the optic disc undergo no change in the inverted image when the objective lens is held nearer to or farther from the eye. With the hyperopic eye, when the objective approaches it the optic disc becomes smaller, and grows larger as the objective recedes. With the myopic eye, when the objective approaches it, the optic disc becomes larger and grows smaller as the objective is held far- ther away. In both H and M the shape of the disc remains round or oval, whatever the distance of the objective. But with astigma- tism the location of the objective changes the size and the shape of the disc. If with the lens near to the eye the disc be vertically oval, the disc becomes circular if the lens be held from the eye a distance equal to its focal length, plus the distance of the anterior focus, viz., half an inch. If it be drawn farther awTay beyond its focal length, the direction of the axis of the oval is reversed. These •phenomena have been elaborately studied by Javal and by Giraud- Teulon, and can be utilized in diagnosis, but the upright image is by far the most available and instructive. The principles now presented have other applications and they may here be stated. Certain important pathological conditions are revealed by the employment of the ophthalmoscope as an optometer. We are en- abled to measure the depth or height of an object by knowing the number and nature of the glass with which we can view it. Such, for instance, is the depth of excavation of the nerve in glaucoma, the height of a tumor, the elevation of a detached retina, the posi- tion of a body floating in the vitreous. For instance, we find the edge of a glaucomatous cup is to be seen with + 24 (+ 1.50 D); its bottom requires — 16 ( — 2.50 D), the depth of the pit is -fa + fa = fa =fa, or 1.50 D + 2.50 D = 4 D. By referring to the table on pages 89 and 90, we find that H fa (or + 1.50 D) means shortening of axis of 0.47 mm., while myopia fa or — 4 D means lengthening of axis of 1.37.. The depth of the cup then equals 0.47 -f 1.37 = 1.84 mm. On the other hand, swelling of the optic nerve in neuritis may permit + 8 for its summit, and the eye be emmetropic A shortening of the vis- ual axis of ^ = 1.50 mm. which measures the amount of swelling. The same principle applies to all other cases above cited, and by it we are able to give precise data in the facts and progress of a ca se. An interesting case was one of myopia of — 7 D (—-i-), which gives ( ERRORS OF REFRACTION 75 elongation of axis of 2.13 mm. In the e}Te there was detached ret- ina, whose conspicuous part or summit was seen by 4- 7 D or + {, which means shortening of axis of 1.76. The true elevation of the retina therefore was 14 D: equivalent to 3.89 mm. In cases of this kind the inverted image has some value; if we move the objective lens from side to side, the parts of the object which are highest and those which are lowest will not move to an equal degree; in other words, their parallax will be unlike, and they will appear to be displaced unequally. The top of a swollen nerve is nearer than its bottom, and the motion of the objective lens causes its image to have less excursion at the top than at its bottom. The same thing, to a less degree, can be exhibited in the direct image Fig. 29. by moving one's head. So too, with a glaucomatous nerve, the vessels on the edge of the disc, as the lens is moved up and down, move in front of and faster than do those at the bottom of the nerve. For explanation, see the diagram (Fig. 29) from Abadie. Let b be the edge of the excavation, and a lie at its bottom, and the images of these points along the axis of the lens will be at B and A respectively; cA is of course shorter than cB. When the lens is moved down, the points A and B are displaced to A' and B' as seen in the figure. They are no longer in the same line, because the surface of the excavation, a, b, presents itself differently ta the lens. The point B' moves faster and farther than the point A', and passes in front of it, because c' A' and c' B' become, as it were, radii of arcs of circles. A special modification of the indirect method has been made. 76 DISEASES OF THE EYE. by Schmidt-Rimplerl for determining the state of refraction. It is not difficult, and is moderately accurate, and the observer is not compelled to relax his accommodation; yet its being a rather cum- bersome apparatus has prevented its general acceptance. Recently Warlomont and Loiseau have constructed another instrument based on the same method. Yet another objective method of ascertaining the state of re- fraction is to be mentioned which was prominently brought for- ward by Cuignet in 1873 and which has gained considerable cur- rency in England, and is growing into use elsewhere. Cuignet called it keratoscopy, under a false idea of what the method really is, and various names have been given to it, viz.: pupiloscopy, retinoscopy, skiascopy, etc. The most common name and in a certain way suita- ble, although not truly correct, is the Shadow Test.—When the eye is illuminated by the ophthalmo- scope, only a small part of the fundus is covered by the light, while all the rest is obscure. If the mirror is turned at various angles the illuminated surface correspondingly shifts and we may see in the pupil a portion both of the luminous and of the non-luminous surface. The latter is spoken of as a shadow, which is physically incorrect, but is a term convenient for use. Its formation is illus- trated by casting upon a screen the image of a gas flame by a 2- inch convex lens. The image is bright, but there surrounds it a dark circle which has nearly the diameter of the lens. This non- luminous or dark circle corresponds to the " shadow" in the test we are considering. The lens has deflected the rays to form the image and the surrounding space is in darkness. If now in illumi- nating the eye we turn the mirror in oblique positions, the shadow appearing in the pupil will have certain peculiarities which depend upon the quality of the mirror and upon the refractive state of the ■eye. The mirror may be plane or concave. Because of its greater sim- plicity we will assume the mirror to be plane. The observer sits in front of the patient at three or four feet (say one metre) distance, the light will most conveniently be above his head, and the pupil must be moderately large; a mydriatic is frequently required. If the mirror is rotated upon a vertical axis, the shadow moves transversely across the pupil presenting a vertical edge and tests the refractive quality of the transverse meridian. With emmetropia, hyperopia and slight myopia the shadow moves in the same sense as the mir- ror, or " with" the mirror. With myopia higher than 1 D the movement of the shadow is opposite to the expected effect or is " against the mirror." To understand the phenomena see Fig. 29, 1 " Augenheilkunde und Ophthalmoskopie," Braunschweig, 1884. ERRORS OF REFRACTION. from Nettleship. Let L be the light and M the plane mirror. The virtual source of light is an erect image of the flame situated as far behind the mirror as the flame is in front of it, viz.: four to six feet. An image of the flame is formed upon the retina at I. If the mirror be turned to the position of M' the retinal image shifts to I', and the shadow will appear from the left hand side as the move- ment of the mirror would suggest, and coincide with its motion, providing the eye is either emmetropic or hyperopic. If, however, the eye is myopic (see 2 in Fig. 30), the image of the flame is formed in front of the retina and the rays cross; and emerging from the eye they form a real and inverted image between the eye and the mirror which moves in a sense opposite to the rotation of Fig. 30. the mirror because the rays now cross before reaching the observer; the shadow is therefore against the mirror. If the myopia be so feeble that the inverted image of the luminous area of the retina falls beyond the mirror, the shadow will move with the mirror. The retinal vessels will appear, but are disregarded. Suppose we use a concave mirror of 7 or 8 inches or 20 centi- metres focus (see Fig. 31, from Nettleship). The virtual source of light is the inverted image of the flame L found at I, and a second image again inverted is formed at I' in the eye. This image will be distinct and bright if the far-point of the eye is at I, but other- wise it will be out of focus and the luminous area will be less bright. We will suppose the eye to be myopic (No. 2, Fig. 31). It forms a ■78 DISEASES OF 1HE EYE. real image of the illuminated surface V at F. If the^ mirror be turned, I' will move to I'2 and the image will shift to I"2. That is, the image seen by the observer moves in the same direction with ithe mirror. If the eye be hypermetropic or emmetropic, the rays coming iXl 3 I 3C--4 Y\"3C :-i: Fig. 81. .^~~T* from the eye being divergent or parallel will not be brought to a focus, and the observer will see a virtual erect image at I" (No. 3) the virtual focus of V and see its movements as they actually occur, i.e., in the same direction as the movements of the real image I' or I'2 and therefore " against" the movements of the mirror. If the ERRORS OF REFRACTION. 79 myopia be of low degree, viz.: about 1 D, the rays emerging from the pupil are focussed at about one metre and if the observer intercept them before they meet (No. 4) he will refer them to I" and I"2 and obtain an erect virtual image of I' the movements of which will be the same as in H or E (No. 3), viz.: against the mirror. To sum up: with a plane mirror the shadow in emmetropia, hyperopia and low myopia will move icith the mirror. In myopia greater than 1 D, the shadow moves against the mirror. With a concave mirror the shadow in emmetropia, hyperopia and low myopia moves against the mirror. In myopia greater than 1 D it moves with the mirror. In practical work a spectacle frame is put on the patient or a disc bearing glasses is rotated in front of the patient's eye (Brailey) and various glasses are tried until one is found which just reverses the movement of the shadow, or which causes the shadow and the illumination to behave as in emmetropia. This lens is very nearly the desired glass. In hypermetropia we must subtract about 1 D from the lowest plus lens which reverses the shadow; and in myo- pia 1 D must be added to the lowest minus lens which reverses the shadow, because the reversal of movement will not occur until a slight excess in the strength of the glass has been produced. The higher the ametropia, the less luminous will be the pupil, and the less distinct the shadow. We ma}' give attention to some other points besides the direction in which the image or the shadow moves, viz.: to its brightness, to its rate of movement and to the form, straight or crescentic, of its border. If the eye be emmetro- pic, or nearly so, the image will be most correctly focussed and hence at its brightest, whereas, if notably out of focus the rays are more dispersed. For the same reason the border of the image will in emmetropia be best defined and straighter because the flame has nearly vertical borders—if out of focus the image has a more rounded and blurry outline. The movement of the image is most rapid in emmetropia. The detection of astigmatism becomes easy by varying the movement of the mirror about different axes—vertical, horizontal or oblique. If, for example, the reversal of the movement of the shadow is secured when the movement is transversely across the pupil and ametropia still remains in the opposite meridian when the mirror is moved in that direction, another lens must be found which will correct the latter error. Of course the difference be- tween the two lenses thus found is the degree of astigmatism. Both the kind and degree of astigmatism are thus made known. Irregular refraction or opacities in the cornea and lens will also be brought to view. Nettleship says: "for the quick discovery 80 DISEASES OF THE EYE. of very slight astigmatism and of the direction of the chief meridian in astigmatism of all degrees, retinoscopy probably excels all other methods." In his further observations the writer fully concurs: that accu- rate retinoscopy (skiascopy) is not quicker than measurement by the direct ophthalmoscopic method and that in fact the latter is de- cidedly the more rapid if one have a good instrument. " I cannot help thinking," says Mr. N.," that the importance of retinoscopy has been somewhat overrated, and that though in some difficult cases it will remain our best objective test, we shall do well generally to use it as an auxiliary, rather than as a substitute for other methods." The ability to employ the shadow test well is worth possessing, but it can never attain the value of direct ophthalmo- scopic examination of the fundus, because it teaches nothing of the actual condition of the structures. By the methods discussed we are enabled to diagnosticate the kind of refractive error present, and we next have to cor- rect it. WTe resort to trial glasses. We examine at the distance of six metres or as near to that as may be feasible, and endeavor to bring vision up to normal standard by the strongest convex, or weakest concave glasses which will be accepted. Some assist- ance is gained by noting the distance at which the patient can read fine print. If decidedly myopic, he must hold it near, say inside of ten inches, but he will do the same if greatly hyperopic, and also amblyopic, or if astigmatic, or if there be insufficiency of the recti externi muscles. If to read print it must be held very near, and distant sight be very bad, try a concave glass, whose focal length is about the distance at which the book is held from the face; this should greatly improve distant vision if there be myopia, while it will be rejected in most other kinds of refractive error. Should the book in reading be held at a distance beyond fourteen inches there may be hyperopia, but the probabilities are that the fault is princi- pally in the accommodation. Special details in choosing glasses will be given under the special kinds of error to be treated. It must be remarked that special instruments to take the place of the box of trial glasses have been contrived, called optometers. Some are based on the principle of the Galilean telescope, viz.: those of Graefe, of Perrin and Mascart, of Snellen; some have a single convex lens (Burow, Badal, Sous, etc.), and test types are con- tained within the tube of the instrument; some have two convex lenses placed a distance from each other equal to the sum of their principal foci (Hirschberg, Plehn), and in using them the types are hung upside down across the room. In some instruments the focus of the lens coincides with the patient's nodal point as recom- mended by Nagel (Hirschberg, Plehn), the object is to avoid, as ERRORS OF REFRACTION SI much as possible, magnifying the print. Without discussing these apparatus in detail (see article by Plehn1), it may be remarked that they are useful when a large number of examinations must be made rapidly, as among recruits in military service, but they are apt to provoke efforts of accommodation and they do not serve for read- ing. There is also an instrument based on wholly different princi- ples, called the prismoptometer, to which the same objections apply. Still another mode of testing vision subjectively is based upon the experiment of Scheiner, viz.: looking through two small holes about three or four millimetres apart in an opaque disc The effect of this contrivance is seen in Fig. 32. If the emmetropic eye E be focussed for the object O, it will form a sharp image, notwith- standing the splitting of the beam of light into two small pencils, because each will fall upon the fovea. For the hyperopic eye H Fig. 32. whose retina is nearer the nodal point, the small pencils will each make a separate confused image upon it. The same will be true of the myopic eye whose retina is too far from the nodal point, viz.: that each pencil will make its own circle of dispersion. Both the hyperopic eye and the myopic will therefore see the object doubled: it being supposed that the hyperopic makes no effort of accommodation. This device was employed by Porterfield many years ago, but has lately been made practical by Dr. Thom- son, as follows: If across the upper hole of the screen a red glass be placed, and the object be at twenty feet and be a very small gas flame, or a small dot of light, then ametropic eyes will not only see two lights, but one will be red and the other white. For the hyperopic eye it will be seen by the dotted lines going through the nodal point k (see Fig. 32), that the projection of the spot which is uppermost on the retina is below the axis, and if the red glass be on the upper hole of the screen that image is red. It therefore follows that wiien the red image appears to the side of the axis opposite to the side where the red glass is placed, this diagnosticates hyperopia. On the other hand, if the red image be on the same side of the axis with the glass, this declares myopia. 1 Archives of Opth., xvii., 1, 74, 1888. 82 DISEASES OF THE EYE. It is further evident that the greater the ametropia the wider apart will be the two images. It follows that the kind of diplopia and the interval between the images give both the kind and ap- proximately the power of the correcting glass. To make the esti- mate of the power of the glass fairly accurate. Dr. Thomson has so arranged two small gas flames upon a measured bar that each being doubled, one is moved from the other until instead of four flames, three only are seen by the coincidence of two. This dis- tance is read off upon the rod, which is divided into centimetres, and the refraction is deduced. Still more simply the refraction is given by putting in front of the screen the convex or concave glass which causes the images to approach until they coalesce. The objection to this is that myopics will be likely to use accommoda- tion and get glasses too strong and hyperopics to get glasses too weak. Dr. Thomson's use of two flames obviates this liability.1 This method is of value in some difficult cases of refraction where the media are irregular in curve, viz., in conical cornea, or are opaque. With dilated pupil it is easy to apply. It is always most effective with a large pupil, when the holes may be four millimetres asunder and can be used in a dark room and for illiterate persons. The theory of this method and the mathematical formulas are given by Nagel, G. and S., VI. p. 412. For the general theory of optometers, see Nagel, 1. c, p. 315 et seq. We now take up special refractive errors in detail. Hypermetropia. Hyperopia—H.—Hypermetropia is the condition in which, with suspended accommodation, a person requires a convex glass to get his best acuity of sight for distance. It is essential to put aside the accommodation, because up to a certain age and for small de- grees it overcomes and conceals the hyperopia. But it is not to be expected that all cases of high degrees of H will with glasses gain V— 2JL v — 20 • Many who need + 10 (4 D) or stronger glasses, have V= f# or |-8-. In fact, the greater number of strongly hyperopic persons do not have normal acuity of sight. It is the optical result of a shortened visual axis or of want of the crystalline. It also appears in later life, after sixty, by flatten- ing of the crystalline, being the outcome of advancing presbyopia. Flattening of the cornea may also cause it through distention of the globe, as ensues in glaucoma. The usual cause is shortening of 1 See Trans. Am. Opth. Soc, 1870, p. 93, and 1873, p. 83. ERRORS OF REFRACTION. 83 the visual axis. It is a congenital condition. At birth it is almost universal, viz., in 92.4$; up to the fifth year we find 84$; among children in elementary schools 76$; among pupils in higher schools 56$. The degree of H at the second year of life averaged in 300 cases 2 D. For a summary of all recorded investigations of re- fraction by different observers, amounting to 22,743 cases see Randall, Bericht Int. Ophth. Congress, Heidelberg, 1888, p. 511; also Am. Journal Medical Sciences, July, 1885. Anatomical Characteristics.—In his classical treatise which is the foundation of the knowledge of the present day on this subject, Donders portrays many features which characterize the physiog- nomy of hyperopics. That they often have narrow faces and shal- low orbits and eyes deep set, is true, but no conclusive deductions can be drawn from such appearances. It is evident that the axis of the eye increases in higher ratio during the early years of growth than do the optical parts. Hyperopia necessitates an effort of accommodation proportion- ate to its degree, and the result is, that if great, the ciliary muscle becomes enlarged and in adults its size and contour have a well- marked and conspicuous character. This has been exhibited by Ivvanoff. If hyperopia is less than 3 D or 4 D vision generally is normal, if higher it is rarely normal. The explanation is found probably in the wrant of development of the retina and optic nerve. The supposition that the same number of rods and cones as in emmetropia are condensed into a smaller space is inherently im- probable. Donders pointed out that the macula lutea is farther to the temporal side than in emmetropia, and Landolt and Dobrowlsky proved that the distance between the papilla and the macula is greater than in normal eyes. The cornea is more decidedly decen- tered than in emmetropia and the angles gamma and alpha are usually very large. With the higher degrees of H the eyeball is evidently small and proclaims its imperfect development not only in this fact, but even in imperfect vigor of the ciliary muscle and of the motor muscles. The optic nerve in marked degrees of H often shows indistinctness of tissue, it may be deep red or grayish, its edges are often striated and ill defined, especially on the nasal side. It may be, and in high degrees it usually is, intensely red, and because of such signs some have regarded the condition in- flammatory. This, however, can hardly be sustained by clinical experience. What is known as the choroidal crescent, viz.: the interval between the edge of the choroidal and the scleral open- ings is not infrequently observed, and it is usually on the temporal side. Sometimes the nerve is anatomically oval, while the oval shape due to astigmatism is also frequent. Even the retina in the neighborhood of the nerve sometimes is hazy and seems thick. 84 DISEASES OF THE EYE. While these appearances belong to higher degrees of H, we shall find in all hyperopic persons having symptoms of asthenopia, that the nerve is red, perhaps very deeply, and the veins are large—in- dicating reflex irritation of the papillary circulation. Symptoms.—In using their eyes, hyperopes of moderate degree, or rather such as have adequate accommodation and good muscles, exhibit no difference ordinarily from emmetropes. If examined by glasses they may not accept them. In such persons the whole error is latent. On the other hand, they may see equally well at six metres with and without a given glass. The glass which they accept rep- resents the " manifest H." Under atropine such a person would show a higher degree and accept a stronger glass; the repressed amount is the " latent H." The " total H " is of course the sum of the manifest and the latent. It is also possible that a hyperope requires a weak glass to give him the best vision and will also see equally well with a stronger one. Suppose he needs + 1.5 D for vision f and will accept + 3 D. It is evident that his manifest H =3 D. Of this he is able to correct 1.5 D voluntarily, and this part of the " manifest H " Donders calls " facultative." The total H can be usually seen by the ophthalmoscope, and can be elicited by using atropine in full dose. But my own experience agrees with Schweigger's ("Handbuch der Augenheilkunde," p. 49, 1880) that exceptional cases occur which do not yield up their total H to the ophthalmoscope. See also article by Weiss (Graefe's Archiv fur Ophthal., XXIV. ii., 90), one by Agnew (Trans. Am. Oph. Soc). I observed one such person, a lady aged 32, for three months and could not make out an error which finally under atropia proved to be 2.5 D. Persons with high degrees of H, especially if they be no- tably amblyopic, will bring print and work very close. They will behave as if near-sighted. They will seek a strong light, will see badly in the evening. They often have small pupils. They apply for relief either because distant vision is indistinct, or when they have symptoms of asthenopia. Distant vision fails when the ac- commodation can no longer correct the error. It is evident that with parallel axes, the hypertrope has been accustomed to exert an undue degree of accommodation. As this faculty declines with years, he finds himself obliged at an early age to seek the aid of convex glasses, and he also is apt to find that a weak convex glass improves and restores to him his former acute distant sight. This is what usually transpires with moderate H in healthy and vigorous persons. An attack of sickness, especially of diphtheria, chronic ill health, notably uterine diseases, and extreme taxation of sight, may cause the same results before the usual decline of accom- modation would develop them. Bnt it is more common under the influence of such causes for the subject to suffer, not from defective ERRORS OF REFRACTION. 85 sight either for near or far, but from pain in close eye-work. This is called accommodative asthenopia. The symptoms are that after working for a certain period the person must stop because the sight is blurred, there is pain in and about the eyes and some- times remote reflex symptoms, such as headache, pain down the spine, sickness of stomach, etc., etc. The ability to resume work after rest, to work better under stimulus, that the periods of ability to work grow shorter:—these are characteristics of this condition. Many more touches might be given to this picture, but they would serve no good purpose. It may, however, be added that palpebral irritation, chalazia, styes, blepharitis marginalis, and hyperaemia of the palpebral conjunctiva are frequently seen. The inflammations of the border of the lid occur most often in young subjects and fre- quently without any complaint of distressful sight. This is a well established fact and was noted by Roosa and Schirmer and has long been familiar to the writer. Palpebral conjunctivitis is almost always present when asthenopic symptoms exist, and explains the sensations of smarting, dryness, heat and the inclination to press upon the globe—as well as the comfort gained by applications of lukewarm water and soothing lotions. Hj^permetropia makes its appearance in the order of nature be- yond sixty or seventy years of age, and then dimness of sight for distance, correctible by a weak convex glass, is the symptom ob- served. Usually there is no asthenopia. Another class of cases exhibit the effects of their error in dis- turbances of the muscles; they are either inclined to converging strabismus or it becomes fully established. We have spoken of the intimate relation which in emmetropia subsists between accommodation and convergence. For a given number of dioptries of accommodation, say 4 D, an equal number of metric angles must be brought into use, i.e., 4. With hypermetro- pia the law is not the same. On the contrary, with no convergence the subject must put forth as many dioptries of accommodation as will equal his total error. If hyperopia = 4 D and he accommo- date for 250 mm., he uses 4 + 4D-8D of accommodation for 4 metric angles of convergence. At once a disproportion appears, which may easily be converted into a complete disturbance of binocu- lar vision, if for any cause there be difficulty in distinct vision or in convergence. The two functions are in a state of unstable equilib- rium and are easily disassociated. It has never been shown how large is the proportion of hypermetropes who acquire strabismus, but Donders showed that about two-thirds of the cases of strabismus convergens were hypermetropic. The latitude which exists in the amplitude of convergence for a definite amount of A, and the varia- tion in relative A for given degrees of convergence, explain why so 86 DISEASES OF THE EYE. large a proportion of hyperopic subjects never fall into strabismus* But that they are subject to this tendency is evident. It must also be remarked that other refractive complications are frequent in H, viz.: astigmatism and unequal refraction of the two eyes (anisome- tropia). To this must be added that often there is unequal visual power in the two eyes and inferior visual acuity of one or both forces the adoption of a distance for near work, closer than the degree of H would demand. It is not found that hyperopic persons choose a wTorking point more removed than emmetropes; on the contrary, their inclination is to adopt a closer near-point, until the failure of accommodation brings on premature presbyopia. The occurrence of strabismus is evidently determined by a variety of factors and among the most potent is the actual power of the muscles of adduction and abduction. Efforts of accommodation stimulate the interni and the effect is reciprocal. It is a subject worth investigating on a large scale what is the adduction and ab- duction of hypermetropes who do not squint. (See " Die Aetiologie der Strab. conv. hypermet." von Dr. Richard Ulrich, 1881.) The subject will be referred to again under the head of strabismus. Complications.—It has been said that amblyopia, astigmatism, inequality of the eyes both as to refraction and vision, strabismus, spasm of accommodation and asthenopia may coexist with hyper- opia. It is recognized to be a frequent concomitant of glaucoma and is regarded as predisposing to it, while that it may predispose to idiopathic retinitis (Dobrowlski) is not probable. Diagnosis.—The acceptance of a convex glass for distant vision and that by it vision is not impaired or may be improved, is conclu- sive of hypermetropia. Its non-acceptance does not disprove it. If accommodation is fully paralyzed by atropine non-acceptance of the glass disproves it. With this must be combined objective ex- amination, viz.: by ophthalmoscopy, by Cuignet's method (shadow test), and for decided proof it must be possible to eliminate accom- modation both from the observer and the patient. In most cases the upright ophthalmoscopic image will settle the matter easily, by showing that a convex glass permits clear vision of the fine retinal vessels near the macula, or of the retinal epithelium (the granular look). For H less than 1 D good observers may be in doubt with objective methods, but if needful, atropia will determine the point. Prognosis.—The error is not curable, but is correctible. The degree of vision will not be impaired, but as the accommodative- power becomes exhausted, stronger glasses will be needed, and in higher degrees of H one pair will be required for distance, and a second for the near-point. The endurance of hyperopic eyes usually falls below the normal amount, and as they come to use high glasses- for work, this disability is liable to increase. They often feel the ERRORS OF REFRACTION. 87 necessity of constantly wearing glasses to be a grievous burden, but the prognosis is relatively good. Treatment.—We have no occasion to deal with these persons until some of the above-mentioned subjective symptoms cause them to ask for relief. So long as their accommodation can with- out conscious strain overcome their error, they need no aid. 1st. In the simplest cases the first call for help is when they find near vision indistinct or tiresome, i.e., when A is not large enough to easily overbalance H. We usually meet this in persons from 25 to 40 years of age. They may accept a weak glass for distant vision, but without it may have V = f. It is in reading, etc., that they find the print blur and the light seem bad and the eyes grow tired. We always test each eye separately and cover the other by a screen. The convex glass which makes reading comfortable, whether .75 D,or 1 Dor 1.5 D,is all that they need. This they may use at discretion, and there is no occasion for a distant glass and atropine need not be used in the examination. Let the same person grow older and find distant vision a little hazy, then he may take the convex glass which restores its sharpness and at the same time he will need a stronger working glass and will have to make habit- ual use of it. The glass for distant sight he may use at his plea- sure for looking at pictures or at persons in an audience, etc In time it may come to pass that without a glass, distant sight is un- pleasantl}' obscure and then the person will gladly take refuge in its continuous employment. His occupation may require sharp vision at moderate distances, say at 10 feet, and he may even need a series of three glasses to meet all his requirements. Portrait painters find themselves sometimes in this predicament. It is con- venient for them to have a glass ground with double foci. For- merly such glasses were made in two pieces (Franklin's glasses), now separate foci can be ground upon the same piece of glass. The stronger should be below and it should occupy less area than the upper. At the dividing line prismatic distortion occurs, but generally the person can soon habituate himself to the glasses. They must be larger than the ordinary form. Sometimes a slip of glass is stuck to the lower portion of the weaker one by Canada balsam. 2d. The person complains of asthenopic symptoms, and they may arise either when at work, or be constant. In such cases the error may be small and the distress be due to feeble health, overwork, astigmatism, feeble muscles, etc., or the error may be large, and there may be notable amblyopia. The mode of dealing with such a case will depend upon the age, the general con- dition of health and upon the intensity of the asthenopic symptoms. It is in this class of cases that we are confronted with the question, 88 DISEASES OF THE EYE. Is atropine necessary ? The case is to be looked upon as one of ac- commodative asthenopia, and all the elements which enter into this morbid complex, must be taken into account. A real attempt must be made to correctly estimate all these elements without resorting to atropine. First, one must test distant vision and find the strongest convex spherical glass which will be accepted. If visual acuity remains below the normal, the next inquiry is for as- tigmatism, which will be hereafter discussed. If sufficient success is not attained in bringing up the visual acuity, try the objective examination by direct ophthalmoscopy or by the shadow test, to see what glass, or combination of glasses, is indicated. Let the patient use these for distant vision. He may or may not gain bet- ter or correct acuity. Perhaps he now accepts a stronger glass than at first. This means that accommodative tension is abating. He may not consent to the stronger or the objectively ascertained combination. His answers may be contradictory, he may evidently feel uncertain what he sees, and may say that the type swims, or comes and goes. The glass, objectively ascertained, may be much stronger or be very unlike the glass which he is willing to take. These symptoms betoken accommodative strain. If after a little patience in pressing upon him glasses, which approximate to the de- gree of error objectively ascertained, he accept them and acuity be- comes | or |, let him take these and read with them for half an hour, provided he be a person under 25 years. Usually these glasses, if found satisfactory in reading, will serve the purpose and a mydri- atic need not be employed. Such a proceeding will take considera- ble time and patience, and it is assumed that the examiner has an unlimited supply of the latter. It will be justifiable to give the patient these glasses with the proviso, that he be told that they may possibly not serve, and that if they cause trouble or fail of relief he must come again. In other cases the examination may be repeated the next day and then the patient is likely to be better able to control his eyes and faculties. Glasses selected in this way necessarily leave uncorrected what may be called the normally latent error. The age and health of the subject have a controlling influence over the amount of this fraction, which may be called the physiologically latent error, and it necessarily varies with the degree of H. To young and vigorous subjects whose subjective symptoms are not severe and for whom visual acuity f or f can be obtained, it is proper to prescribe glasses without resort to a mydriatic. Whether the glasses are to be used only in near work or at all times, depends on the degree of error, on the vision without them, and on the amount of discomfort previously existing. If constantly worn they sometimes become thereafter indispensable, or in other cases, they in a little time bring about relief, and may ERRORS OF REFRACTION. 89 be laid aside for distance and used only for the working point (punctum agendi). 3d. But another possibility presents itself: we have not attained satisfactory visual acuity, or the difference between the glasses objectively found, and subjectively approved is too great, and the patient's answers show that his accommodation is under severe strain, or his subjective symptoms are severe. Further evidence of serious spasm of accommodation is found in the variable sharp- ness of the fundus under the ophthalmoscope, as various glasses are employed. Under these conditions a mydriatic must be used. Oftentimes the prolonged mydriasis of sulph. atropia, which will extend to seven or ten days, is a serious inconvenience, at other times it must be regarded as a therapeutic measure, as well as needful for diagnosis. Then sol. sulph. atropia, gr. iv. ad § i., will be dropped into the eyes from three to ten times within one to three days according to the susceptibility of the patient; constitu- tional symptoms are liable to occur, and warning must be given accordingly. With milder subjective symptoms hydrobromate of homatropine, gr. xx. ad § i., may be dropped in, every ten minutes until relaxation occurs, and its effects will pass in twenty-four or thirty-six hours. Sulphate of duboisia is our most active agent, but has no special advantages. Muriate of cocaine 4$ solution has much less effect on accommodation than on the pupil. With suspended accommodation the full amount of hyperopia will be discovered, astigmatism will be sought for, and while with dilated pupil, acuity may not reach the normal, an ophthalmoscopic examination by the upright image with the full correction both by spherical and cylindric glasses will show whether defect of vision is due to a real amblyopia. Further evidence of amblyopia will be had by testing for a small central color scotoma, which is some times found in one eye of hyperopes who have never squinted. If the degree of H be important, fa or greater, it will very fre- quently be advisable to give the glass which fully corrects H. In most cases it will be best to wear it continuously. Under what circumstances should convex glasses be constantly worn ? Some people answer for themselves by finding that they are wholly un- comfortable without them, even though the degree is not strong The comfort of the individual is of necessity the fundamental rea son for constant use, and that only in this way can it be secured, is not always to be anticipated. That such use is likely to be need- ful will be probable of cases of high degrees, viz., fa and more, whether in young or old subjects; the more advanced in age the person, the more likely is he to require constant help. Again, the same advice is to be given to very sensitive persons whose eyes give them much pain. Under this head will come a large class of 90 DISEASES OF THE EYE. semi-invalids and impressible and neuralgic persons. On the other hand, the dull and torpid and unobservant will often be quite in- different to the aid of glasses for distance, even though they have a marked degree of error. Furthermore, something has to be con- ceded to the sense of what is becoming to their personal appearance in persons of both sexes, and, while a physician will not modify his deliberate opinion and advice in deference to what may suit his patient's whim, there are doubtful cases in which his abstract views must be modified by the patient's preference. For persons with marked H there can be no doubt of the advantage gained by constant use of glasses, because the range of accommodation is brought within the physiological limits, and the continued strain on the ciliary muscle is removed. Moreover, it is a frequent obser- vation that in this way acuity of vision decidedly improves in the higher degrees of H. This is not simply the effect of enlargement of retinal images, but of improved health of the retina. If the requisite glass is as high as 4 D it often causes discomfort when first worn, because one's estimate of distances is disturbed and more light is gathered into the pupil. Special care must be taken with the frames that the centres of the glasses coincide with the visual axes. If decentered in either direction a noticeable pris- matic deflection occurs ; this may or may not be desirable. With high degrees of H an increase of power in the glasses required for reading is usually needful at an early age. A serious disadvantage belonging to strong glasses is that they greatly restrict the range within which reading is comfortable. The book must be held at a certain and almost fixed distance. As an instance of extreme hyperopia, I may mention a boy ten 3Tears old who required a glass -§- of an inch focus or 33 D. To find hyperopia of 10 D or 12 D is not excessively rare. On page 83 some remarks were made on the prevalence of H in early life. The results belong to examinations for the total H. Among adults who were largely students and soldiers and after eliminating the statistics whose value appeared to be doubtful Randall finds in 22,743 examinations, Em. 23.8$, M. 21.4$ and H 51.9$. Admitting that more than half the young adults of the com- munity may, as these figures indicate, be hypermetropic, it by no means follows that a large proportion will suffer inconvenience if the error remains uncorrected. The state of health, the vigor of accom- modation, the mode of life, and the exigencies of eye-work must all be taken into account. Donders, in 1864, " Accommodation and Refrac- tion," p. 174, said: " In an absolutely mathematical sense no single eye is perhaps to be called emmetropic." Randall, in 1888, makes the same observation (loc. cit.), and adds: " Approximate emmetropia (Am. < ± 0.5) is infrequent at all ages, probably at no epoch exceed- ing 10$." Happily the human race is not compelled to attain mathe- ERRORS OF REFRACTION. 91 matical perfection, to enjoy a reasonable degree of felicity. It would be as hard to find an individual perfectly healthy in body as to find an absolutely emmetropic eye. A limited departure from a per- fect standard must be admitted to be consistent with a normal eye. The rigid scrutiny which reduces emmetropia to 23.8$ and makes hypermetropia 51.9$ conveys a wrong impression of the relative proportion of what their experience shows to be the number of persons with normal eyes. The definition of such an eye may be stated to be one that has acuity |£ or f| without glasses and that can perform all necessary work without pain or fatigue. It would be a serious error to insist on the possession of a mathematically faultless instrument before we could accept a standard normal eye. In a practical sense small errors of hyperopia or astigmatism whether in the cornea or in the lens must be disregarded. Donders placed these insignificant errors between Tfg- and fa. At the pres- ent time the allowable limit would be somewhat less. But the ten- dency now is toward what seems to me to be a needless degree of exactness. More will be said on this point in the chapter on asthenopia. The examinations of Seggel in the soldiers of the Bavarian army are admitted to be exact and trustworthy, and he reports on 3,052 eyes with the result of E. 46.7$, H. 40.6$, M. 11.4$, and astigmatic and diseased eyes 1.3$. These were young and healthy adults who had not been given to exacting eye-work. Graefe's Archiv, Bd. XXX., 11., p 111, 1884. The degree of shortening of the optic axis which corresponds to a given amount of H is given in the subjoined table from Landolt: Table of Axial Hyperopia. Degree of H. Amount of shortening. Total length-of Axis. Degree of H. Amount of shortening. Total length of Axis. mm. mm. mm. mm. 0 0 22.824 (normal). 8. 2.28 20.54 0.5 0.16 22.67 8.5 2.41 20.41 1. 0.31 22.51 9. 2.53 20.29 1.5 0.47 22.35 9.5 2.66 20.16 2. 0.62 22.20 10. 2.78 20.04 2.5 0.77 22.05 10.5 2.90 19.92 3. 0.92 21.90 11. 3.02 19.80' 3.5 1.06 21.7(5 12. 3.25 19.57 4. 1.21 21.61 13. 3.47 19.35. 4.5 1.35 21.47 14. 3.69 19.13: 5. 1.50 21.32 15. 3.91 18.91 5.5 1.62 21.20 16. 4.11 18.71 6. 1.76 21.06 17. 4.32 18.50 6.5 1.90 20.92 18. 4.52 18.30 7. 2.03 20.80 19. 4.71 18.11 7.5 2.16 20.66 20. 4.90 17.92 It will be seen in the table that the axial shortening for each D; is about 0.3 mm. up to 7 D, but that for higher errors the abate- ment in axis sufficient to cause 1 D becomes less and less. 92 DISEASES OF THE EYE. MYOPIA. M. There are two kinds of myopia. In one the refractive power -of the media is excessive, while the optic axis is of normal length. In the other and common form, undue elongation of the optic axis is the essence of the error. The amount of actual increase in length of axis may in general be stated for the lower degrees, to be about 0.3 mm. for each D. Unlike hyperopia, the increase of axis to make one additional dioptry of myopia becomes larger as myopia increases. Beginning for 1 D at 0.32 mm., between — 5 D and — 10 D the average increment for a single D is 0.41 mm. Be- tween — 10 D and — 15 D the average increment for a single D is 0.51 mm. Between — 15 D and — 20 D the average increment for a single D is 0.60 mm. Exceptionally it has been shown that Table op Axial Myopia. Degree of M. Amount of lengthening. Total length of Axis. Degree of M. Amount of lengthening. Total length of Axis. mm. mm. mm. mm. 0 0 22.824 (normal). 8. 2.93 25.75 0.5 0.16 22.98 8.5 3.14 25.96 1. 0.32 23.14 9. 3.35 26.17 1.5 0.49 23.31 9.5 3.58 26.40 2. 0.66 23.48 10. 3.80 26.62 2.5 0.83 23.65 10.5 4.03 26.85 3. 1.01 23.83 11. 4.26 27.08 3.5 1.19 24.01 12. 4.73 27.55 4. 1.37 24.19 13. 5.23 28.05 4.5 1.55 24.37 14. 5.74 28.58 5. 1.74 24.56 15. 6.28 29.10 5.5 1.93 24.75 16. 6.83 29.65 6. 2.13 24.95 17. 7.41 30.23 6.5 2.32 25.14 18. 8.03 30.85 7. 2.52 25.34 19. 8.65 31.47 7.5 2.73 25.55 20. 9.31 32.13 eyes whose axis comes within the usual limits of 22 to 25 mm. may be myopic. Stilling measured twTo eyes with axes of 26 and 25 mm. respectively, in each of which the myopia had during life been determined to be exactly 5 D. It is not found that the curve of the cornea has any regular relation to miopia. I have found the radius both shorter and longer than normal. As to the refractive. index and curves of the crystalline we know nothing. It has been shown that a few cases of myopia are congenital,1 and often the subjects belong to the poorer classes of society, while the vast majority of cases exhibit the condition after eight years of age. Its beginning may date from the twelfth or fifteenth year of life, or even perhaps later. The period of most rapid development is 1 Tscherning," Studien iiber die Aetiologie der Myopie." Graefe's Archiv xxix., 1, 201. ERRORS OF REFRACTION. 93 between the ages of twelve and eighteen. The proportion of myopes in the community is estimated by Tscherning (Copenhagen) at 8$. Great attention has been given to the production of myopia in chil- dren, and as the result of the labors of many observers we have statistics of over 70,000 cases. We have seen that the normal condition of the eye at birth is hyperopia, and that increase in length of the axis brings about emmetropia, while a further advance will occasion myopia. It is of great importance to discriminate between the moderate degrees of M which are simply an inconvenience with some compensating advantages, and the higher grades which are eminently serious and often dangerous. Donders pronounced every myopic eye a diseased eye. Every highly myopic eye is diseased, but within late years it has been shown that the remark conveys a false meaning respecting a large number, and these the moderately myopic eyes. It will be admitted that up to 3 D the cases are seldom serious, it being generally possible to give perfect vision by proper glasses. Above 6 D we do not expect to procure correct vision, and look for various pathological lesions and often there is great peril to sight. Blindness, as the effect of detachment of the retina, of intra-ocular hemorrhage, etc., is too often the outcome of myopia. The cases between 3 D and 6 D may or may not be of serious character. M3Topic persons whose error is moderate recognize distant ob- jects tolerably well, notwithstanding when tested by the usual methods vision may be less than fa\. Even in this respect great differences will be observed. I have noted with the same optical error uncorrected, say 1 D or 2 D, differences of vision varying between f g- and fa%. Their habit is to half shut the lids, to reduce the pupillary aperture, and the3r rely upon their familiarity with accessory conditions of form, color, brightness, contrast, etc. For work near at hand, reading, sewing, etc., they have the advan- tage of less effort of accommodation and get larger images by a close near-point. At the usual age of presbyopia they are not obliged to use glasses, and there may be an abatement in myopia and improved distant sight. This advantage will not be availa- ble where M is greater than 3 D or 4 D. Causes.—■Occurring ordinarily during school life, it has natu- rally been inferred that unfavorable conditions in the school room as to light, the attitude of the head, the distance of the book or paper, the hygienic conditions, the duration of study have an im- portant bearing on the production of myopia. Cohn, Fuchs, Horner and others have diligently labored to correct in their respective countries the faults to be found in school construction and arrange- ments. There has been room and need for the improvement which 94 DISEASES OF THE EYE. has been brought about. It now appears that under the better conditions of certain modern institutions in Germany, an abate- ment in the number of cases of myopia has been realized, amount- ing to 6$ (von Hippel). This is not a large gain and it may be put alongside the fact established by Dr. H. Derby that a course of study in such an institution as Harvard University in this country, where the hygienic conditions cannot be impugned, results in the development and increase of myopia. The subjects were between the ages of seventeen and twenty-five. Fixing upon objects at short range, say, less than 12 inches, implies strong efforts both of accommodation and convergence. Let the sclera be relatively weak, and the back of the globe begins to stretch. Nor is this re- sult limited to the juvenile stage of life. I have seen it begin in an ap- parently robust student of twenty, during his third year in college. Habitual occupation with small objects near the eye, as when children first take to books, either for pleasure or study, or when learning to draw or to sew, or they are kept at a piano in a dark corner, or the school-room has not the full quota of light which is each child's right, or the benches and desks are so contrived that the child sits crouched or crooked, or a heavy lexicon compels a stooping posture, or the text is badly printed, or is in a language whose characters are intricate and unfamiliar, like Greek, or Ger- man, or Hebrew : such are some of the occasions of myopia. It has been shown that accommodation alone has little effect in causing nryopia, but being associated with convergence the two are considered together. The evils of convergence are manifestly due to excessive pressure. Now strabismus occurs mostly with hypermetropia, and the apparent contradiction is explained by call- ing to mind that the short axis eye will rotate easily, while the long axis eye of myopia presents proportionate difficulty in rotation. Moreover, the most hurtful conditions appear when antagonistic forces oppose each other, which no longer arises when a weak muscle has surrendered, as in strabismus. It is a recognized fact that op- posing muscles aggravate myopia, certainly in causing asthenopia, and probably in contributing to extension of the visual axis. The following are the factors which have been dwelt upon as effective: 1. The internal and external recti cause compression under high angles of convergence, by which the externi are stretched and the insertion of the optic nerve is dragged upon. 2. Stilling1 lays chief importance upon the influence of the superior oblique, which he finds to be extremely variable in its direction and extent, and which, when the visual lines converge, aids in adduction. If, as he sometimes finds, its course is quite transverse and its fibres inserted near the optic entrance, it adds materially to the compres- 1 " TJntersuchungen uber die Entstehung der Kurzsichtigkeit " Wiesba- den, 1887. Seggel, Graefe's Archiv, xxvi., 2, s. 1, 1891. ERRORS OF REFRACTION 95 sive action during convergence, and also drags upon the optic nerve entrance. He adduces autopsies of 102 eyes in support of his theory (p. 32, 1. c.) and also takes into account the shape of the orbit in so far as thereby the pulley is placed higher or lower and permits the muscle to lie more or less closely in contact with the globe. 3. Arlt attributes to the inferior oblique and external rectus an indirect effect by pressure on the venge vorticosae which promotes choroidal stasis. 4. The same congestive tendency results from bending forward of the head and neck. 5. Subacute inflammation of the choroid and sclera, which Graefe designated under the name of sclerotico-choroiditis posterior and by which he explained the choroidal crescent adjacent to the papilla, was formerly much dwelt upon. In this view he was, to a considerable degree, in error, while that in some cases such an inflammatory process occurs, is admitted. It is now accepted that both mechanical and inflammatory or degenerative processes go on simultaneously. In some cases the latter seem to be primary, while the former are by far the most common, and always co-operate with the latter. It is easy to believe that there may in some cases be a lack of resis- tance in the posterior part of the sclera, yet anatomically this is difficult of proof. Clinical experience has shown that suspension of accommodation has very slight influence in abating myopia. Stilling thinks that movement of the eyes up and down in read- ing is an important provoking circumstance, the effect of the obliqui being then greater. He remarks that among watchmakers myopia is rare, while very common among instrumental musicians. Stilling •calls attention to the prevalence of a low-roofed orbit among myopes, and manj7 have entered on this inquiry, which seems to have a basis of fact, although opinions vary. The effect is to make the action of the superior oblique more compressive. But while mechanical action explains the usual cases of mj'opia, it does not explain certain exceptional forms, viz.: the congenital, such as occur among illiterate people, and those who use their eyes only for distance, and the cases where myopia suddenly and rapidly develops in adults or old persons. These are cases of inflammatory action akin to hydrophthalmus, and, as above remarked, many times both causes combine. The effect of constitutional conditions in exciting or predisposing to myopia is forcibly presented by Dr. Batten (Oph. Review, Jan- uary, 1892), and he lays stress on the tokens of general vascular lesion in young persons, as proven by, 1, spontaneous hemorrhages (epistaxis, menorrhagia, retinal hemorrhages); 2, capillary conges- tion ; 3, cardio-vascular disease. He dwells on the full, soft pulse of young persons, an acute rheumatism as a frequent precursor of myopia, and that choroiditis may be both a cause and conse- quence of the lesion. 96 DISEASES OF THE EYE. We have thus an ordinary and an extraordinary type of myo- pia, sometimes called the benign and the malignant, also we are to distinguish between stationary and progressive conditions. Pro- gressive myopia if occurring during the years of growth need not excite very serious concern, but if progress continue beyond the age of twenty or a sudden increase appear during adult life we have before us a grave condition. In making the distinction be- tween these conditions, we must be guided by the degree of visual acuity which is obtainable by glasses, and by the ophthalmoscopic appearances. High degrees of myopia almost never have normal vision, and frequently we find lesions quite sufficient to account for it; even when we do not, stretching of the fibres of the optic nerve will explain it, or in rare cases it may be fair to assume that a con- genital or precedent amblyopia compelling very close approxima- tion of objects, has been the predisposing cause of the actual myo- pia. It becomes proper next to consider the Functional Disturbances and Pathological Anatomy.— The error often becomes established without the consciousness of the subject; it may reach 3 or 4 D and not attract his attention. Fre- quently it is recognized by accident or by the questions of another. To accidentally find myopia in one eye and not in the other is not at all rare. On the other hand, the development may be with pain or weariness and photophobia and inability to study. Besides the indistinctness of distant objects there may be occasional blurrings of print and the eyes look irritable. When of moderate degree the myopic eye looks normal, but in the higher grades it becomes prominent, pushes the upper lid, and in its movements betrays its elongated form. The anterior chamber is deep, the pupil large and slow to act, the periphery of the iris is retracted. The myope has a vacant look and his face has little expression, he half shuts his lids and wrinkles his forehead. He is often abstracted, inattentive to his surroundings, perhaps easily embarrassed, or without mean- ing it has an air of effrontery, is more fond of books than of society, given to sedentary rather than to out-door and active pursuits. To the ophthalmoscope the eye will in moderate cases show no lesion, but in most cases we find a whitish crescent on the outer side of the optic disc. This is called the choroidal crescent and by Jaeger the conus (see Fig. 33). It is found in a few cases of hyperopia and emmetropia, but it is almost distinctive of my- opia. Fig. 33a shows in section the elongation and atrophy of the choroid at the back of the eye. Loring (Trans. Internat. Med. Con- gress, 1876) found in 2,265 eyes that the crescent existed among emmetropics in 3.33$, among hyperopics in 3.49$, among myopics in 20.56$. Schnabel1 among 135 cases having the crescent found 1 Graefe's Archiv fur Oph., xx., 2, p. 1. ERRORS OF REFRACTION. 97 73$ myopic, 13$ hyperopic and 13$ emmetropic. When high de- grees of myopia are examined the crescent becomes still more frequent. Graefe put it at 90$. Much discussion has been held upon the significance and origin of- this lesion. We have at length, thanks to the observation of Nagel * and the anatomical examinations of Weiss2 and Herzog Carl Theodor,3 facts which determine its character and mode of formation. In 1861 Jaeger4 when describing the crescent, spoke of a peculiar look of the disc on the nasal side, and said that such eyes anatomically examined presented a peculiar bending of the optic nerve fibres toward the crescent. These remarks did not excite attention. In 1880 Nagel brought to notice a later observation of Jaeger in 1866, that the pigment epithelium of the retina in certain cases of myopia is Fig. 33. Fig. 33a. dragged over the nasal edge of the disc, and he announced that in many cases he had by the ophthalmoscope perceived that both the retina and the choroid were thus drawrn over (see Jaeger, pp. 66, 67 and Figs. 29, 30), while on the temporal side the membranes had been pulled away from the nerve edge and in this \x-Ay occasioned the crescent. Two years later Weiss examined two eyes one of which had M 5 D and the other a little less, and in which the so- called supratraction of the choroid had been observed during life. He subsequently examined three others and Herzog Carl Theodor has examined another. We will first give attention to the ophthalmoscopic appearances. We may have a simple crescent of small size attached to the tem- poral side of the nerve and marked by a pigmented edge (see Fig. 33). This may grow larger, and still larger (Fig. 34)t When equal to more than half the disc we may often see specks of pigment or choroidal vessels upon the surface. The crescent may not only ex- tend temporal-wise, but up and down. It may surround the whole nerve. In extreme cases the whole posterior region of the fundus 1 " Mittheilungen aus der Ophthalmiatrischen Klinik in Tubingen," 1880, Hft. 1, p. 231. 5 Ibid.. Bd. i., Hft. 3, p. 62. 3 Ibid., Bd. ii., Hft. 1, p. 56. 4 " Ueber die Einstellung des dioptrischen Apparates im menschlichen Auge," p. 61. 7 98 DISEASES OF THE EYE. shows thinning of the choroid and rarefaction of the pigment. Figure 34 indicates some of these conditions. What has been found in a slight case of myopia where the globe was 24| mm. long and the M probably not more than 3 or 4 D, is figured in the cut taken from Weiss's paper, Fig. 35 (" Mitthei- lungen," 1884, Taf. 11, Fig. 1). The condition may be described as a dragging of the papilla to the temporal side in which the retina, choroid, nerve fibres and sclera, the lamina cribrosa and vessels participate. The conspi- cuous element is the displace- ment of the choroid. At the edge of the opening for the pas- sage of the optic nerve, it is at- tached both to the sclera and to the lamina cribrosa. In fact the fibres of the latter belong in great measure to the choroid. The choroidal opening is elongated in the direction of the crescent and made oval; its nasal border reaches over the papilla and car- ries with it the retina. The supratraction may reach the middle of the disc. On the temporal side the choroidal edge is dragged Fig. 34. -*■■; &z&£*^ ~s Fig. 35. away from the disc, drawing with it the nerve fibres and fibres of the lamina cribrosa; the edge of the sclera becomes oblique and its inner surface is exposed, in proportion to the extent to which the choroid is retracted. Thus the crescent is formed partly by re- ERRORS OF REFRACTION. 99 traction and thinning of the choroid, and partly by a perspective view of the scleral canal, and upon it we have the commingled fibres of the optic nerve and lamina cribrosa. In moderate degrees of the crescent or conus, we simply have the opening out laterally of the scleral canal and there may be more or less pigment brought to view. But in higher grades there is real atrophy of the choroid with irregular islands of pigment, atrophy of vessels, some of which may remain or everything may have disappeared, except the elas- tic layer. The retina also suffers on both sides of the disc. The inner granule layer and lay- ers interior to it, will be intact, while the layers ex- ternal to it are deficient. The bacillary layer is de- stroyed both on the supra- tracted and on the crescent side, and this explains the enlargement of the blind spot which characterizes such cases. It is seen in Fig. 35 from Weiss that on the nasal side the retinal pigment has been drawn over the edge and turned up; this will be seen by the ophthalmoscope as a dark border. On the temporal side the choroidal edge where it becomes more nor- mal, also shows some in- crease of pigment, and the damage to the outer layers of the retina is usually more extensive than this limit. Figs. 36 and 37 from Jaeger show the same changes with less detail and are instructive. In advanced cases wThere a crescent has been converted into a ring of atrophy, though no traces of it can be seen by the unaided eye, the microscope shows the presence of supra- and also re-trac- tion, or that the papilla has been pulled in all directions. Stilling explains the variations in the direction of the crescent, by the trac- tion of the fibres of the superior oblique when its tendon happens to reach more or less to certain parts of the circumference of the nerve. It is of course understood that a bulging of the sclera occurs at the posterior pole which may be either broad or sharply defined. While the mechanical displacement with textural atrophy 100 DISEASES OF THE EYE. is going on, changes occur both in the sheath of the nerve and in the adjoining parts of the choroid. The intervaginal space is greatly distended and chiefly upon the nasal side (see Figs. 36, 37). To this Donders called attention. The sclera becomes thin and the pig- ment of the choroid is absorbed. Added to this is degeneration of the vitreous; it becomes liquefied, either so as to form larger or smaller cavities in its substance, or it will be separated from the retina by a layer of fluid. The hyaloid membrane may be split into two or more layers and the membrana limitans of the retina be- comes brittle and easily separated from the deeper layers. Fibres and cells and detritus float in the fluid vitreous and cause the shadows called muscoz voli- tantes, of which myopes so constantly complain. In its anterior part, the retina in severe ca ses is found to have become, as it is called, cede- matous, i.e., the layer of inner granules has been dis- tended into spaces which are filled with a coagulable fluid. The ciliary muscle of the myopic eye is charac- terized by the fewness of its circular fibres, while the meridional are in large number and reach far back- ward even beyond the ora serrata. Herzog Carl Theo- dor says that in some my- opic eyes the circular fibres are in reality not wanting, but are pushed aside and crowded together into a small space and for this reason may be overlooked. In this sketch are embraced most of the points of the real path- ology of myopia. The explanation of the mode of occurrence of the crescent, assigns to it an entirely mechanical and not an inflam matory origin; the evidence that the phenomena are the result of pressure enables us to impute the real cause to the extrinsic mus- cles of the globe. The part which can be played by the ciliary muscle is evidently nothing more than resistance to the stretching at the posterior pole, while itself becomes elongated and' is really caore a passive than an active agent. Fia. 37. ERRORS OF REFRACTION. 101 Besides degeneration of the vitreous to which allusion has been made, we have in advanced cases, cataract, beginning by preference at the posterior pole of the lens and evidently due to imperfect nutrition. The whole of the choroid may take part in the atrophy in extreme cases, the pigment cells becoming emptied of pigment, the chorio-capillaris and the middle layer of vessels becoming par- tially obliterated. More damaging is the occurrence of choroidal changes at the region of the posterior pole and even in the macula itself, where sometimes a distinct spot or group of spots of atrophy appears (Fig. 38). The effect upon vision is generally disastrous, causing a central scotoma. Even when very faint traces of choroidal lesion exist, or perhaps none can be seen, the cones in the macula may be- come separated and deranged so as to cause straight lines to appear crooked—metamorphop- sia. Hemorrhages are not in- frequent m advanced myopia and too often in the region of the macula. The most deplor- able occurrence, and which af- fects myopic eyes more than any other is sub-retinal effusion, or detachment of the retina. This destroys vision over an extensive part of the field, or perhaps in toto and is rarely amenable to treatment. It will be considered when speaking of diseases of the retina. Besides the troubles within the eyeball, there are to be men- tioned, the frequent troubles of the muscles, inequality of the eyes (anisometropia), and astigmatism. As to muscular incapacity, it is the rule to find it in high degrees of myopia. It is the result of being obliged to converge to a point too near for the muscles to permanently maintain the effort. The longer the axis the more difficult does it become to turn the eyeball inward. The interni must contract extremely, the externi are stretched and wrap around the globe and even the optic nerve in extreme conver- gence must suffer traction on the outer side of its sheath. The result of these hindrances is that insufficiency of the recti in- terni and positive diverging strabismus are frequent complications. On the other hand we also meet with strong degrees of converging strabismus in the higher grades of M. It is possible often for myopes to direct one eye up and another down, as shown by their unusual power of counteracting the diplopia caused by putting a 102 DISEASES OF THE EYE. vertical prism before one eye. Their grasp upon binocular vision is. much feebler than that of other persons. When the globe is much lengthened as, for instance, to 28 or even 30 mm., such an ellipsoid manifestly rotates with difficulty in a cavity whose shape is some- what similar. The centre of motion is displaced and in most cases is farther from the posterior surface of the sclera than in the em- metropic (Donders, p. 404). These troubles will be again adverted to. An apparent strabis- mus con vergens is often seen in myopes, because the line of fixation is from the shape of the cornea liable to fall to the outer side of its axis. In other words the angle gamma is either negative, or if positive is very small. (See page 14.) Weiss presents this in a diagram of one of the eyes which he examined. In great myopia the radius of the cornea becomes longer than usual, in harmony with the general distension. In the last degree of myopic change the lens becomes partially or wholly cataractous, and, because of fluidity of the vitreous, is liable to be luxated backward or downward. Intraocular hemor- rhages are prone to occur. In extreme cases the distention of the eye attains the condition called hydrophthalmus, and it may be difficult to say what part of the result is to be ascribed to a genuine irido-choroiditis, and what to the processes of simple myopia. Enucleation may then become a necessity. In external appearance myopic eyes often attract attention by their prominence and their observable ovoid form. Usually the pupils are large and inactive, but in all these particulars the contrary conditions may be true. The strictly congenital cases do not differ in essence from those which reach a high development in later life, and we need make no special reference to them beyond what has been said. Prognosis.—For practical purposes we may divide cases of myopia into classes according to their degree and their progress— into the moderate and the extreme—into the stationary and the progressive. The acutely progressive are by some described as malignant myopia, a name which seems for several reasons objec- tionable. We can recognize M amounting to 0.5 D, and as the far- point is then at 80 inches there is a manifest lack of clear distant vision. Even up to 3 D the error may be called slight. From 3 D to 6 D it may be called of medium degree, while all above 6 D are to be counted extreme and therefore serious. Horner well says, great myopia is the more dangerous the younger is the subject. Every practitioner can substantiate this; and he also says that the dangers of high myopia are most threatening in the later part of life, i.e., after 50 years of age. Then come vitreous degeneration, cataract, and subretinal effusion. For myopia below 4 D which has reached its maximum and is ERRORS OF REFRACTION. 103 stationary, there need be no anxiety as to the welfare of the eye, and both acuity and working power are often admirable. If it be- come stationary between 4 D and 8 D acuity is often slightly defi- cient, viz.: f or \, and the working power may be good or otherwise. Muscular troubles and astigmatism are apt to be present, but prognosis is not serious. When above 8 D the case is grave and the future will be influenced greatly by the health of the person, his surroundings and the extent to which he uses his eyes. In his statistics of blindness Cohn sets down 10$ as due directly or in- directly to myopia. He includes cases in which one eye only is blind. Diagnosis.—Remarks very similar to those in discussing hyper- metropia might be repeated. We test for distance by glasses and found the diagnosis conditionally upon the fact that concave glasses give normal acuity. It is not proven by this test, because with defective acuity there may be great myopia, and with perfect acuity thus procured, there may be no myopia. We must resort to the objective tests; the direct ophthalmoscopic method, or to Cuignet's method. Spasm of accommodation simulates M, and. as said before, while it usually disappears in the dark room, in special cases it still persists. When a doubt exists, one may more will- ingly resort to atropia than is admissible in either H or E. The occurrence of myopia from excessive curvature of the cornea is not to be forgotten, and will be especially mentioned under coni- cal cornea. The refraction is always irregular, and the error will betray itself by the shadow test, and with absolute certainty by the ophthalmometer of Javal and Schiotz; under oblique illumina- tion and by direct ophthalmoscopy it will usually be discovered. Prophylaxis.—Because myopia is for the most part an acquired anomaly and dependent, as has been shown, on excessive use of the eyes during the tender years of life, it is imperative to set forth the methods which can be employed to prevent or restrain it. Efforts in this direction are sometimes met by the objection that the error is hereditary and therefore the attempt is useless. Loring1 ably discusses this point; Tscherning and Landolt review what others have written. It is very difficult to get statistics of real value, but this maybe said, that the predisposition maybe hereditary, but that the determining causes are acquired and largely preventible. The cases which are congenital, and they are generally those of high degree, are very seldom hereditary. With the clear evidence that the error is brought about bj7- improper modes of life and of use of the eyes, preventive measures become imperative. The first thing is to promote a vigorous state of health, and in this all that relates to home hygiene, to food, air, sleep, and exercise, are to be regarded. Second, the arrangements in schools and the hours of 1 Transactions of International Med. Cong., Phil., 1876. 104 DISEASES OF THE EYE. studv, the light, the air space, the height of benches and desks, the distribution of study hours and play, the print of books, atti- tude in reading and writing,—all these are potent in their influence. On these points, Cohn and Fuchs, Berlin and Javal have writ- ten elaborate monographs and Cohn1 gives the literature of the subject. In the United States there is need of attention to the conditions of school life in many particulars, although our school houses are free from many of the evils complained of in continental Europe. As regards the hours of study and of play respectively, we are not so much at fault as are the Germans, but the tendency is to over taxation and therefore myopia. Frequent intervals of rest are most important, and children can naturally be better cared for in small than in large classes. Imposing long study hours out of school is another hurtful practice. Reading by dim light at home, by firelight, at twilight, sewing and embroidery, are things to be prevented. Certain trades and occupations have a mischievous effect. The most conspicuous are the type setters, whose ratio of myopia is nearly as high as that of the higher students. Watch- makers and jewellers have been shown to be little subject to the error because they work so much with a magnifying lens and with- out convergence and without much movement of their eyes. The great factor in preventing myopia is cultivation of out-door life and its consequent promotion of health and use of eyes upon distant objects. It is known that the English have a lower per- centage of myopia than exists on the Continent, and it is fair to connect their exemption with their fondness for out-door sports. Among us as Americans the same tastes exist, and not only for this reason, but because of our better conditions of existence, wre should have less of the evil. In our cities we have little advantage above other nations, although the native population in the cities is less prone to myopia than the children of Germans (Loring). Diirr's2 examinations found spasm of accommodation among only 11 out of 133 myopes; i.e., 7.3$. Latent A more than 1.66 D he reckons as spasm. In 30$ there were choroidal changes. He lays the greatest stress on the undue proportion of working hours exacted from children. He lays, as does Yon Hippel, less stress on imperfect arrangements in the school buildings, than upon simple overtax- ation whether at home or at school. He compares the total number of school hours demanded of children between the ages of 10 and 19 years in England, France and Germany; they are 16,500 19 000 20,000. Hours of recreation, are, in England, 4,500; in France. 1,300- in Germany, 650. It is also shown by a curious table, p. 145 that the more gifted scholars, compared to their less brilliant comrades are near-sighted in the ratio of 32 to 38. 1 Lehrbuch der Hygiene des Auges, 1891-92. a L. c. p 141 Noyes' " Diseases of the Eye." Plate I. ERRORS OF REFRACTION. 105 In describing the ophthalmoscopic appearance of the optic nerve in myopia, the situation of the choroidal atrophic crescent has been described. We may now call attention to certain less frequent anomalous conditions which resemble this lesion, yet must be dis- criminated from it. They are most frequently associated with myopia, and in many instances with myopic astigmatism and hence may here be introduced. That we sometimes find an ap- parent crescent on the lower side of the nerve has been referred to. A close inspection of these cases shows that the crescent may sometimes be divided into two parts, of which the upper part is gray and the lower whitish. It is easy to recognize in many cases that the crescent is an oblique surface or pit. In fact these cases are spoken of as coloboma of the sheath, that is of the scleral canal of the optic nerve. To this may be added a real choroidal crescentic atrophy. The lesion is essentially congenital. It is usu- ally associated with amblyopia. One eye only may be affected. Of the illustrations on Plate I. instances of this type are Nos. 2, 3, 4, 5, 6, 8, 9, 10. In No. 1, a physiological excavation is unusually situated, viz., at the lower edge of the disc, and we also have the crescent below. In No. 7 the lower and outer half of the disc is much flattened and merges into the crescent. Besides the anomalies mentioned, others are to be noticed, viz., that in No. 1 the vessels emerge in a direction contrary to the usual fashion, i.e., toward the nasal side instead of toward the temporal side. In R. No. 6, the trunk comes out as three branches instead of two. In Nos. 8 and 9 the vessels are peculiar. In 12 is a large choroidal atrophy and the refractive state of different localities is designated. This evidences distinct local staphyloma. In No. 11 is depicted a coloboma of the macula lutea: viz., the large central white surface upon which are pigment spots. Near it are two small circular patches of choroidal atrophy. Beneath the disc is a crescent. A case of this type I have never seen. Loring1 has figured a case, and refers to several. It will always be difficult to decide between an acquired and a congenital lesion of this kind. Coloboma of the optic sheath was first described b3r Liebreich:2 see also Nieden.3 In No. 13 is presented the very rare anomaly of a mass of con- nective tissue covering the principal part of the papilla. The above illustrations are taken from a paper by Prof. Fuchs, Graefe's Archivfiir Ophth., Bd. XXVIIL, Abth. 1, S. 139, 1882. 1 Loring: " Text-book of Ophthalmoscopy," p. 94. 2 " Atlas d. Ophthalmoscopies' Taf. xii., figs. 1, 2. 3 Kn;ipp's Archives of Ophthalmology, vol. viii., p. 501. 106 DISEASES OF THE EYE. Treatment—This divides itself into (1) the hygienic, (2) the opti- cal, and (3) the therapeutic, What has been said about prophylaxis includes the hygienic measures to be adopted when myopia has begun. There must be such a reduction in the hours of study and of close application as shall tend to diminish the rate of progress. Entire abstention might be necessary, but can seldom be enforced. The inclination to read for amusement must be checked and every- thing to promote health be resorted to. If there be a delicate or strumous constitution, especial pains must be taken by food and habits and appropriate medication to build up the tissues. It is by no means always possible even with the most careful management to prevent the increase of the error during the years of juvenility. I have followed a number of such cases and not been able to pre- vent the increase, but have probably been of service in restraining it. If the wisest efforts can only partly control the progress of the error we are not therefore to cease to attempt its control. Upon students in colleges and high schools advice should be incul- cated, and they must be convinced of its importance. Occasional seasons of rest are of importance, say for two or three weeks. They give time for the intraocular circulation to become regulated and for the muscles to gain repose. Much stress has been laid upon the value of atropine in checking myopia. But this remedy has now few supporters and the most that can be claimed for it is that under its use the degree abates about 1 D. This will not be a per- manent decrease, the ordinary tension soon returns. It gives a good opportunity for examination, because it helps to enforce ab- stention from use, and if the far-point be inside of 20 inches, it is no great annoyance, and I not infrequently use it. Abandonment of near work is the essence of the benefit, not suspension of accommo- dation. The corrective treatment is in the selection of glasses. If with. unaided eye any letters on the card are read at 20 feet, the degree is not great. If no letters are read, an approximate idea is gotten by noting at what distance the person holds the book in reading Snellen 2. Begin with trying, on one eye at a time, the weaker numbers. If strong glasses are being used, viz., above — 6 D, and the vision is nearly corrected, try whether sight is helped by hold- ing the glass nearer or farther away. If the former, it is too weak; if the latter, it is too strong. Myopes are often sensitive to an in- terval of fa or less. With too strong a glass they complain of being dazzled, and shrink from the unwonted brightness of objects. Much respect is to be paid to their impressions; but, when they have been wearing inadequate glasses, they are liable to mistake the surprising distinctness conferred by a proper glass, for a strain of over-correction. It is often impossible to give them V = ^-°- ■ but ERRORS OF REFRACTION. 107 before admitting this, careful inquiry is to be made for astigmatism, and the state of the fundus minutely explored by the ophthalmo- scope—especially the region of the yellow spot. Moreover, in doubtful cases the patient should have the benefit of atropia—using a solution gr. iv. ad 3 1. (1 to 120) several times. In seeking the best correction the danger is of getting too strong a glass, which will excite tension of the ciliary muscle. To this, as a rule, myopes are very sensitive. Among children who chose their own glasses it has been found that in from 19$ to 37$ (Erisman, Cohn) they were too strong. The same is not infrequent among adults. Many circumstances are to be considered in giving concave glasses. 1st. The degree of error. 2d. The quality of sight. 3d. The occupation and necessities of the person; the age, the sex. 4th. The state of the muscles. 5th., Whether the eyes have equal value. 6th. The condition of the in- terior of the eye, which is, perhaps, included in quality of sight. With per sons whose error is small, glasses are usually wanted only on special occasions, and none for near work; they care only for eye-glasses. Even with — 5 D some myopes care little for them, and if they do use them, complain that the habit of using them disqualifies them for as good discernment without them as they possessed before. This is simply an alteration in mental habits and not in sight. As a rule, however, persons having be- tween 4 and 10 D gladly avail themselves of glasses for uninter- rupted use. But when glasses are above 6 D some complain of fatigue from their continuous wear. This may be due to mus- cular fatigue, to anisometry or simply to the continuity of atten- tion which sharp sight induces. The value of this factor can hardly be appreciated by the emmetrope. To the myope taking off the glasses is sometimes like going out of the blazing sun into the shade. A large latitude must be allowed for idiosyncrasj^. Where the very high grades are reached, viz.: above 10 D, generall}- the person wants the full correction. Of course we must be governed by the state of the interior of the eye and the acuity of vision. But even when there may be a large crescent and other choroidal lesions, if the process be substantially stationary or slowly pro- gressive, I have found it best to give the full correction. There is less effort with the glasses than without them. One may often wisely impart a blue tint to the glasses, because from a large crescent or a patch of choroidal atrophy, light is reflected and dif- fused within the eye, the effects of which the blue color somewhat assuages. It need only be added that one should always be vigilant to dis- cover astigmatism complicating myopia, because it often makes a great difference in the acuity of sight. A glass may easily be chosen 108 DISEASES OF THE EYE. too strong because of an undetected astigmatism. The concurrence of the two errors is very frequent. In regard to giving concave glasses to children some special remarks are proper. They rarely need them for near work; for distance they require them to see maps and the blackboard in school and for such purposes. If the error be below 2 D they may get along by coming to the front, but when above that they should have spectacles and wear them most of the time. If the error is above 4 D the glasses should be worn constantly when the subject is 13 or 14 years old. They have an important influence in mental habits and character; they do not, in my judgment, when well chosen and with no special contra-indications, hasten the progress of myopia. They keep the working point at a suitable distance and by developing the power of accommodation assimilate the per- son to the emmetrope. It is, of course, assumed that there must be no tendency to unnatural approximation of the work permitted. For most myopes it is necessary to gradually become habituated to glasses. They may wear them for short periods until they be- come accustomed to them. What has been said applies for the most part to distant vision. We are sometimes obliged to order a special glass for near vision. This happens in persons whose accommodation is feeble either from want of use or from age, or whose myopia is high. It may be for playing the piano, for writing, especially with book-keepers who must cast their eyes over two or three large account books. How shall the glass be selected? A simple calculation will determine. Take the distant glass as a basis. Let it be 6 D, which we will call 7". The working point is to be at 20" = 2 D. We have 6—2 = 4 D. A glass 4 D will bring the near-point to 20" and will meet the need. Or, if the working point is to be at 1 foot which is f$ = 3| D we may give 3 D. The middle-aged myope and likewise the younger will do near wTork without glasses provided the near-point is not inconveniently close. It can happen with slight M that after middle life, a convex glass is required for near work, and myopes of higher grades reduce the strength of their glasses or abandon them when the time for presbyopia arrives. But distant vision does not of necessity become improved. Myopes suffer much from muscular asthenopia and especially from insufficiency of the internal recti. With many who have large error no attempt is made to maintain binocular vision for the near. They put off their glasses and use one eye only, while the other is allowed to diverge. In this way, despite the inconvenience of hold- ing a book very near, many read for hours in comfort. But with others there is an attempt at binocular vision which cannot be maintained. Hence they have pain and asthenopic irritation. Fre- ERRORS OF REFRACTION. 109' quently this can be completely relieved by choosing a weaker glass suited to the working point. In other cases additional relief can be had by decentciing the glasses from the median line. Sometimes a combination of abductive prisms and concave glasses can be hap- pily made. Prisms can seldom be made stronger than 5° or 7° be- cause they become too heavy. It is important to examine when asthenopic symptoms exist whether there be any tendency to devi- ation of one eye in a vertical direction. This can be told by a can- dle at 20 feet with a red glass over one eye and a strong abductive prism over the other, held accurately in the horizontal position. If the two flames are not on the same level, use a prism to correct the deviation, and this prism should be incorporated in the glasses to be worn. I have known an error of 2° make a patient extremely uncomfortable. But if the muscular error be of a certain amount, resort must be had to an operation, i.e., tenotomy of the antagonist, for its relief. To this reference will be made later. Here it is proper to say, that the only indication which to me is sufficient for this opera- tion is asthenopia of marked type and which other proceedings, faithfully tested, have not relieved or seem wholly unlikely to re- lieve. Tenotomy as a means of diminishing or arresting myopia has been practised, but it has no warrant in the results which it produces. It can do much harm and has done little, if any, good. Many times the choice of glasses for a myope is an intricate problem, demanding not only technical skill and knowledge of pathology, but also good sense and general wisdom. More active measures will be in order when a sudden increase appears, and with it symptoms of retinal irritation with congestion of the nerve, with floating bodies in the vitreous and a retraction of the choroid which by its size and the elongated look of the vessels on one side and their crookedness on the other shows the posterior staphyloma to be increasing, and a subacute inflammatory condition to be in progress or impending. Then prolonged abstinence from work, say for six weeks or longer must be enforced. The artificial leech, or in lieu of this two ordinary leeches, may be applied to the temples at intervals of four to six days. This cannot be often re- peated. The milder saline purgatives, especially the mineral waters, may be used, and as an especially efficacious agent pilocarpine may be given. Care must be taken with the last mentioned, if subcuta- neously injected, not to give a dose too large. One-sixth of a grain of the muriate of pilocarpine will generally do no harm to an adult, but it has been known to cause great prostration by reducing the heart's action. The value of iodide of potassium and of corrosive sublimate will be in the ratio of visible exudations in the fundus or may be decided by the acuity of vision. 110 DISEASES OF THE EYE. If the vitreous be ver}- hazy and perhaps at the same time the lens, this implies a more acute inflammatory process and might have been mentioned above. For this Horner recommends para- centesis of the anterior chamber, but this remedy is to be used with caution, because the sudden abatement of intraocular pressure is followed by a prolonged increase of congestion. The clinical acute- ness of Prof. Horner makes the mention of the proceeding justifi- able. A course of treatment thus outlined will have to be modified by the age and health of the person. If weak and young, drastic measures would only aggravate the case. Then the use of smoked glasses, employment of atropine to insure the greatest rest of the eyes, dry cups to the temples and general hygiene will be all that may be possible, without confinement to a dark room. It is also important that persons in whom myopia makes rapid advance should be examined every three months and if needful undergo a series of suspensions from eye work for a month at a time. In some cases of this kind a long sea voyage has proved eminently useful. The cases of high myopia in very early life, especially when it cannot be attributed to overwork, are the least susceptible to treatment and often there are no rational indications of treatment except of the hygienic kind. The stage of inflammation may have given place to that of atrophy, and often we see these deplorable subjects only in this period. At this epoch there is very little value in medication. A patient highly myopic and knowing something of the perils of his position is often extremely excitable and takes alarm at tri- fling symptoms—a slight conjunctival swelling, or a more than usually distinct vitreous shadow, brings them in terror for advice. Tact and gentle handling and inoffensive applications, a weak lotion of borax, a mild stimulating liniment to the forehead, and placebos generally are the soothing influences which are suitable. Should a spot of hemorrhage occur, perhaps in the macula, it is rather an index of weakness of the vessels than of undue deitermi- nation of blood. It is most likely to occur in the cases of dissemi- nated choroidal atrophy or general thinning of the membrane, and in which there are pigment deposits intermingled with atrophic spots. Treatment is chiefly rest and avoidance of light, with very mild derivative remedies. The blood is absorbed slowly, requiring weeks, and afterward there will remain a white spot. Scotoma occurred at the onset of the mishap and this may grow smaller, but will not wholly disappear, and even if it should, metamorphopsia is likely to ensue. Of detachment of the retina it is not now necessary to speak in detail. Such treatment as can avail has been related when ERRORS OF REFRACTION. Ill speaking of the antiphlogistic proceedings. Evacuation of the fluid by puncture of the sclera has questionable benefit. See chapter on this subject, p. 630. The inequality between the two eyes which in myopia is not in- frequent, is often a source of trouble. Sometimes a sufficient acuity can be given to each eye b}T its proper glass to enable both to work in harmony; at other times one is so amblyopic as to take little part in vision, and its error may be so high as to render correction valueless. An essential consideration is to carry the working point farther off. To some myopes strong light is a distress, and their glasses may be tinted a light blue. To some the constant observation of objects is a weariness—they prefer to take off glasses and remain in ignorance of what is about them until their eyes are rested. Many are sensitive to the form of the frames, their weight and ad- justment, and the eyelashes must not touch the glass. All these points deserve attention. Some persons affect the wearing of a single glass which they have learned to hold in place by nipping it with the brow. If such have two equally good eyes, which gener- ally is not the case, such a practice is no less damaging to the eye than offensive as a mannerism. The above description of the possible lesions of myopia is calcu- lated perhaps to make the picture of near-sightedness too gloomy, because so many woeful conditions are grouped together. The very large proportion of myopes escape all such disastrous occurrences; but it is highly important to convey the impression that myopia may be more than a mere inconvenience or trifling defect, because it does embrace such sad possibilities. ASTIGMATISM. As. When the refraction is such that rays emanating from a single point cannot be brought again to a focus as a point, on the retina, this state is astigmatism; of this there are two kinds, the regular and the irregular. The latter is caused by opacity of the cornea or lens, and does not admit of satisfactory correction, although it can sometimes be mitigated. The former is chiefly dependent on ab- normal curve of the cornea or lens, or want of homogeneousness in the lens, and is correctible by cylindric or spherico-cylindric glasses. The defect ma3r be acquired or congenital; irregular astigmatism in the cornea is an acquired error, and some rare cases of regular corneal a stigmatism are acquired; but, as a rule, the regular astig- matism of the cornea is congenital. Acquired astigmatism in the cornea, where no opacity exists, comes from conicity of the mem- brane, or happens after tenotomy of muscles, or after wounds of 112 DISEASES OF THE EYE. the cornea, iridectomy and extraction of cataract. But these cases are a minority of the whole. Of correctible astigmatism the greater portion are congenital cases. Objection is sometimes made to this statement because the error does not always announce itself until middle life. The explanation is that the accommodation can conceal a considerable degree of error until its vigor begins seri- ously to decline. It is also to be said that a small degree is natural to almost every one, varying from 0.25 D to 0.75 D, and because the radius of the vertical meridian of the cornea is shorter than that of the horizontal. We ,have occasion now to treat only of regular astigmatism and without regard to its locality in the lens or in the cornea. Consist- ing as it does in a want of uniformity in the radii of the meridians of the media, this error manifestly may complicate either emmetropia, hypermetropia, or myopia. For this reason we have simple astig- matism, either hyperopic or myopic; and compound astigmatism, both hyperopic and myopic; and lastly, there may be mixed astig- matism, in which either hyperopia or myopia may predominate. The symbols of these several conditions are as follows, as they have been given to us by Donders. To him we owe the systematic study and development of this subject, which he made with as much com pleteness as did Helmholtz the theory of the ophthalmoscope. We have: 1st, myopic astigmatism, Am; and compound myopic astig- matism, M + Am; 2d, hyperopic astigmatism, Ah, and compound hyperopic astigmatism, H -f- Ah; 3d, mixed astigmatism, with pre- valent M, viz., Amh, and with prevalent H, Ahm, or both M and H may be alike. Whatever may be the length of the optic axis, it is evident that the refraction cannot be homocentric, i.e., from a luminous point the rays cannot again be brought to a point. On the contrary, the focus, instead of being in one plane, is stretched over a certain length which is called the focal interval. This may be understood by the diagram Fig. 39 taken from Fick,. in which CD and AB represent the vertical and horizontal merid- ians of an asymmetric cornea viewed in perspective from an oblique position. The vertical meridian comes to a focus upon the axis at o and thence the rays diverge. The horizontal meridian reaches its focus less quickly, viz.: at o' and thence its rays diverge. The space between o and o' is called the focal interval. The form of this portion of the bundle of rays cannot be a cone, but forms a skew surface. There is no place within it where a punctate focus is formed, but there are linear foci, one at o and the other at o'. These, however, are not mathematical lines, because at both these places there are other rays which do not join with them. It is im- possible to indicate in a diagram the form of the bundle. If, how- ERRORS OF REFRACTION. 113 ever, we place a screen across it at the points marked 1,2,3, 4, 5,6,7, perpendicular to the axis, we shall get the following series of lumin- ous surfaces as shown on Fig. 40—beginning with a vertical oval, 1,2, then converted to a vertical line, 3, where the rays are focussed which belong to the vertical meridian; then again comes a verti- cal oval because the vertical rays are going apart; then quickly comes a place where each meridian has equal separation from the axis and the figure is a circle, 5; then comes a horizontal oval; and, lastly, a horizontal line where the rays in the horizontal me- ridian cross. All this is easily illustrated by using a spherical lens + 6" focus and adding to it a + cylinder 12 inches focus with which to throw the image of a flame or of a luminous round disc of Fig. 39. Fig. 40. ground glass on a screen—all the above changes will be verified if the axis of the cylinder is placed horizontal. The mathematical theory of this condition is intricate, and was developed by Sturm and has been further discussed by Knapp, and very lately by Mathiessen, who modifies slightly Sturm's theory. Knapp has made a model with silk threads of different colors which illustrates very admirably the phenomena. Becker has also done the same by letting fall a beam of light upon a spherico-cylindrical lens set in a glass tank filled with water rendered milky by nitrate of silver. The luminous track is displayed as a pencil of light ap- pears in a dark chamber reflected from the floating particles of dust. The form of the beam can be studied at leisure and all the sections shown which have been described. On a large scale the visual phenomena of astigmatism may be perfectly shown with the 8 114 DISEASES OF THE EYE. magic lantern by adding a very weak cylinder to the objective, viz., + 1 D, or + 0.75 D. It has been said that differences in the radii of the vertical and horizontal meridians of the refractive surfaces are the chief causes of regular astigmatism. To this must be added the want of exact- ness in the centering or collimation of the refracting media. This affects both the cornea and the lens. The geometrical axis of the cornea forms with the visual line the angle alpha, and moreover, as the line of fixation causes the eye to deviate still further from the visual line, the angle gamma (see page 14, Fig. 7) increases the asymmetry of the several surfaces. This want of collimation occa- sions astigmatism. It is exceptionally the case that the shortest focus of the media is through the horizontal meridian. This is some- times spoken of as astigmatism against the rule. Slight deviations from the vertical are very common. Astigmatism of the lens may increase or diminish that of the cornea. Javal1 has shown that a very small fraction of the total astigmatism is due to the lens; he has also shown that by accommodation the lens may partly or wholly neutralize asymmetry of the cornea. He, and before him Dobrowlsky, attributes this to unequal contraction of the ciliary muscle. In some cases of pretty high degree he finds about all the astigmatism in the cornea; what may usually be ascribed to the lens is not more than 1.5 D. He has revived attention to the con- trol which young subjects have over astigmatism, citing himself as an example, that with astigmatism = —2.5 D he could at 24 years of age see the stars correctly as others do. It is a frequent observation that slight degrees of the error first come to light during middle life. Latent and manifest astigmatism of course refer to the influence of the accommodation in concealing or modifying the error. Like hyperopia this distinction is of most importance in its slight de- grees and chiefly among young subjects. Simple astigmatism affects the emmetropic eye and may be simple myopic or simple hyperopic, Am or Ah. In Am one merid- ian is emmetropic, the opposite is myopic. In Ah one meridian is emmetropic, the opposite is hyperopic. (See Figs. 41,42.) The con- ditions are illustrated in the diagrams. Compound astigmatism belongs to the ametropic eye; if myo- pic, both principal meridians will be myopic, but one to a greater degree than the other, i.e., the radius in that meridian will be shorter. If the eye be hyperopic, both principal meridians will be hyperopic, but one to a greater degree than the other; i.e., its radius will be longer than that of the other. We have then, M -f- Am and H+Ah. (See Figs. 43, 44.) 1 See Annales d'Oculistique, 1881, ii., 14. ERRORS OF REFRACTION. 115 Mixed astigmatism exists in an eye whose axis is normal, but in one meridian myopia exists, while in the opposite hyperopia exists. In other words, in one meridian the radius of curve is shorter than normal, in the opposite meridian it is longer than normal. Accord- ing as myopia or hyperopia predominate, the cases may be desig- Fig. 41.—Simple Hyperopic Astigmatism, Ah. Fig. 42.—Simple Myopic Astigmatism, Am. Fig. 43.—On up. und Hyperopic Astigmatism, H + Ah. Fig. 44.—Compound Myopic Astigmatism, M + Am. Fig. 45.—Mixed Astigmatism, H and M equal. nated as Amh and Ahm. In Figs. 43 and 44 the form of the eye is made myopic and hyperopic—as compared to the remaining figures which are supposed to be emmetropic. The above are the subdivisions originally made by Donders and they are what we practically have to observe. In the figures H 116 DISEASES OF THE EYE. stands for the horizontal and V for the vertical meridians. The position of letters and of the dots in relation to the retina indicates the kind of error; in eyes having compound astigmatism one is represented as hyperopic (Fig. 43), the other as myopic (Fig. 44); in each case the vertical meridian has the shorter radius. In mixed astigmatism the axis is represented as emmetropic, while in the eye the myopic meridian, which is the vertical, has an equal error with the hyperopic; equality of H and M is less frequent than marked inequality. Instead of speaking of a shorter radius, it might be perhaps better for the present to speak of the shorter and longer foci, as these are what the diagrams represent. Inasmuch, how- ever, as the principal error resides in the cornea, the terms may be used indiscriminately. It is at the same time clear that ametropia and astigmatism are two distinct conditions, although they may coexist. It has been remarked that the meridian of shortest focus or of shortest radius is usually vertical. To this rule there are numerous exceptions, not only in obliquity of the principal meridians, but in complete reversal of the rule, so that the horizontal may be the strongest. Javal says of himself that he has this condition and that in numerous members of his family among whom the error prevails, nine out of ten have the horizontal meridian stronger than the vertical. The direction of the meridian has an important influence upon vision. One may understand it by putting before his eye a convex spherical, say of 2 D, added to a convex cylindrical of 3 D; there will then be the condition of compound myopic astig- matism, supposing the experimenter to be emmetropic. If the axis of the cylinder be made horizontal, the strongest meridian becomes the vertical; then objects will have their vertical dimensions lengthened because in this meridian rays come to a focus quicker than in the horizontal and have crossed before they reach the plane of the latter's focus. For this reason the ends of an object will be fringy, while the sides will be sharp. A series of dots in a vertical row will run into each other and make a solid line with blurry ends. If the axes be reversed to the horizontal, objects will seem broadened; the top and bottom will be well defined, the sides blurry. The dots remain separated, but extend laterally into brushes. With the axis in an oblique position, an elongation takes place in the direction of the strongest meridian or opposite to the axis. If glasses of an opposite type, viz., concave, are employed by which hyperopia is induced, the phenomena will not be so distinct because the accommodation will modify them; they will at the same time become reversed in reference to the axis of the cylinder. With the axis horizontal the strongest meridian also becomes horizontal and if one accommodate for this meridian the dots will be stretched in ERRORS OF REFRACTION. 117 a horizontal direction, and if for the opposite meridian they will be merged into a vertical line. From these experiments we can appreciate the symptoms of astigmatism. There is usually indistinct vision, acuity being reduced in accordance with the degree of error. If spherical glasses improve it, there will not be much difference in the value of two or three nearly equal numbers. The person may say that he has noticed a differ- ence in the distinctness of objects according to their form. A boy who required in one eye a cylinder +6" axis 90° and in the other + 8" c. axis 90°, told me that he could see the telegraph wire farther than he could see the pole on which it was stretched. The masts and spars of a ship show- similar differences to some persons. Some people have noticed that they found trouble in telling time when the hands of a watch were in certain positions. Such patients for the same reason find difficulty in reading certain letters. For in- stance, O on the card seems to be H, because with a strong vertical meridian the top and bottom are hazy and the sides black. With a reverse meridian of maximum refraction a C is imagined to be Z or cannot be made out. Dr. Little, of Philadelphia, has put into a card the letters which he calls confusion letters for astigmatics, and he has given the words FOOL and NULLIFIED, which are special stumbling blocks. In the test types such errors are to be heeded as significant. Similar to these mistakes is the difficulty which such persons have in reading Greek and Hebrew, because the characters are difficult for them to decipher. It is also charac- terisl ic that they hold books very close and their near-point is close for all kinds of work. They complain sometimes of confusion, but ignorant of the nature of their trouble and seldom analyzing their perceptions, they cannot describe exactly how objects appear, but they often complain of headache. In this respect astigmatics suffer greatly and so common is it, that an inquny into the refraction in cases of obstinate headache has become a routine question. Dr. Weir Mitchelll called attention to this as a neurologist in 1874-76. It was known to oculists long before. Want of quick perception is also characteristic, and this is the necessary result of their blurred retinal images. If they have chosen glasses, especially concave glasses, they wear them often tilted forward, by which means their sight is improved. By doing this their confusion ellipses are converted into lines, and the change is favorable to vision. The degree and kind of subjective symptoms will depend much upon the peculiarities of the person, and if the temperament be nervous and excitable the reflex and attendant phenomena are sometimes extraordinary. Many papers have been written on this text and elaboration is unnecessary. 1 American Journ. of Med. Sciences, April, 1876, p. 363. 118 DISEASES OF THE EYE. The name astigmatism was given by Dr. Thomas Young, who< carefully studied the subject and invented tests to detect and ex- hibit it, in 1793. If two convex cylinders be combined with their axes parallel they increase each other's power as cylinders. If they be combined with their axes transverse they neutralize each other as cylinders and compose in effect the equivalent of a spherical lens (not, however, in a mathematical sense). Such a combination gives a flatter field than a bi-spherical lens. A convex and concave cylinder of the same radius, if combined with parallel axes, neutral- ize each other and become the equivalent of a plate of plane glass. If they be combined with axes transverse they add to each other's power as a cylinder. Such a combination of a convex and concave cylinder has been employed under the name of Stokes' lens. When the axes cross obliquely the degree of astigmatism is between zero and the maximum of the two combined, and it increases as the obliquity passes into the transverse direction. The combination in. reality is equivalent to a mixture of a spherical and a cylindrical glass in every position save when the axes are either parallel or transverse. Cylindric and spherical lenses may be combined, so that we have concave spherico-cylindric and convex spherico-cylindric. Occa- sionally a bi-cylindric lens is ordered, as in some cases of conical cornea, but as a rule spherico-cylindric or plano-cylindric lenses serve the needed purpose. Diagnosis.—We have to ascertain the fact of astigmatism, its, kind, its degree, and the direction of the principal meridians. We may or may not employ a mydriatic, and we resort to both sub- jective and objective methods as for other kinds of refractive error. We try the acuity of vision, and prove how much may be gained by concave or convex spherical glasses. The deficit is not apt to be large, because high degrees of astigmatism are rare. We note whether the patient stumbles at certain letters such as O or F,. or L or N; and if vision reach f-g- and cannot be carried beyond, a weak cylinder of 1. or 1.5 D may be put before the spherical and rotated to see if at some point vision notably improves. This would prove the presence of astigmatism. But it is better to adopt a more systematic method to elicit and analyze the error. The best tests are those of Dr. Green, of St. Louis. Upon a diagram of a clock dial he places discs traced with lines and dots of various widths and arrangements. Each disc is centred upon a pivot and can be revolved in any direction. Out of a great variety of patterns I have learned to confine myself to two or three. The space between each hour is of course 30°. Put before the patient the one denoted in Fig. 46 and give the patient the weakest spherical concave glass or the strongest spherical con- ERRORS OF REFRACTION. 119 vex glass which he will accept, and ask him to say whether he sees all the lines of the figure with equal distinctness. One must urge him to give close attention and must also increase the convex or diminish the concave glass, so as to bring out the meridian of strongest re- fraction. This antagonizes his accommodation. If he have astig- matism he will state that along a certain diameter the lines are more conspicuous or stand out as the only ones of the figure. There may be two or three, or there may be five or six. The fewer and more prominent the greater the astigmatism. Let him point out between what figures on the dial (hours) the lines are found. Say they run between XII. and VI. This indicates the meridian of strongest refraction with the glass. Substitute for this disc an- other, like Fig. 47 and set the lines in the direction which the Fig. 46. Fig. 47. patient indicates. The lines are wide at their extremities and nar- row at the centre. If the glass he wears is suited to this meridian the patient should trace the white interval almost to the centre. If he do not, move the disc lightly in either direction. If this do not separate the lines more perfectly, modify the glass a little until the lines become well defined and separated within an inch or less of the centre. This determines the glass for this merid- ian, and it is to be noted. Between every hour on a clock are 30 degrees, and we have found the principal meridian to be exactly upon the vertical. Now turn the disc 90° and bring the lines to run from IX. to III. They are indistinct, light in color, ill-defined, not separated and the white interspace is short or invisible. Now diminish the convex spherical or increase the concave spherical until the pair of lines are made as distinct as before. Suppose in the direction from XII. to VI. the glass was — 3D, and now from IX. to III. it is — 5 D. The difference between them is, — 120 DISEASES OF THE EYE. 2 D, and this is the astigmatism. Suppose the glass at first had been -f- 7 D and now we have + 4 D, the difference is + 3 D, and this is the astigmatism. In the former case it is compound myopic, in the latter case compound hyperopic. It may have been that from XII. to VI. the glass was —2D, and when the line is reversed no glass is accepted or uncertain answers indicate that the patient is not sure—this is likely to be simple myopic astigmatism. There is great liability to think that a simple myopic astigmatism exists with the axis horizontal wrhen in truth the error is simple hyper- opic astigmatism with the axis vertical. Such a mistake is often made and the only assurance against it is in the use of atropine. We have found, we will say, —2D astigmatism. Let the patient have —3D spherical and give him another test card like Fig. 48 where 2 pairs of lines cross at right angles; set them in the proper diameters. Then put before the spherical a concave cylinder — 2D with its axis transverse to the lines from XII. to VI., and this will make each pair of lines perfectly distinct. For the other case of compound hyperopic astigmatism, let him have the + 4 D spherical to view the crossed lines and to this add + 3 D cylinder with its axis corresponding to the direction XII. to VI., and this will clear both the lines. The same thing will be Fig. 48. ™ , - , . ^ & effected by using + 7 D spherical and to it adding —3D cylindric with axis transverse to the di- ameter XII. to VI. Now with the combined spherical and cylindri- cal glasses let the patient try the test letters. A smile lights up his face as he runs glibly over what he had painfully failed to see. There is no more satisfactory experience than to witness the success of one's efforts in a case of astigmatism. If the examination proceed as described, the diagnosis is deter- mined and also the glass required, but such is not always the fact. Satisfactory vision is not always easily gained, and we must multi- ply the tests or resort to atropia, or what is better, employ objective methods. Mr. Bowman (see Donders, p. 490) found illumination of the eye by the mirror at two feet distance with rapid variation of its inclination, sometimes lead him to the discovery of regular as- tigmatism. What are the indications for the use of atropine ? In myopic astigmatism, both simple and compound, it is rarely necessary In marked compound hyperopic astigmatism it may often be dispensed ERRORS OF REFRACTION. 121 swith. In simple Iryperopic astigmatism it will often be necessary, and the same remark applies to mixed astigmatism. Practically the point in a given case, is to find out to which of these classes it belongs. Javal strongly insists that to use atropine and to correct the whole error is wrong practice. I cannot fully concur in this opinion. The degree of asthenopia and the visual acuity must be taken into account. In young subjects who enjoy good accommo- dation and who have not complained of severe symptoms the par- tial correction may suffice. But the presumption is not so much in favor of this decision as in the case of simple hyperopia. One must call to his aid the objective methods, and observe what may be the difference between the results according to them and according to the subjective test. If the difference be great, I have no hesitation in using atropia to full paralysis. It is true that the correction thus obtained is likely to be too strong for the patient to accept. But at the end of a week the subjective test may again be made and a glass selected Avhich will be satisfactory. The suspension of accommodation is, in my experience, a valuable therapeutic mea- sure in many cases of astigmatism. The enforced rest is servicea- ble and they are prepared to use their eyes and their glasses with greater comfort. There are other subjective tests which it is proper to mention. A most useful one is the letters of Dr. Pray. They are capitals composed of strokes which run in different directions for each letter. A patient points out the letter which is most black and clear, and the direction of the lines composing the letter indicates the direction of the meridians. Becker gives a set of parallel lines in triplets and placed in various meridians; also concentric circles which will ex- hibit a sector of distinctness contrasted with remaining indistinct- ness. There are many other ingenious test diagrams whose char- acter is similar. (See one by Dr. Oliver in Medical News, Oct. 6, 1883, p. 373.) Schemer's method of determining refraction as modified by Dr. Thomson is also to be considered, and it has value in the cases which are decidedly amblyopic, whether from conicity of the cornea or slight haziness of it, or from true amblyopia. Reference has been made to it on page 81. Consideration of cases in which vis- ual acuity can at the best be only very imperfect, will be deferred to a later page. Objective examinations are made by inspecting the fundus by the direct method of ophthalmoscopy, by Cuignet's method or the shadow test, and by ophthalmometry. The first is most available, the second has an approximative value, the third is extremely rapid and exact so far as corneal error is concerned and would doubtless be much used if the instrument of Javal and Schiotz were not ex- 122 DISEASES OF THE EYE. pensive. To detect astigmatism by the ophthalmoscope we simply take for an object a fine vessel running in the direction of one prin- cipal meridian and choose the glass, whether plus or minus, which makes it distinct, and then take another fine vessel running in the opposite meridian and find the glass suitable for that. Great care must be taken not to let accommodation either of subject or ob- server interfere. The difference between the glasses gives the as- tigmatism. Now set a cylinder before the patient which corrects the astigmatism, placing the axis in the proper manner, and in the ophthalmoscope make up the remainder of the refractive error by turning on spherical glasses and again examine the fundus. Now there should be a perfectly clear and bright image if the media are transparent. And this contrasts strongly with what was possible when only spherical lenses were employed. (It is easy to arrange a spring clip behind the mirror to carry a cylinder from the trial box, and this is provided in my ophthalmoscope. See Fig. 21, page 45). One can thus satisfy one's self not only of the accuracy of the refractive correction, but of the integrity of the membranes, which is very important in high degrees, both of compound myopic and of hyperopic astigmatism. If the error be high, the fundus before the suitable glass is found will have a smeared and streaky look, as if a brush of paint had been swept over it. The nerve will be pulled out into an oval form and the ends of the ellipse be fringy with the vessels drawn in the same direction; there can be no dis- tinctness in the detail of the surface. If the error be over-cor- rected, the disc will be elongated slightly in the opposite direction and the lines of distortion will be reversed. Not until the cylinder is introduced will the view be satisfactory. It is also useful to employ the inverted image to corroborate the diagnosis. By it, if the nerve were by the direct method oval, with the long axis verti- cal, the long axis becomes now horizontal. For this phenomenon to be well seen, the objective must be not less than 3" focus and it must be held at its own focal length distant. If nearer to the eye or farther from it, the inverted image will be less elliptical. The lens must be held exactly vertical and without any turning on its axis, else this will cause the disc to seem oval. To distinguish between an optic disc which is oval anatom- ically, from one which seems oval by reason of astigmatism, one must note its edges at the extremities of the oval. If they are sharp and well-defined, the shape is anatomical; if they are blurry or fringy, astigmatism is the cause. The shadow test (employing a concave mirror) shows astigma- tism in the following way: If the shadow move up and down in the same way as the mirror and with a certain rapidity, and when ERRORS OF REFRACTION. 123* moved transversely the shadow goes in a similar way with less rapidity, this indicates myopia in both meridians, but a greater degree in the vertical. If the shadow move " against" the mirror in one meridian, and with greater rapidity than the movement " against" the mirror in another meridian, this proves hyperopic astigmatism. In other words, if in meridians at right angles to each other the reflex and shadow move in different directions or with different degrees of rapidity, there is astigmatism. A very bright reflex and a shadow difficult to detect, but nearly linear and traversing the pupil very rapidly and in a direction contrary to the motion of the mirror indicates E in that meridian. The slower the movement the higher the ametropia; the more rapid the move- ment the nearer to E. If there be mixed astigmatism, the shadow will in one meridian move with the mirror and in the opposite meridian against it. A motion opposite to the mirror indicates either E, H, or weak M. To decide which of these is present, set a glass -f- 1 D in the trial frame before the eye. If the refraction be emmetropic, this glass causes myopia and the shadow should move with the mirror; if such be not the fact, the eye has H; if the shadow does now move with the mirror, the patient has either E or M. A glass +.5 D will decide whether there be E or M, and a stronger -f- glass will give an idea of the degree of H, until a glass is found which makes the shadow go opposite the movement of the mirror. Cylindric glasses may be put before the eye as spherical usually are until the phenomena are made to resemble those of emmetropia. See paper by Dr. Ferguson.1 Ophthalmometry, by the instrument of Javal * and Schiotz, is the quickest and usually most reliable mode of examination. An experience of eight years has given me the greatest confidence in it. The model now made differs from the original figured in the text, and in my judgment is less desirable. It has a large disc with so many lines and circles as to cause confusing reflections from the cornea. A plain black disc one foot in diameter is important and sufficient. Its essential parts are as follows. (See Fig. 49.) Two very bright objects, one a complete parallelogram and the other a parallelogram of the same dimensions, but with its long side cut away in the form of steps, p. 125, are made to slide on a curved bar and are placed before the eye so that each shall be reflected from the cornea. These reflections are viewed by a small telescope, and are doubled by passing through a Nicol's prism. Four images are in view as with a stereoscope, but the outside ones are neglected, and attention given to the two cen- tral ones. The patient's face is placed in a frame and is steadied 1 "Retinoscopy;" American Practitioner, Dec, 1882. • Annales d'Oculistique, Ixxxvi., July and August, 1881, p. 5; ibid., lxxxvii., May and June, 1882, p. 212; ibid., lxxxviii., July and August, 1882, p. 33. 124 DISEASES OF THE EYE. by a chin and forehead rest. The telescope stands upon a tripod which can be moved forward and backward to get the proper focus, and has a screw adjustment for slight variations in height: When the central images are sharply seen, the step-slider is moved until its bottom step comes into exact contact with the lower part of the parallelogram (see Fig. 50). The lower edges of the reflected images are brought into a straight continuous line by turning the bar which -carries the sliders and which revolves around the body of the tele- Fig. 49.-In this instrument electric lights are used, and a disc has been added to protect the ob- server. In other respects it is like Javal's model of 1882. scope. Having accomplished this, the position of the bar is read off upon an index which will place it, we will suppose, at 180°. Then the bar is turned 90° and the relations of the two images noted. If they have not changed, either by overlapping or separating, the curve of the cornea is the same both horizontally and vertically; if the images overlap in the vertical meridian, the radius of curve is in this sense shorter and there is astigmatism (see Fig. 51). If the images separate with the bar vertical, this meridian has a longer radius than the horizontal, and again there is astigmatism. Each ERRORS OF REFRACTION. 125 step in the step-slider represents 1 D, and consequently the amount of astigmatism is easily read off, and can be estimated to .25 D. By the ordinary arrangements errors of 6 D are measured, while by special adjustments much higher degrees can be determined. The portion of the cornea inspected is a central circle 5 mm. in diameter. It is assumed that the chief seat of astigmatism is in the cornea. Javal claims that between the total astigmatism as found by trial glasses and the corneal error the difference will not be greater than 1.5 D. It would be inadmissible to permit an error so great as this, while as a matter of fact so great or any import- ant discrepancy very seldom arises. It is chiefly found among the lower degrees of error, i.e., when less than 3 D. The axis of the principal meridian is quickly determined and will vary from that found by trial glasses by only a few degrees, usually not at all. We learn nothing as to the kind of ametropia nor do we know whether the cylinder should be plus or minus. Preliminary trial has already given an idea of the quality of error, and putting the □ □ Fig. 50. Fig. 51. cylinder designated into the trial frame we add plus or minus spherical glasses until the visual acuity is raised to the normal degree. Before testing by trial glasses the indicated cylinder may be put behind the ophthalmoscope and the real refractive situa- tion be objectively ascertained, and afterward the spectacle box will soon give us the requisite combination. A good illumina- tion is essential, and diffused surrounding light is cut off. There should be a screen at the observer's end of the telescope to shield his eyes. The whole problem may often be solved at a single sitting and without atropia. For rapid work and especially in public institutions this instrument is invaluable. For the young, the confused, the dull, the amblyopic, it is most excellent. It is not rare to discover, as Laqueur pointed out, that the curve of the cornea is not constant. It sometimes changes as we look at it, we note the images approach or separate instead of remaining still. They exhibit these oscillations under the action of the lids, and also if the upper lid is lifted off the globe, under the action of the motor muscles. Drawing on the lids at the outer angle will increase the corneal curves greatly. Hence we have an explanation of the un- 126 DISEASES OF THE EYE. certain findings in some cases of astigmatism, apart from spasm of accommodation. The cornea is thin and cannot resist external pressure. The same explanation will account for variation or in- crease of astigmatism with lapse of years: in fact, herein lies the beginning or suggestion of conical cornea. The ophthalmometer unerringly detects opacities and distortions in the form of the cor- nea, and thereby explains why the attainment of perfect visual acuity may be impossible. It also shows that the principal merid- ians are sometimes not at right angles to each other, e. g., one may be at 90° and another at 160°. The axis of the cylinder accepted by the patient will usually in such a case approximate the truly verti- cal or horizontal position. Aeuity will usually be below standard. A simple device which roughly points out these defects in the cor- nea is the so-called disc of Placido, which consists of a series of con- centric circles painted on a disc about 10 inches in diameter in black and white. (See Fig. 52.) It is held close to the cornea and the reflex viewed through a cen- tral hole with a lens 4" focus. Javal has applied the same to his ophthalmometer.1 It has already been said that astigmatism exists in many per- sons who have normal visual acuity and make no complaints. Especially will this be true of the young and vigorous and some- times with high degrees of error. Low degrees are often unrecog- nized until presbyopia approaches. Moreover, if the error be hy- peropic or myopic, with axis nearly horizontal, in both which cases lines nearly perpendicular are most distinctly seen, persons with notable error get on moderately well, because most objects with which we deal have greater height than breadth. Such is the case with type (Roman letters), and with trees, men, buildings, and the majority of objects. True, objects are exaggerated in height, but of this the person is un- aware. But if the axis is in the contrary direction, or if it be ■oblique, or if the two eyes are unsymmetrical, trouble announces Fig. 52. 1 Annales d'Oculist., Jan., Feb., 1883, p. 5; also Landolt, English ed., p. 328. ERRORS OF REFRACTION. 127 itself early. An attack of illness, chronic uterine disease, exces- sive eye-work, great grief, etc., will reveal astigmatic error, pre- viously unsuspected. I have also seen astigmatism, which severe uterine disease had brought to view, retire into obscurity and un- consciousness when by an operation the uterine lesion was cured. The glasses which the patient had with extreme reluctance con- sented to, were put away and satisfactory use of the eyes regained without them. The more pronounced are the asthenopic symptoms, the more searching must be the quest for astigmatism and the more accu- rate its correction. Then even slight degrees, 0.5 D, must not be neglected. No fixed rule can be given about correcting the full amount of error, yet this will be done in the majority of cases. If there be no asthenopic symptoms, we need only correct the mani- fest error; with slight symptoms this may also be the general rule, with emphatic symptoms full correction is demanded. In young subjects, as has been said, more may be left to the accommodation than with persons above thirty. But an error more than 1 D should not, in my opinion, be permitted to remain, even in young subjects. When strong cjdinders are first worn, the subject is often annoyed in growing accustomed to them, and as with high myopia may have to use them for short periods at first. For near work it is especially necessary to have the correction, and whether the glasses be the same which are used for distance will depend on the age and refraction. For one Avho is becoming presbyopic an increase in refracting power may be needed. For a myope a weaker spherical concave glass may be required. The rules in this regard are easily deduced from the ordinary require- ments of ametropia and presbyopia. In all cases, however, the same cylindric corrective will be demanded as for distant vision. In certain cases the glass for distance may be reversed for the near. For instance a person uses — 1.50cD with axis horizontal for distance and by presbyopia needs + 1.50s for reading. Instead of ordering + 1.50Ds 3 — 1.50 Dc, axis 180°, one may give + 1.50cD axis 90°, which meets the same need. Formerly cylindric glasses were cut circular and large that errors in setting might be corrected. Such ungainly binocles be- long to the time of unskilful opticians. It is wholly unnecessary to make a patient conspicuous by large and round glasses. They may be used either as spectacles or as nose glasses. Of course the former are more steady and trustworthy, but personal choice often decides this point. When used as eye-glasses they are apt to tip forward, and this makes a slight increase in the refraction in the vertical meridian. Sometimes this has to be taken into account. 128 DISEASES OF THE EYE. With strong cylinders patients are obliged to look straight forward through the middle of the glass. A sidewise look gives distortion and it cannot be avoided. Therefore they have a more restrained field of vision than ordinary ametropes. It happens sometimes that astigmatics have very deficient ac- commodation. I have been obliged in some cases to order for near work a glass which represented the whole amount of A which was needed. This has occurred in persons whose error was not cor- rected until they had come to thirty-five years of age. In writing a formula for spherico-cylindric glasses the following notation is employed: say, - 3.0 s. C - 1.5 c, ax. 180°. The sign C meaning a combination of the spherical and cylindric surfaces. For mixed astigmatism we may have either a spherico-cylindric or a bi-cylin- dric combination, viz., for instance: 1.0 s. C +2.5 c, ax. 180°, which can also be expressed by - 1.0 c, ax. 90° C + L5 c, ax. 180°. The combination of cylinders of opposite qualities with axes at right angles gives a wider and flatter field than belongs to spherico-cyl- indric glasses. Hence such an arrangement is to be preferred in considerable degrees of error. Slight degrees of mixed astigmatism are not rare. The above notation was suggested by Donders and is consider- ably used—nevertheless a printed form is to be preferred in which. each kind of glass has a line for itself, as for example: O. D. Spherical + 3 D. Cylindrical + 2.5 D, axis 180° Prism. base O. S. Spherical + 2.5 D. Cylindrical + 2.0 D, axis 170° Prism. base Space is given for inserting the use of a prism. The opticians print such blanks, and often a semicircle is added, laid out in de- grees to assure accuracy. The inter-pupillary distance, and some- times notes as to the height of the bridge and other details are provided for. These points are not too trivial for the oculist's attention, although he may place reliance on the skill and careful- ness of his optician. Anisometkopia. We are in the habit of examining each eye separately and choos- ing the glass which each requires. We meet cases of inequality of the eyes, and when a difference of 1 D exists, the name anisometry is employed. Differences far higher are met with. As, for example, with monocular aphakia and in myopia one eye may exceed the ERRORS OF REFRACTION 129 other by many dioptries. I have records of many such cases. It can also happen that the eyes may have opposite kinds of refraction, viz.: one be hyperopic and the other be myopic; or E in one and H or M in the other. This I have called antimetropia.1 The behavior of dissimilar eyes may be of three kinds: they may combine in binocular vision; one may be used for distance and the other for the near, or one only may always be used. If they combine in binocular vision; this may be true for distance and not for the near point. It is remarkable how great differences can sometimes be comfort- ably harmonized. With a difference, say of 3 D, there is necessarily a combination of one sharp and one very blurry image in the men- tal act. Yet, that this is possible in much higher differences, I have seen in persons who had binocular sight, after one eye had been operated on for cataract and the other was normal. We meet with peculiar idiosyncrasies on this point and only general suggestions, not absolute rules, can be offered. If in myo- pia there be anisometropia of 3 D and vision in each eye good, usually each may take its own correction, and this difference is to be maintained both for near and far. For the near, a working point is to be chosen which will correspond to the capacity of the mus- cles in convergence, and the effort will be to carry it as far away as may be acceptable. One must also bear in mind the power of ac- commodation and by a simple calculation founded upon these two factors the correct working point can be chosen, and the glasses fitted accordingly. Testing the muscular power at six meters when ametropia is corrected and then again for the near will often ex- plain the asthenopia which such persons suffer. It is difficult to give rules to apply to the great variety of cases which are possible, but as the practical difficulties arise at the working distance, it is here that special attention must be given. For instance, a lady who in one eye had E, and in the other M 3 D was made perfectly comfortable by using a plane glass on one eye and — 3D on the other. She wore the glasses constantly for some weeks until she became accustomed to them and afterward she needed them only in reading. Yet, for distance she appreciated the better vision which they conferred. She was about thirty 37ears of age and could easily bring into play the required accommodation. In other cases for the more erroneous eye an incomplete correction must be chosen, because the difference is otherwise too great in the size of the respective images. It can also happen that for the near-point one eye may need a weak convex and the other a concave glass; this is not, however, very common. It is usually unavailing to try to usurp the function of accommodation unless the person is beyond middle life. The degree of accommodative effort to be allowed to the individual is a matter for the exercise of judgment. 1 Report of r>th Internat. Ophth. Congress, p. 165, 1877. 130 DISEASES OF THE EYE. In hypermetropia similar problems present themselves, but not so often do we have large differences in refraction with nearly equal visual acuity, as in myopia. More often do we have great differ- ence in acuity as well as in refraction, and then there is seldom a strong impulse to binocular vision; out of such cases a large con- tingent of converging strabismus is derived. It is frequent for one eye to have, and the other to be free from astigmatism. If vision be thereby impaired in one eye or if asthen- opic symptoms exist, each eye will require its own correction. It is not seldom to find astigmatism different in the respective eyes and a difference in direction of meridians is very common. Some- times a strain is experienced in combining the eyes and such modi- fications may be needed in the axes of the glasses as the comfort of the patient requires. For the patients who have binocular vision for distance and monocular for near, usually exhibiting diverging strabismus in the act of reading, the rule of conduct will be derived from the acuity of the eyes, the degree of divergence, the age, sex and muscular conditions. If we are asked to relieve pain, the method will be to carry the working point farther away by concave glasses adapted to the desired distance, and if this do not suffice, prisms can sometimes be used, or more frequently tenotomy of the muscles can be employed. For patients who use one eye for distance and the other for near, there being extreme difference between them, it is best usually to do nothing. It is not likely that they can acquire binocular vision. It is not rare to meet with such persons, and in some instances the opti- cal difference is not extreme,but there may be an impairment in one or more muscles, or one eye may be astigmatic and the other not. The want of binocular vision is the important circumstance and underlying this is often not only an optical hindrance but a cere- bral inaptitude. I have sometimes spent a long time in vainly try- ing to elicit from such persons evidence of binocular vision, when each eye had adequate acuity and apparently each was capable of fixation upon the desired point. Evidently the images fall upon parts of the retina very nearly correspondent, but there was no cerebral impulse to binocular vision. For such cases usually only one eye is to be corrected. For the class of patients whose ocular discrepancies are so great that they always use only one eye, nothing is to be done save to aid as perfectly as possible the working member in case it needs assist- ance. The other is to be left to purely ornamental functions. ERRORS OF REFRACTION. 131 Incidental Effects of Glasses. It has been previously remarked that glasses worn at the an- terior focal distance (13 mm. in front of the eye) do not alter the visual angle. But nevertheless the linear dimensions of the image are greater with a convex glass, and less with a concave glass. Moreover, if a convex glass be held farther from the eye its magni- fying power is augmented. This is true of distant objects and also obtains for near objects, provided the eye is adapted to a point whose distance is greater than double the focal length of the glass. (Landolt, 1. c, p. 358.) Dropping the glass to the tip of the nose, provided the glass be moderately strong, increases its power. Re- moving concave glasses from the eye diminishes their power. Con- vex glasses limit the range of accommodation—concave glasses in- crease it. The estimation of distances is changed. Convex glasses make objects seem nearer and they alter the sense of relief or per- spective. Concave glasses make objects seem more remote. For these reasons persons are often made dizzy on first wearing glasses or on taking them off. They have difficulty in walking or in reach- ing objects. With very strong convex glasses the field of vision is limited and there is a zone which is determined by the diameter of the glass, where absolutely nothing can be seen (Berlin). This constitutes one of the sources of annoyance to patients wearing cataract glasses. Looking obliquely through strong glasses and especially if they be cylindric, gives distorted images—hence persons wearing them always turn their heads to see an object. Glasses always disturb the relations between convergence and accommoda- tion. When first used for presbyopia, the previous coincidence be- tween these functions in reading gives place to diminished accom- modation with unabated convergence, and the stronger the glasses the greater the disharmony. A myope who uses his dis- tance glasses for reading brings accommodation into unwonted activity with diminished convergence. These perturbations re- quire time for adjustment, and while as a rule, discomfort soon ceases, sometimes it continues until special adjustments are made, which will be considered under the head of asthenopia. CHAPTER Till. BINOCULAR VISION AND ITS DISTURBANCES. Under this head are to be considered such troubles as muscular asthenopia, or insufficiencies of muscles, strabismus, paralysis of muscles, nystagmus, and conjugate deviation. Preliminarily it will be proper to consider the anatomy and physiology of the muscles, and the physiological properties of binocular vision. Anatomy and Physiology of the Ocular Muscles.—Each eye has six muscles. They are combined in pairs, and both eyes are co- ordinated in particular ways. In each eye we have the internal and external, the superior and inferior recti, and the superior and inferior obliqui. All the recti muscles take origin from the apex of the orbit around the foramen opticum, and come forward to be inserted into the sclera in front of the equator oculi, about 7 mm. behind the rim of the cornea, by flat and ribbon-like tendons. The superior oblique or trochlearis also originates at this place; but, inasmuch as it passes over a pulley at the supero-internal angle of the front of the orbit, this becomes its functional place of origin and assimilates its action to that of the inferior oblique, wilich arises from the inner part of the inferior edge of the front of the orbit. Both muscles then pass obliquely outward and backward to wrap around the globe in thin, fan-like tendons, the superior going over the upper part of the globe beneath the superior rectus, and the inferior going over the inferior part of the globe beneath the inferior rectus. The two obliqui hold the globe, as it were, in a sling, which is entirely to the outer side of the optic nerve. The recti, combined in action, retract the globe into the orbit; the obliqui, combined in acton, draw it forward. While the recti in combination have a simple kind of action, the obliqui draw the globe forward and turn the cornea outward. The rectus internus (called by Merkel, rectus medialis) and the rectus externus, move the globe about an axis which is vertical. The rectus superior and the rectus inferior move it about an axis which is transverse to the vertical plane, but which is also inclined so that its outer end is more posterior, making an angle of 67° with the antero-posterior axis of the globe. The axis about which the obliqui rotate the globe passes from before backward and inward on a horizontal; BINOCULAR VISION AND ITS DISTURBANCES. 133 plane at 35° with the antero-posterior axis of the globe (see Fig. 53). The obliqui thus acquire an action which moves the eyeball so that the rim of the cornea turns like a wheel. Taken singly, the muscles act as follows: the rectus internus turns the cornea in- ward on the horizontal plane; the rectus externus turns the cornea outward on the horizontal plane; the rectus superior turns the cornea upward and slightly inward; the rectus inferior turns the cornea downward and slightly inward; the obliquus superior turns the cornea downward and outward, and rotates it from above downward. The obliquus inferior turns the cornea upward and Fig. 53. outward, and rotates it from below upward. In effecting the move- ments of the eyeball all the muscles co-operate: while some pre- dominate, the rest antagonize them to give steadiness to the action. The nerves for the muscles are the sixth or abducens for the rectus externus, the fourth or trochlearis for the superior oblique, and all the rest are supplied by the oculo-motor or third. The blood-vessels are branches of the ophthalmic. The following schedule indicates how the muscles co-operate in effecting certain principal movements. For motion inward, i.e., adduction, the effective muscles are, R. interni and R. sup. and R. inf., antagonized by R. externi and Obi. sup. and Obi. inf. Motion Outward.—Abductors: R. externi, Obliq. sup., and Obliq. inf., antagonized by R. int., R. sup., and R. inf. 134 DISEASES OF THE EYE. Motion Upward.—R. sup., Obi. inf., and when the cornea passes, a given point, the upper fibres of R. int. and R. ext. add to the effect. The antagonists are R. inf. and Obi. sup. Motion Dowmvard.—R. inf. and Obi. sup., while, when the cornea gets below a given point, the lower fibres of R. int. and R. ext. come into play. In motions upon a horizontal axis the R. sup. and inf. incline the top of the vertical meridian respectively inward and outward, which tendency is counterbalanced by the Obi. inferior acting with the R. sup. and by the Obi. sup. acting with the R. inf., which perform the needful rotatory or wheel movement. Taking, now, the concomitant action of the eyes, .we arrange the muscles into groups of adductors, which turn the corneae toward the median plane of the body; and of abductors, which turn the corneae away from the median plane of the body. We also find the muscles pairing off in other combinations in turning the eyes. to the right side and left side respectively, and in the various dia- gonal directions. The eyeballs are capable of accomplishing, with- in a limited range, all possible combinations, but there are certain restrictions which are imposed by the necessity that each must direct its visual line exactly upon the object observed. Hence, for a near object, whether on the median plane or away from it, there must be a slight adduction, as well as an aim suited to the position of the object. For remote objects there will be a degree of abduc- tion, but never to transcend parallelism of the visual lines. We are habitually more concerned with objects below the horizontal plane than with those above it; and in the discussion of the move- ments of the eyes, Meissner has taken an inclination of 15° below the horizon as the primary position; others, however, assume the horizontal plane as the primary position. The degree of mobility of the emmetropic eye in young persons about a vertical axis is from 42° to 51° inward, and from 44° to 49° outward (Donders). In miopia this is much restricted. The horopter is a line which represents the curve along which both eyes can join in sight, and it is formed in this way: as the eyes fix upon a given object far to the left side, and move far to the right at the same inclination of the visual lines, they form a triangle whose apex, as it passes from left to right, forms the horopter curve for this plane. If the movement be in any other plane, vertical or oblique, the horopter will be formed in the same way for that plane. In its simplest form, as explained by Johannes Mueller, it is a circle which passes through the centres of rotation of each eye and through the apex of the point of fixation of the visual lines. This statement is not strictly correct, but will suffice for our purposes. Physiology.—The fundamental and imperative law which gov- BINOCULAR VISION AND ITS DISTURBANCES. 135 erns the muscles of the eyeballs is that the fovea centralis retinse of each eye must be fixed upon the object observed. When this is done, all objects lying in the same horopter will form images upon the respective retinae which will lie at equal distances from the foveas, and will, therefore, be appreciated as single, giving what is called binocular vision. But objects beyond the horopter or inside the horopter, will cast images on parts of the retinae not equally distant from the foveae, and will therefore not be appreciated as single, but create the impression of two objects, giving rise to double vision. The maintenance of correct binocular vision is the necessity which dominates the ocular muscles. If the back of the eyeballs be divided into quadrants by vertical and horizontal planes whose intersection shall be at the fovea centralis, and par- allel to these lines we mark points one-tenth of a millimetre asun- der, and then suppose the two retinae to be superimposed upon each other so that the vertical and horizontal lines shall exactly coincide, the points which we have imagined will of course also coincide. These coincident points, which are equidistant from the centre, are spoken of as correspondent points of the two retinae, and there are of course as many of them as there are percipient points, i.e., bacilli in the two retinae. They are functionally homologated to- gether according to the scheme just imagined. By virtue of this arrangement binocular vision is rendered possible. It follows, of course, that the nasal half of the left retina is linked with the tem- poral half of the right retina; the nasal half of the right retina with the temporal half of the left retina; the superior halves of both retinae are linked together, and the same is true of the inferior halves. This corresponds with the decussation of the optic tracts in the chiasm. Binocular vision is primarily conditioned by the supremacy in acuteness of the fovea centralis above other parts of the retina. But this condition is not the only factor in the function, because experience shows that the brain must possess a certain competency, which sometimes seems to be the quality deficient. For all objects on which we do not fix the foveae, and which consequently are not in the horopter, we have diplopia. If, for in- stance, iu one hand a pin is held at sixteen inches, and in the other another is held at eight inches, and upon the same line, when we look at the distant pin the nearer is seen double, and vice versa. We are not disturbed by double vision of objects on which we are not fixing attention; the mind ignores the impression of the things with which it does not concern itself. This is common experience in shooting, in using the microscope, when the unused eye may be wide open and nothing be known of what it sees. Diplopia follows certain laws. For instance, if the left eye fix on an object and the 136 DISEASES OF THE EYE. axis of the right cross that of the other at a point inside the object —in other words, if there be excessive convergence, the image which in the left falls in the fovea, and whose position in space is projected along the visual line, will in the right eye fall to the inner side of its fovea. Now, the position of the object in space is decided by what the left eye sees, and the right eye has an image which, if it were directed aright, would belong to an object situated to the outer side of its visual line, viz., on its right-hand side. This image is recognized, and is mentally located as if it were on the right side of the object seen by the left eye. In other words, if there be excessive convergence of the visual lines, there Fig. 54.—Convergence with Homonymous Images. will be diplopia with correspondent or homonymous images (see Fig. 54). If, now, while the left eye fixes an object, the visual line of the right diverge, the image will, in the latter, fall to the outer side of its fovea, and will be projected mentally as coming from an object on the left side of the visual axis. Hence, for divergence of the visual axes we have crossed or heteronymous double images (see Fig. 55). If the left eye fix an object, and the right eye be directed downward, the image in the right will fall below its fovea, and be mentally projected above the image seen by the other eye. If the left eye fix and the right eye be turned upward, the image will fall above its fovea, and the projection of the image will be downward below the true place of the object. A candle-flame is usually the BINOCULAR VISION AND ITS DISTURBANCES. 137 object chosen, and a red glass is put before the fixing eye so as readily to distinguish the presence and place of double images. If the visual lines form a wide angle with each other, in the deviating eye the image will fall at a great distance from the fovea, and the result will be that the image is less distinctly perceived because it impinges on a less sensitive part of the retina, and it will also be projected to a greater distance from the true place of the object. For these two reasons, the patient is then less likely to be awrare of double images. It also happens that persons may fix wTith either eye and ignore the image of the other. It is also true that in many persons, and by some it is asserted that in all persons, one eye pre- Fig. 55—Divergence with Crossed (Heteronymous) images. vails over the other, just as one hand is more depended on, than the other. The possession of two eyes confers a quality of sight which is not only more effective than with one only, but is also of a different kind. With two eyes not only does the brain receive a double im- pression, but each eye views an object from a different point and receives a slightly different image. The interpupillary distance varies in adults between 50 and 75 mm. The average may be taken at 64 mm. If an object be within a moderate distance and of suit- able size, say a cube a foot square, ajb 10 feet each eye sees it under a different perspective, and while its form is evident to each alone, the combination of the two images gives what is called the sense of relief or depth. For moderate distance, viz., with the objects on a table, we realize this impression very strongly and unconsciously 138 DISEASES OF THE EYE. form our judgment of the solidity of objects by the dissimilarity of the images portrayed on the respective retinae. We are also aided in this judgment by the projection of objects against parts behind them, and by running the eye along their outlines and from one object to another. The movements which the eyes make are regulated with extreme nicety and are capable of very fine adjust- ments. The acquisition of binocular vision belongs to the first months of life. Young infants roll their eyes about in the most inconsequen- tial fashion, and when their visual vagaries give place to binocular fixation, an important step has been gained in ocular and cerebral development. In some subjects this function is never acquired, in others it may be lost after having been presumably acquired. All cases of permanent strabismus are instances of suppressed, or of lost, or of undeveloped binocular vision. The limitations of binocular vision evidently exclude those motions by which the visual lines are not directed in proper har- mony with each other. That is, one eye may not look up and the other at the same time look down, and the same is true of diagonal movements—they must be harmonious. But in the horizontal, or nearly horizontal plane, the motions of adduction and abduction can be pushed to an extent which shall disharmonize the visual lines. Thus, we may turn the eyes inward so that the visual lines cross by excessive convergence, and we may turn them by abduc- tion so that they fall into divergence. Excessive adduction is pos- sible without artificial aid to a marked degree, excessive abduc- tion is never great, and cannot usually be effected without the aid of prisms. Done by their help, the movement is made to prevent double sight. Thus, if we look at a candle-flame twenty feet away, and put before one eye a prism of five degrees angle, with its base inward, there will for a moment seem to be two candles, but pres- ently they move toward each other and fuse into one. The eye- balls go asunder by a movement of abduction to bring the fovea of one eye inward to the spot on which the prism has deflected the candle-flame. This power of abduction beyond parallelism reaches to a prism of from six degrees to eight degrees in most persons, while adduction for distant objects, say at twenty feet, extends to thirty degrees or to fifty degrees, and by cultivation may go higher. It has already been mentioned (page 19) that with different angles of convergence there will be variations in the possible amount of accommodation, and this is known as the relative accom- modation. It is determined by employing convex and concave spherical glasses for particular angles of convergence. We also have for given amounts of accommodation variable degrees of con- vergence possible, as can be shown by prisms placed with bases BINOCULAR VISION AND ITS DISTURBANCES. 139 inward or outward. In emmetropia the relation of the functions of accommodation and convergence is very different from what we find in myopia and in hyperopia. In myopia with less accommoda- tion, convergence is greater, in hyperopia with more accommoda- tion, convergence is less. We also find great differences among in- dividuals both by natural endowment and from disturbing causes. Not only is an adequate amount of accommodative power essential to comfort in near work, but equally so is a proper proportion of adductive and abductive power. In fact, for all visual functions a correctly adjusted and adequate muscular apparatus is indispensa- ble to comfort and efficiency. We do not yet possess sufficient data to state precisely the necessary physiological conditions in the power of the muscles, but failure in this respect brings on serious functional troubles, which are classed under the name of asthen- opia and under this head we shall discuss the matter. PARALYSIS OF MUSCLES. We may have paralysis, either complete or incomplete (paresis), affecting one muscle or many, in one eye or in both. Symptoms are: 1st. Limitation or irregularity of motion: 2d. False position of the visual axis causing squint when motions in certain directions are attempted. The squint affects at first only one eye, but soon extends to both, by secondary contrac- tion of opposing or associated muscles. For example, if the left rectus externus be paralyzed, not only will the left rectus internus, by reason of the diminished resistance, turn the eye unduly inward, but the rectus internus of the right (opposite) eye will undergo con- traction, and if the left eye look straight forward, the right eye will squint inward. This is because the right rectus internus is associated, in all movements to the left, with the left rectus ex- ternus. Moreover the secondary deviation will exceed the primary; i. e., if the right eye fix on the finger at one foot, the turning inward of the left will be less in angle, than will be that of the right when the left fixes on the finger. In other words, contraction of the right internus exceeds that of the left internus. 3d. Double Images.—This is the usual consequence of disturb- ance of the pre-existing normal co-ordination. In partial paraly- sis some persons have a singular capacity for correcting the diplopia. This power depends upon the instinct for binocular vision, and is called the capacity for fusion. With the same degree of deviation, so far as can be estimated by prisms, the extent over which fusion of double images is achieved will be much greater in some persons than in others. Von Graefe pointed out that, apart from errors of refraction or accommodation, or amblyopia, the capacity for fusion 140 DISEASES OF THE EYE. is far less in cerebral paralysis than in orbital or basilar paralysis. The reason is that binocular vision is essentially a cerebral function. 4th. Incorrect projection of the field of vision.—Because of our habitual reliance on the muscular sense we suppose that the effort we make is followed by the effect to which we are accustomed, but find that our assumption of the position of objects in the field of vision is wrong. For instance, if the left rectus externus is para- lyzed, especially if only partially paralyzed, and the left eye attempt to see an object to the left side, the effort of movement is so much greater than is usually made, that the mind believes the object to lie much farther to the left than it really does, and the hand, in attempting to seize an object or to put the finger on the point of a pencil, strikes to the left side of the true position, i.e., the projection of the field is too far on the side of the action of the muscle. 5th. Dizziness, nausea, and such cerebral symptoms are often present, and may after a time pass away. They are caused by the contusion of images and by the dissociation which is produced be- tween the conscious effort of the muscles and the instability and falsity of the projected field. Objects are made unsteady, the ground does not seem level, going up and down stairs becomes diffi- cult, movements of the hands are ill directed, and from all these phenomena mental confusion and vertigo result, until further expe- rience corrects the judgment. If one eye only be involved, the inclination is to close it. 6th. Another effect is a peculiar attitude which the head as- sumes to obviate double images. The inclination of the head, when this occurs, will be such as to favor the lamed muscle, and will be in its line of action and toward its virtual or anatomical origin. For a paralyzed rectus externus of the left eye, the head will turn on a vertical axis to the left. For a paralyzed rectus su- perior of the left eye, the head will turn on a horizontal axis up- ward and a little to the right. For the obliquus inferior the ten- dency will be the same, both being levators of the cornea, and the head thrown back diminishes the effort in looking upward. Some- times pain is a prominent symptom and very often it is absent. Diagnosis.—We meet in practice with the most complex com- binations, and sometimes it is indeed a puzzle to tell what muscles are at fault. We place most reliance on the character and position of the double images, but to a clear analysis it is necessary to have an intelligent patient with two good eyes each of which shall be quick to observe the image it receives. To complicate the problem, secondary contractions and involuntary compensations by other muscles, may come in to disturb the regular scheme which ought theoretically to be observed in the behavior of the double images, and we are left in the lurch. But in many recent cases we can tell, BINOCULAR VISION AND ITS DISTURBANCES. Ul without analysis of double images, what muscle is affected. The eye refuses to move to the proper degree in the direction of the movement of the impaired muscle, and goes too far to the opposite side; its movements are often partial and jerky. If many muscles are paralyzed, the situation of the globe in the orbit may be altered i.e., exophthalmus may occur. ' To comprehend the value of double images for diagnosis of ocular Paralysis, a few illustrations are employed, which are borrowed Irom Zehender ("Handbuch der Augenheilkunde," 1874, p. 317) and somewhat modified. It has already been stated that two images on the same level, of which the right belongs to the right eye and the left to the left eye, are called homonymous or correspondent. Images on the same level, and of which the right belongs to the left eye and the left to the right eye, are called crossed or heter- onymous. The former implies impaired power of abduction, i.e., the eyes are convergent; and the latter implies impaired power of adduction, that is, the axes are divergent. We have also to study differences in height, i.e., vertical diplopia; and the higher image belongs, as before said, to the eye which points too low, and means impaired power of lifting the cornea, i.e., the levators are at fault- The lower image belongs to the other eye. Again, we are to note whether the images are parallel to each other, and for this we use as a test a long candle or a stick about a foot long. The images may converge or diverge at the top. The cause will lie in deflec- tions of the vertical meridians. We always speak only of the top of the vertical meridian. If now these meridians diverge, the images will incline inward; if they converge, the images will diverge. The obliqui are thus submitted to proof, while to a less degree the same phenomena belong to the recti superiores and recti inferiores. The images are figured as they are seen by the patient. The white candle denotes the image seen by the sound eye, the dark candle that seen by the paralyzed eye. (In practice it is better to put a red glass over the eye which fixes, and which is generally the sound eye, so that the image seen indirectly and by the paralyzed eye may be relatively more distinct. This sugges- tion is not observed in the diagrams.) It is supposed that the candle is carried to the several positions represented across the field and the shaded part of the diagram indicates the region in which double images arise—viz., right or left, above or below. Fig. 56 shows the double images in, 1st, paralysis of the rectus externus oculi sinistri, and likewise those in, 2d, paralysis of the rectus internus oculi dextri—the one being the counterpart of the other, except that in the former the images are homonymous, in the latter they are crossed. If the same figure were looked at 142 DISEASES OF THE EYE. through the paper from its back side, or were looked at as reflected from a mirror, it would be reversed, and then would represent, as seen in Fig. 57, 3d, paralysis of the rectus externus oculi dextri, or 4th, paralysis of the rectus internus oculi sinistri. In the third case the images are homonymous; in the fourth, they are crossed. The images viewed on the horizon are vertical and parallel, while Fig. 56. Fig. 57. the eyes turned up cause them to diverge at the top, and, if turned down, to converge at the top to a slight and physiological degree. In looking upward the rectus superior predominates and causes the vertical meridian to converge—hence, divergence of the images; and vice versa, in looking down, the action of the rectus inferior causes the images to converge. Fig. 58. Fig. 59. Fig. 58 gives the situation and relation of the images in, 5th, paralysis of the rectus superior oculi sinistri, and its reverse in Fig. 59 exhibits, 6th, paralysis of the rectus superior oculi dextri. It is noticed that difference in height (Fig. 58) increases toward the left, and obliquity increases toward the right, the reverse occurring in Fig. 59. In both cases the images are crossed. In Fig. 60 we have the images seen in 7th, paralysis of the rectus inferior oculi sinistri, and reversed in Fig. 61 of, 8th, paralysis of rectus inferior oculi dextri. BINOCULAR VISION AND ITS DISTURBANCES. 143 In this figure again the images are crossed, and they diverge more widely toward the side of the affected muscle, and the obliquity diminishes toward the same side. The figures give the diplopia only in the extreme upper and lower parts of the field, where the difference in height is greatest; on the median line it will be less, and at the opposite part of the field there will be single vision. Fig. 60. Fig. 61. *In Fig. 62 are represented the double images found in, 9th, para- lysis of the obliquus superior oculi sinistri, where they are homony- mous; and if reversed, as in Fig. 63, we have, 10th, paralysis of obliquus superior oculi dextri. In these cases the notable thing is that, besides being homony- mous, there is difference in height and remarkable obliquity. Fig. 62. Fig. 63. The vertical separation increases on the side of the sound eye, while the obliquity increases on the side of the impaired eye. Paralysis of the inferior oblique, which is rare, gives double images in the upper part of the field, and with difference in height as well as lateral displacement, the images being crossed, which is the fact in the case of the writer who has this affection, but by most author. ities they are called homonymous (see Trans. Am. Oph. Soc, 1879, p. 551) and diverging at the top. 144 DISEASES OF THE EYE. Not infrequently one image seems to be farther removed than the other. To aid a patient in describing what he sees, it will be well to let him have a stick in each hand, and with them to imitate the position of the images. To determine which is the true and which is the false image is generally easj*, because the patient will naturally fix with the sound eye. We shall also be guided by other symptoms in deciding upon the faulty eye. By observing in what direction the least displacement occurs and the line in which the images separate most widely, the erroneous eye will soon be detected. Moreover, while a patient fixes on an object, if the screen be quickly shifted from one eye to the other, the eye which does not remain steady, but makes a slight movement of adjustment, is the affected one. Patients can by their own sensa- tions often tell which is the injured eye. For isolated paralyses and for some cases of multiple paralysis there will be no great difficulty in deciding which are the faulty muscles. When all the twigs of the third nerve are thrown out of function, we readily recognize it, because only the rectus externus and superior oblique remain intact, and the pupil is moderately dilated and there is ptosis. There will often be slight exophthal- mus. We also sometimes have all the muscles of one eye paralyzed, and it then stands immovably at the middle of the orbit and the upper lid drops, while the globe has a tendency to exophthalmus. We also have various combinations which are sometimes impossible to unravel, and compensatory effects are sometimes added to the original complications. The above schemes of double images will often fail to be realized and are simply guides for investigation. Having discussed the ocular phenomena and ascertained what muscles are at fault, we are confronted with another problem in diagnosis, viz., where the lesion is situated: whether in the orbit or within the cranium. The sphenoidal fissure is a favorite site of paralytic lesions. This opening, closed by a dense fibrous mem- brane, is chiefly occupied by the cavernous sinus, on whose wall at its medial side is a fibrous canal by which the nerves enter in a bundle, viz., the three motor and the ophthalmic branch of the trigeminus, while the ophthalmic vein passes out below the oculo- motorius. An intra-cranial lesion may affect the nerves at the base of the skull, or within the cerebrum. We find the trunks as they enter the brain subdivided into fasciculi or rootlets, which ter- minate in nuclei located in the mid-brain, and from these nuclei connecting fibres proceed to the cortex. We thus subdivide intra- cranial paralyses into, 1, basal; 2, fascicular; 3, nuclear; 4, sub- cortical; and. 5, cortical. We must have a critical knowledge of anatomy to be qualified to understand or investigate the intricate problems of pathology which now challenge our study. BINOCULAR VISION AND ITS DISTURBANCES. 145 Leaving the sphenoidal fissure, the motor nerves pass backward alongside the sella turcica, and we find them ranged in the follow- ing order from the median line outward: The 3d, the 4th, the 6th, and to the outside, the trunk of the 5th, with the ganglion of Gasser lying on the anterior face of the pars petrosa. It would be unsuitable to enter deeply into details in a treatise on ophthal- mology, but we want at least an approximate knowledge of the place of the lesion if it be located within the cranium. We therefore present the follow- ing anatomical summary—relying largely on illustrations. A transverse section through the frontal bone just behind the apices of the orbits discloses an instructive view of the cranial cavity, as seen in Fig. 64 from Henle. It gives a section of the cavernous sinuses and of the internal carotid arteries; the tentorium being preserved, we are reminded of the im- portance of the dura mater, both in supporting the oc- cipital lobes, in determin- ing the cause of exuda- tions and abscesses, and also its influence, when in- flamed, upon the nerves and brain tissue because of its large enveloping surface and penetrating septa. We see also the large cerebral sinuses. Another impor- tant elementary fact of which we may be reminded is the arterial supply of the base of the brain. The vertebrals unite at the pos- terior edge of the pons to form the basilar artery, and this bifurcates upon the crura cerebri (pedun- cles) to enclose within the circle of Willis the corpora albican tia (mammillaria) , , . . , . Fig. 64.—1, Sphenoid sinuses; 2, internal carotid artery; 3, ana tlie optic Ciliasm, inferior maxillary nerve; 4, tentorium cerebelli; 5, falx cerebri. alongside of which come up the internal carotid.s after their sinuous twisting; and in front of the chiasm the circle of Willis is completed by the anterior communicating artery. Leaving out of view the hemispheres we limit our study chiefly to the parts about and caudad the third ventricle. A ventral view (see Fig. 65) displays the cranial nerves and the various organs along the median line as far as the decussation of the pyramids. It will be remembered that the pons Varolii lies upon the basilar process and that along its median line is a furrow for the basilar artery. Fig. 66, from which parts have been excised, may be placed alongside Fig. 65 to complete the mental picture. We may simply call attention to the optic tracts which part from each other at the chiasm and pass laterally and caudad to twine around the crura cerebri and lose themselves in the brain substance. We note the two geniculate bodies i 10 146 DISEASES OF THE EYE. and e, of which only the external (lateral) has any connection with vision (Fig. 65). At the heel of the optic thalamus, Th, is a nidus of gray matter called the pulvinar (Fig. 66), which, like its neighbor the external genicu- late body, is a primary visual ganglion. The cross X between the crura (Fig. 65) denotes the pos- terior perforated space, a lamina of gray matter pierced by small arteries, which is the floor of the third ventricle. In Fig. 67 from Henle, we have an alcoholic speci- men, showing the third ventricle and the beginning of the crura: the section is presented a little obliquely and the tractus opticus II' is turned aside. The crus cerebri appears near the optic thalamus and is cut off just above the pons. In the crus we distinguish the ven- tral portion B, basis or crusta, and the dorsal por- tion T or tegmentum. Be- tween is a thin ganglionic layer, Sn, the substantia nigra, or ganglion of Soem- mering. In the basis of the crus are gathered the fibres forming the internal capsule which have come down from the cortex, and which are chiefly motor. In the teg- mentum the fibres are most" ly sensory, besides nuclei and gray matter. It in- cludes very dissimilar struc- Fig. 65.—Base of the Brain and Cranial Nerves, Pons and Medulla. I to XII, The cranial nerves; Th, optic thalamus; h, pituitary body; tc, tuber cinereum; a, corpora albicantia . (mammillaria); P, pes peduneuli; i, internal geniculate tures, and extends ironi tlie body; e, external geniculate body; PV, pons Varolii; pa, anterior pyramid of medulla; t>, olive; d, decussation of an- terior pyramids; ca. anterior column of spinal cord; cl, lateral column of spinal cord; Ce, cerebellum; fl, flocculus of cerebellum; X, locus perforatus posticus; + (on the left side), ganglion of Gasser; + (on the right side), motor root of tri- geminus. thalamus to the crossing of the pyramids. It is merely a convenient topographical term, viz., the roof of the basis of the crus. Dorsad to the tegmentum is the canal of Sylvius, and the roof of the latter is made by the corpora quadrigemina and the velum medullare anticum (valve of Vieussens). The substantia nigra, and cephalad to it the corpus subthal- amicum (Luy's body), and caudad the red nucleus of the tegmentum are a series of ganglia located between the crusta and the tegmentum, to which we merely allude. The crura, as seen in Fig. 65, diverge from the pons to the thalami optici, have a slightly fluted and twisted appearance, and enclose a triangular area called the posterior perforated space. At the apex of this triangle we have the emergence of the third nerves. BINOCULAR VISION AND ITS DISTURBANCES. 147 Our business is chiefly with the ocular nerves, and it would be natural to enter at once upon a description of their course andrelations in the medulla. We cannot appreciate their characteristics and the events which may happen when lesions attack them, without acquaintance with their environment and the functions, so far as known, of the organs amid which they are placed. We shall therefore not go astray if we sketch broadly the features of the medulla and the pons. F< >r an accurate study see the article on '' Brain: histology," by Spitzka, •' Reference Handbook Med. Sciences" (Wm. Wood & Co., 1887). The translations of Obersteinerl and Edinger2 will be freely used. Dr. M. A. Starr has treated the subject in a most lucid manner in an article3 in the li Reference Handbook of the Medical Sciences." Dr. Starr traces the several tracts which go through the medulla and enumerates four: 1st, The tracts connecting the cerebrum and cerebellum. They are the outer and inner thirds of each pes, and they are to a large extent lost upon the masses of gray matter which are intermingled with them and with the transverse fibres of the pons. They also make up the superior P Ca Fig. 66.—Base of the Brain to show the Emergence of the Optic Nerves. The cerebral hemi- spheres have been removed to show the posterior portion of the optic thalamus. The peduncles have been divided behind the corpora quadrigemhia. Cgm, Corpus geniculatum mediale; Cgl, corpus geniculatum laterale; P, pulvinar of the thalamus; Ch, chiasma nervorum opticorum; Cq, corpora quadrigemina; Aq, aqueductus Sylvii; Ccb, pedunculus cerebri; Cc, corpora can- dicantia (mammillaria); Tc, tuber cinereum; .7, infundibulum; 1, tractus olfactorius separating into its middle and lateral roots; Spa, substantia perforata anterior. and middle peduncles of the cerebellum. The inferior peduncle of the cerebellum is continuous with the columns of the cord. We also have in the pons, fibres passing from one hemisphere of the cerebellum to the other. The longitudinal fibres grow less numerous as Ave proceed caudad, being reduced to about one-fifth in volume. Lesions in the superior and middle peduncles of the cerebellum are not easily recognized, giving rise, like those due to cerebellar disturbance, to loss of equilibrium. In the 2d division we have the middle third of the fibres of the pes or crusta which compose the great motor tracts coming from the motor areas of the cortex. Those for the arm and leg cross at the pyramids at the lower end of the medulla and form the lateral columns of the cord; that is, about •"Central Nervous Organs," Phil., 1890. ■ '' Structure of the Central Nervous System," Phil., 1891. s " Pons Varolii and Medulla Oblongata, Diagnosis of Local Lesions in," vol. v., p. 773. 148 DISEASES OF THE EYE. four-fifths of the fibres decussate, and the remainder continue straight down the anterior columns. Besides the above fibres we have in the pons special nuclei for the facial (seventh) and hypoglossal (twelfth) nerves, and the fibres from them also decussate, but at higher levels than the pyramids. Hence various combinations of paralysis of face, tongue, and extremities are possible according to the place of lesion. The figures from Starr illustrate these possibilities (Figs. 68, 69). The 3d set of fibres is the tract for muscular sense, called the fillet or lemniscus, and when in the medulla called interolivary tract. It conveys sensation upward, and for this reason we trace it in this direction. The columns of Coll and Burdach in the dorsal surface of the spinal cord ter- minate at the nuclei gracilis and cuneatus. The fillet starts from these nuclei, and as it goes cephalad the two bands decussate at a point above the pyramids (sensory crossing of Wernicke) and enter the pons. It becomes ribbon-like, and later assumes an L shape, lying beneath the deep transverse bundles of the pons, in front of the formatio reticularis. In the tegmentum it lies mainly to the outer side and reaches the cortex, passing through the caudal part of the internal capsule. 4th. The sensory tract, which transmits sensations of touch, temperature, Fig. 67 (Henle).—Right Half of Brain turned obliquely upward—the peduncle T divided near its entrance into the thalamus Tho; II', the optic tract turned back. I, Olfactory nerve; CcV2, knee of the corpus callosum; SI, septum lucidum; Coa, Com, commissura anterior and media; Cn, conarium (pineal gland); Lq, lamina of corpora quadrigemina; Ccl*, splenium of the corpus cal- losum; Sn, substantia nigra; B, basis; Cca, peduncle of the corpora mammillaria. and pain through the medulla and pons, is in the formatio reticularis. This portion of the medulla and pons lies just beneath the gray matter of the floor of the fourth ventricle, behind the tracts hitherto described. It is made up of nerve-fibres passing in three directions : a, transversely, the commis- sural fibres of the cranial nerve nuclei; b, from the nuclei ventrad, the fibres of the cranial nerve-roots and arciform fibres; e, longitudinally, the sensory tract. The longitudinal fibres can be traced from the gray matter and various columns of the spinal cord, through the formatio reticularis to its upper level in the tegmentum of the crus, whence they issue to enter the posterior part of the internal capsule. In the medulla the formatio reticu- laris of each side is divided into two parts by the line of exit of the nerve-roots of the twelfth. The inner part, near the median line, con- tains the continuation of the anterior and anterolateral columns of the spinal cord, and the interolivary tract or lemniscus already described. The outer part contains the sensory tract now under consideration. In the inner two-thirds of this outer part the fibres pass which convey impressions of BINOCULAR VISION AND ITS DISTURBANCES. 149 touch, temperature, and pain from the opposite half of the trunk and limbs in the outer third of this part is found a column of peculiar structure re- sembling the substantia gelatinosa of the posterior horn of the spinal cord and in this column terminate the fibres of the sensory part of the trigeminal nerve which turn downward after entering the pons Varolii, and ter- minate at different levels in the pons and medulla (see Fig. 69). Thus the outer position of the formatio reticularis contains the sensory tract from the face of the same side. It is evident from the diagram that a lesion which involves one-half of the formatio reticularis in the pons and medulla will produce an alternating anaesthesia, i.e., loss of sensation on one side of the body and on the other side of the face and head (lesion at B, Fig. 69). Alternating anaesthesia is as characteristic a symptom of lesions of the formatio reticularis of the pons and medulla, as alternating pa- ralysis is of lesions in the motor tract of the pons. In the upper part of the pons the sensory tract from the face crosses the median line, and hence ;yjr nucuvs. WHERve: Y nerve Fig. 68. Fig. Fig. 68.—Lesion of Pons, with Alternating Motor Paralysis. Lesion at A causes hemiplegia of side opposite to lesion; lesion at B causes alternating paralysis, viz., body on right side, face on left side; lesion at C causes paralysis of tongue on side of lesion and of extremities of opposite side; lesion at D causes paralysis of extremities of opposite side; lesion at E causes paralysis of extremities of both sides. Fig. 69 —Lesion of Pons, with Alternating Anaesthesia. The course of the sensory tract in pons and medulla. A, Lesion in tegmentum cruris cerebri, or upper quarter of pons, producing hemian- sesthesia of the opposite side; B, lesion in formatio reticularis of pons or medulla, producing alter- nating anaesthesia. a lesion in the formatio reticularis in the upper third of the pons, or in the crus cerebri, will produce a unilateral anaesthesia (lesion at A, Fig. 69). A lesion involving both halves of the formatio reticularis will produce bilateral sensory symptoms. It is evident that a lesion of any extent, either in the pons or medulla, will inevitably destroy one or more of these four tracts, and consequently will produce serious symptoms of wide extent and of considerable diversity (Starr). If now we make a section normal to the axis of the pons through the width of the anterior corpora quadrigemina (Fig. 70), we shall have a view 150 DISEASES OF THE EYE. of the rootlets of the third nerve as ttiey gather together to form Its stem. We see that they traverse and surround a rounded mass of reticular sub- stance called the red nucleus of the tegmentum. This body extends cepha- lad to the optic thalamus and receives fibres from the fasciculus retroflexus (Meynert's bundle), and also connects with the cerebellum by its superior peduncle. It has nothing to do with the oculo-motor nerve. Below and laterally is the substantia nigra of Soemmering, into which run fibres from the lenticular nucleus (see Fig. 67), and below that the crusta of the pes. On the median line at Jf is a decussation of fibres, spoken of above, named after Meynert, and below this another decussation named after Forel, F. At Fig. 70.—Cross Section at Caudal Edge of Ant. Corp. Quad. Tho, Thalamus opticus; Cgm, corpus geniculatum mediale; Cgl, corpus geniculatum laterale; II, tractus opticus; Pp, pes pedun cuh; SnS, substantia nigra; Ntg, red nucleus of the tegmentum; 727, root fibres of the oculo-mo- tor nerve; Pcm, pedunculus corporis mammillaris; M, Meynert's fountain-like tegmentum crossing; Lm, lemniscus; Fcop, fibres in formatio reticularis which have come from the posterior commis- sure: Vd, descending root of trigeminus; Aq, aqueduct; Ftp, fasciculus longitudinalis posterior; Brqp, braehium from corpora quadrigemina; Nqa, nucleus of anterior corpora quadrigemina; Sqt, sulcus transversus; Sqs, sulcus longitudinalis; F, Forel's ventral decussation of tegmentum. Lm is a portion of the fillet, the tract for muscular sensation, and mesial to it Fcop indicates a spot where fibres stream from the posterior commissure in the roof of the aqueduct into the tegmentum. This locality is made up of fine arcuate fibres giving it the name already used of formatio reticularis tegmenti, area reticularis, etc. At the extreme lateral side of the figure we have a portion of the thalamus and of the two geniculate bodies Cgl, Cgm. and below is the optic tract. Below at the middle of the figure in the sulcus is a bundle of fibres coming down from the mammillary bodies. Mesially next the middle geniculate body is a section of the posterior commissure or braehium conjunctivae of the corpora quadrigemina, and at Nqa is its nucleus designated by Qa. Cephalad of the region displayed in this section are other ganglionic masses, the corpus subthalamicum (nucleus of Luys, etc.), the ganglion habenulaa, the mammillary bodies, and these structures must be left out of consideration, as well as various bundles of fibres which have been isolated and described. Lastly, it must be stated that the walls of the third ventricle, of the aqueduct and the floor of the fourth ventricle are covered by a layer of gray matter, which has important functions. It is conjectured that this substance in the third ventricle has influence upon sleep; we know that lesion of the floor of the fourth ventricle is a cause of diabetes mellitus. The respiratory centre in the vagus nucleus will not be forgotten. BINOCULAR VISION AND ITS DISTURBANCES. 151 The remarkable complexity of this region renders its pathological phe- nomena exceedingly difficult to analyze. Dismissing the parts which are only accessory to the main object of the Yl W JtuclAud ■■ A/uclFa-cial present study, we take up the nuclear origin of the ocular and associated nerves. We here introduce a composite (Fig. 71) from Edinger to show on a sagittal 152 DISEASES OF THE EYE. section the relations of the parts under consideration. The black lines de- note motor structures, the red lines sensitive structures. The lettering ex- plains the figure, and we shall frequently refer to it. Another cut presenting the parts in face wiU serve to aid in locating the relations of the origins of the nerves (Knies). 3d Ventricle...... Aqueduct. Sylvii ---.._ Anterior and")""' "" " \ Ccrp, quad Posterior X........___w__ Pedunc. Cerebri 4th Ventricle Accommod. Sphincter iridis III Central Canal of Cord _. Fig. 72. The third nerve, oculo-motorius, turns inward around the crus cerebri, approaching its fellow of the opposite side, and enters the brain at the ceph- alic and ventral edge of the pons (see Fig. 71). The fourth nerve climbs the outer side of the crus and enters the brain at the cephalic and dorsal edge of the pons. It is slender and exposed for a long course. The sixth follows down the basilar process and disappears at the caudal and ventral edge of the pons. The nearness of the oculo-motorii to each other at the posterior per- forated space makes them liable to be both implicated in a single lesion, such as a tumor or hemorrhage (see Fig. 65). We trace the third nerve into the brain, and we find it terminate in a group of nuclei beneath the aqueduct of Sylvius lying upon the fibres of the posterior longitudinal bundle (see Fig. 71). These nuclei have been most successfully studied and we possess a probably accurate knowledge of their individual functions. Kahler and Pick,1 and afterward Starr,2 arranged them in the order of their function, and the recent studies of Perlia3 and Siemerling4 have only slightly modified their order. The nuclei of the two oculo-motor nerves combine to form an almost regular tri- 1 Zeitschrift fur Heilkunde, 1881. '2 Journal of Nervous and Mental Diseases, May, 1888. 3 Graefe's Archives Ophth., xxxv., iv., 287, 1889. 4 Archiv f. Psychiatrie und Nerven krankheiten, xxii., Supple, heft, 1891. BINOCULAR VISION AND ITS DISTURBANCES. 153 angle of broad base, its sagittal length about 10 mm., and it lies between the caudal portion of the third ventricle above the mammillary bodies and the region of the posterior corpora quadrigemina, occupying the whole of the floor of the iter e tertio ad quartern ventriculum (aqueduct). There are, according to Perlia, seven clusters which can be more or less perfectly isolated and arranged in pairs, and there is one on the median line common to each side, making eight nuclei for each third nerve (see Fig. 73). Of the paired nuclei, two in front are separated distinctly from those behind, which are more closely approximated. Of the caudal pairs two are above (dor- sal) and two below (ventral). The most caudal, which is also ventral comes 1 Sphincter iridis. 4 Rect. sup. 5 Obliq. inf. Fig. 73. 2 Levator palp. sup. 3 Mus. ciliaris. 6 Rect. intern. 7 Rect. inf. 9 Trochlearis. O be 2 Levator palp. sup. 3 Mus. ciliaris. 6 Rectus internus. 7 Rectum inf. 9 Trochlearis. Fig. 74. 1 Sphincter iridis. 4 Rect. sup. 5 Obliq. inf. close to the nucleus for the trochlearis. The figure from Perlia (72) is num- bered according to the scheme of Knies,1 and the nuclei may be placed in two rows, of which the dorsal are also lateral, viz., 4 and 5. See also cut of same nuclei from Edinger (Fig. 74). This arrangement differs from that of Kahler and Pick2 (see Starr, 1. c.) in placing the levator palp, nearer the median line and cephalad, and places on the median line the nucleus for convergence. The close vicinity of the levator palp, to the rect. superior is not disturbed, a relation abundantly confirmed by clinical experience. Other parts remain the same. The dorsal nuclei are for the rectus superior and the obliquus inferior. The ventral are for the rectus internus and rectus inferior. It is seen that a very natural collocation exists; 1 Archiv f. Augenheilkunde, xxiii., 44, 1891. sZeitschrift fur Heilkunde, 1881. 154 DISEASES OF THE EYE. that the group of adductors, R. int. (6), R. inf. (7) (both ventral), and R. sup. (4) dorsal and overlapping, lie closely grouped and in contact with the com- mon nucleus (8) for convergence. The levators, R. sup. (4) obliq. inf. (5) and the depressors, R. inf. (7) and trochlearis (9) also lie in series. The muscles for the pupil and for accommodation are together, although a little apart from others, while accommodation and convergence take their closely related positions. Decussation of fibres of the nuclei had been noted by Gudden and others, but, Knies happily points out that the more accurate description of Perlia authorizes us to say that the decussating fibres belong to the nucleus for the obi. inferior (5), and put it in harmony with the nucleus of the trochlearis of the same side whose roots have long been known to cross in the velum medullare anterius (valve of Vieussens). Therefore the recti muscles of the right side get their impulse from the nuclei of the same side of the brain, but the obliqui of the right side take their impulse from the opposite side of the brain, and vice versa. Hence, if a lesion involve all the nuclei of the right half of the brain, the paralyzed muscles will be all the recti, the pupil and accommodation on the same side, but the inferior ob- lique of the opposite side. The trochlearis of the other side might or might not be paralyzed. Something further must be said respecting the connecting fibres. The nuclei are situated, as has been said, upon the posterior longitudinal bundle (see Fig. 71, Edinger), and Perlia (1. c, p. 302) signalizes a tangle of fibres which hangs like a web above the whole group and spins out laterally into the nuclei. Near the raphe they incline ventrally beneath the pos- terior longitudinal bundle and turn cephalad in curves. Approaching the third ventricle they bend around the peduncles and are lost in the sub- stantia reticularis. We thus have two sets of connecting fibres, one sagit- tal and coarse (Spitzka) and a finer set coming more or less vertically from the gray matter of the wall of the fourth ventricle. Perlia also calls attention to offshoots from the interpeduncular transverse commissure of Hall and Gudden, leaving the optic tract in the anterior corpora quadrigemina and descending to wind around the outer surface of the crus to enter the base of the brain a little in front of the oculo-motor nerve. One branch of this bundle goes to the nuclei of the anterior root of the 3d nerve, and another branch traverses the middle of the nuclear group to gain the nuclei of the trochlearis (1. c, p. 307). These connections establish relations between the optic tract, the tubercula quadrigemina anteriora, and the nu- clei of the ocular muscles. Such an arrangement explains Graefe's case (1856) in which, with paralysis of all the extrinsic muscles of the globe, the reaction of the pupil to light was destroyed, but its reaction to convergence and ac- commodation remained. The recognition of a special centre for convergence (8) and the existence of longitudinal fibres on the floor of the fourth ventricle which connect the nuclei of the third (Edinger, Spitzka), make it clear why contraction of the pupil may fail to occur under feeble stimulus of impaired optic nerve fibres, but may occur with convergence ; and that convergence is a more efficient agent than accommodation, as can be experimentally proved. Just behind the oculo-motor nest of nuclei is found that for the troch- learis. Its root fibres unlike those of the third mount upward, enter the velum medullare (valve of Vieussens) and decussate almost if not quite completely, so that the nucleus for the right superior oblique muscle lies on the left side of the median plane and vice versa. We thus have the origin of each obliqae muscle, both inferior and superior, located across the median line of the eye designated—a singular harmony. BINOCULAR VISION AND ITS DISTURBANCES. 155 The nucleus of the sixth, the abducens, lies beneath the floor of the ventricle at about its middle, and the fibres go down through the body of the pons to appear at its caudal edge (see Figs. 65 and 71). Between the abducens nucleus and that for the internal rectus is a connecting bundle of fibres which Siemerling claims has not been anatomically demonstrated, but which on clinical evidence indisputably exists. Besides the relations now described we take note of another important fact, viz., that the abducens nucleus is included in a bend of the fibres of the facial nerve at the point called the knee (Fig. 71). Indeed by some the facial is said to have a nucleus of origin at or near the nucleus of the abdu- cens, while Spitzka says it receives an accession of fibres from the posterior fasciculus (the longitudinal bundle). The place of this remarkable relation- ship is denoted by a slight bulge on the floor of the ventricle, the eminentia teres. At this point originate those fibres of the facial which supply the or- bicularis and frontal muscles, and we are enabled to understand how some- times only the lower facial branches may be injured, as happens in bulbar palsy, because only the lower (caudad) nucleus is involved—while the orbicu- laris is spared. On the other hand Birdsall1 observed ophthalmoplegia ex- terna in which the excitability of the orbicularis and frontal muscles was im- paired. This tallies with the remark of Spitzka as to the accession of fibres "aberrant from the oculo-motor nidus" to the facial from the posterior fasci- culus, and with Mendel's2 experiments, Avho located the ocular facial nucleus in the posterior part of the third nucleus; in this he coincides with Bech- terew, 1883. This interesting relation teaches us the impulse to the act of winking. We must also bear in mind the sensory reflex for the action of the orbicularis, as shown in winking and blepharospasm, which brings us to the fifth or trigeminus. The fifth nerve is both motor and sensory, but we are chiefly interested in its sensory portion. Its nuclear origin is very extensive, particularly in the sensory portion, and its origins are both widely separated and remote from the roots of other nerves ; the nearest being those of the fourth and sixth. Tracing it from the surface of the pons, which it enters at about its middle and remote from the median line, its sensory root passes backward and inward to some small groups of cells lying beneath the floor of the fourth ventricle known as the middle nucleus. The majority of the fibres, however, turn downward through the pons and medulla under the name of the as- cending root, being described as starting from all levels above the cervical spinal cord as low as the second cervical nerve, and terminating in a long column of gray matter which is continuous with the gelatinous substance of the posterior horn (the gray tubercle of Rolando). Another portion of the sensory root (descending) may be traced upward from the level of the mid- dle nucleus as high as the upper part of the corpora quadrigemina, where they arise from large round nerve-cells. They lie external to the aqueduct of Sylvius and are arranged in the form of a crescent (see Fig. 71). These fibres may be implicated in affections involving the ocular nuclei. The majority of the fibres of the motor root arise from a nucleus near to and inside of the middle sensory nucleus (see Figs. 71 and 72). Spitzka gives six roots to the trigeminus, while Magnus indicates four.3 Following the special purposes of an ophthalmic inquiry, we touch inci- 1 Journal of Nervous and Mental Disease, Feb., 1887, p. 65. 2 Berlin. Klin. Wochen., 1887, p. 913. 3 See Edinger, p. 209, Am. Ed., also Obersteiner, p. 292, Am. Ed. 156 DISEASES OF THE EYE. dentally on the close relations of the facial (7th) and thehypoglossus (12th) be- cause their root fibres lie close together under the floor of the fourth ventricle (see Fig. 71). The principal nucleus of the twelfth lies far down the medulla and its origin is extensively distributed (see Fig. 72). It is usually with pa- ralysis of the lower face that deflection of the tongue is linked and then the lesion will be low down; but it may concur with impairment of the orbicu- laris and then the lesion is high up near the eminentia teres and may com- promise eye muscles, abducens, etc. Some singular cases in which the open- Fig. 75. ingof the mouth causes movement of the upper lid1 are accounted for by assuming an abnormal connection between the facial nucleus, the upper nu- cleus of the hypoglossus, and the motor oculi at the spot referred to. 1 See Michel, Jahresbericht, 1892, p. 354—and Hubbel, Arch, of Ophthal. BINOCULAR VISION AND ITS DISTURBANCES. 157 We may dwell no longer upon the pons and medulla, but now state what is held as to the cortical representation of the ocular motor nerves. On this point our knowledge is not precise. Experimenters have reached different conclusions. Mills1 gives a minute diagram of the separate subdivisions of the motor region founded chiefly on the conclusions of Horsley and Schaefer. They decide upon the second frontal convolution as the area for movement of the head and eyes. Ferrier concurs with this view and also adds the angular gyrus and superior temporo-sphenoidal convolution as capable of the same effect. For details see Mills, 1. c, p. 236. Others quoted by Knies2 fix upon the lower part of the parietal lobe, also upon the visual area of the occipital lobe, etc. It is clear that irritation of a large portion of the cortex will excite ocular movements. And this is what we might expect, knowing that noises, a touch, a flash of light, will make us turn our eyes to the ex- pected point. It is to be noted that all cor- tical stimulation gives rise to conjugate or associate movements of the eyes, i.e., to binocular visual direction, never to isolated movements of one eye. For the levator palpebral a special area is claimed at the lower part of the parietal convolution, near the upper facial and the hypoglossal, and that it controls the opposite eye. But we cannot set apart any definite area of the cortex as dominating eye movements as we can for the hand or thumb, etc. Knies (1. c.) very ably discusses all the known facts and concludes that we must assign to the visual area the directing power for all intentional or voluntary movements of the eyes, while to the nuclei come fibres from almost all parts of the cortex, exciting purely reflex movements. Fig. 75 (Starr) gives the latest arrangement in condensed form. Sub-cortical lesions are, of course, possible, and we have somewhat more definite knowledge about them. In Forster's diagram (Fig. 76), giving a horizontal section just dorsad of the third ventricle, we have a spot cephalad the knee of the internal capsule marked eye, at which lesions will affect eye movements. Again OP marks the place where the optic radiation comes in from the occipital lobe ; here is the spot where hemianopsia may be produced. Coming farther down the tract, in the peduncle we come upon a spot where a lesion will cause hemiplegia of the opposite side, and paralysis of the oculo- motor nerve of the side of the lesion. This point is one to be specially noted. If the oculo-motor paralysis does not include the pupil and the ciliary muscle, the lesion will be in the peduncle and rather small. If these nuclei are included, the lesion will be at the base, or so large as to affect the third ventricle, where the pupillary and ciliary nuclei are found One case is given where right hemiplegia, paralysis of face and tongue, and total paralysis of Fig. 76. '" Cerebral Localization," Trans. Congress Am. Physicians and Surgeons, vol. i., p. 219, 1888. 2Archiv f. Augenheilkunde, xxiii., 1, 22, 1891. DISEASES OF THE EYE. the left oculo-motor occurred from a small lesion at the very end of the pe- duncle (Mauthner1). Diagnosis.—By what has been set forth in anatomy and physiology much has been done to aid in making- a clinical diag- nosis, and we may now consider the question from this stand- point. Orbital paralysis will be fairly assumed in the presence of tumors, injuries, abscesses, or periostitis in the orbit. The same is true of tenonitis and hemorrhage. The eyeball may, of course, be prominent, and pain in pushing it back is an important sign. Should the inferior oblique escape while all other muscles are paralyzed, this is explained by its anatomi- cal origin. On the other hand, paralysis of the inferior oblique with paralysis of the sphincter pupillEe and of accommodation is explained by a lesion of the motor root of the ophthalmic ganglion (radix brevis), which supplies the parts enumerated. Congenital absence of muscles has been reported; while most con- genital paralyses are nuclear. A peripheral or rheumatic paraly- sis is difficult to prove, yet we cannot always make a better diag- nosis. We have already spoken of lesions at the sphenoidal fissure which may impair all the nerves here passing and may even in- volve both eyes. Symmetrical paralyzing lesions in both orbits are recorded. Graefe, 1864, reported schirrus in each orbit, Scott2 grummata in each orbit of a child five years old. How the optic nerve may escape when the nerves at the sphenoidal fissure are perhaps all implicated is explained by the separation between their respective foramina, the former above the clinoid process of the sphenoidal wing, the latter lying under it and covered by the edge of the tentorial portion of the dura mater, as it surrounds the crura. Basal Paralysis.—To make such a diagnosis probable, we must have all the branches of the third implicated, because integrity of the pupil and accommodation transfers the lesion to the nuclear variety. Again, the loss of the sense of smell is in favor of a basal lesion, although not with certainty, because that too may be nuclear. Optic neuritis has about the same relative value; its origin may be both basal and cerebral. Recurrent paralysis, especially of all the third nerve, is almost certainly basal. It hap- pens most frequently among young subjects. The periods may be within a few weeks, or months, or at longer intervals. It took place five times in a girl five years of age who was under my care. The duration of each attack may be for a few days or for weeks. ■"Die ursachlichen Momente der Augenmuskel-L&hmungen," Wies- baden, 1886, p. 393. 2 Archiv fur Augenheilkunde, vii., 94, 1878. BINOCULAR VISION AND ITS DISTURBANCES. 159 In most cases there is headache (migraine). The two cases where an autopsy was made disclosed in one an exudation and in the other tubercular deposit about the stem of the oculo-motor. Both sides may be involved, and Graefe reported five cases of paralysis of all the eye muscles of both sides with complete recovery; he be- lieved them to be basal and from cold, but about this localization there may be a doubt. An enumeration of the causes of basal paralysis will throw some light on its diagnosis. Their enumera- tion is borrowed from Mauthner,1 whose treatise on this topic is the most complete in existence and summarizes what is known at the present time. They are, (1) hemorrhages; (2) circumscribed pachy- meningitis about the nerve trunks; (3) meningitis, both simple and tubercular, and this often in children, sometimes getting well and at other times ending fatally; it may also be of traumatic origin, and the prognosis in all cases is serious; (4) abscesses, especially of otitic origin; (5) aneurisms; (6) arteritis obliterans, which impairs the nutrition of the nerves, and is often syphilitic; (7) neoplasms, including specific growths compressing the nerves, and sometimes filling their foramina; (8) idiopathic lesions of the trunks, viz., a, interstitial neuritis and perineuritis of tubercular or gummatous character; b, lymphomatous swellings in cases of lymphomatous disease, and c, gray degeneration consequent upon nuclear disease. We must study collateral symptoms carefully to form a prob- able judgment, such as variations in temperature and other signs of inflammation—the history personal and hereditary—not only the presence, but the absence of other cerebral disturbances. For example, tumor in the brain may cause nerve trunk lesions as well as if at the base, either by stoppage of the ventricles and internal hydrocephalus, or by pressure reaching to the base, e.g., paralj'sis of right sixth reported by Nothnagel from tumor in left hemi- sphere. But crossed paralysis of the third with hemiplegia, or with hemianopsia, brings us to the crus, and if the other oculo-motor is subsequently paralyzed, we may be sure that the lesion is in the vicinity of the crura as the third nerves enter the pons.2 Anaes- thesia or irritation of the fifth is not a distinctive sign, it may be basal or pontine. But anassthesia may come from a lesion higher up, viz., in the internal capsule at its caudal part. It is impossible writhin suitable limits to elaborate this topic; we can only call attention to the tokens from the olfactory nerve, the optic nerve, the auditory, the facial nerve, and to careful analysis, not only of what muscles are at fault, but of all other symptoms, 1 "Die ursachlichen Momente der Augenmuskel-Lahmungen," 1886. 8 See analysis of one hundred and fifty cases of brain syphilis with eye lesions, and autopsies, by W. Uhthoff—Graefe, Archivf.Oph., B. xxxix., Abth. 1, S. 1-182. 160 DISEASES OF THE EYE. whether general or cerebral, which may be used as clues. The rapidity of onset, spasms, the degree and location of pain, will all be considered. Neoplasms usually cause slowly progressive symp- toms. Yet this is not always true, because time may be required to develop disturbance, and periods of repose and aggravation may occur. Hemorrhages, embolism, and softening have their own features. Nuclear paralysis has certain characteristics. It is sometimes sudden, is usually slow in attack, and affects successive muscles; they may for a time act well and give out as the examination pro- ceeds; the affection is often incomplete; is apt to be worse at night or when fatigued; it may be unilateral or bilateral; usually there is no pain, yet pain may be severe. A very significant symptom is somnolence, and a most important sign is non-recognition of double images. Affection of the extrinsic muscles is called oph thal- moplegia externa; of the intrinsic muscles, the pupil and accom- modation being paralyzed, is ophthalmoplegia interna. The dila- tation of the pupil may be moderate. If one muscle after another fall a prey to paralysis we may consider the cause basal by certain correlative symptoms, but it may also be nuclear, and if, for ex- ample, the muscles animated by the oculo-motor on one side are involved at the same time with the trochlearis of the other eye, we know this is nuclear. There may be double ptosis of nuclear origin; single ptosis may be cortical, fascicular, or nuclear. See Gowers.1 Pfliiger2 reports a case of double trochlearis paralysis with partial paralysis of both oculo-motors, due to influenza or grip. Among oculo-motor nerves, the right inferior oblique, myosis of both sides—abated pupillary action both to light and convergence, paresis of accommodation both sides—these lesions must be nuclear. Paralysis of convergence without impairment of associated move- ment to the right and left is reported by Straub.3 I have re- cently had one such case. Seggel4 reports mydriasis of one e3'e, there being no response to light, but contraction upon con- vergence and accommodation, and no impairment of sight. De- fect of levatores palpebrarum and of both superior recti of con- genital type must be referred to the nuclei (see Gowers, 1. c). Graefe5 reported a case of a man with paralysis of the six external muscles of each eye, with good accommodation and normal pupils; this, of course, was nuclear. Paralysis of either the third, sixth, or seventh with crossed hemiplegia signifies hemorrhage into the pons. 1 "Diseases of the Nervous System," Am. ed., p. 620, 1888. 2 Graefe's Archives, xxxvi., 4, 71, 1891. 3 Archiv fur Augenheilkunde, xxiii., 3 and 4, S. 271. I have seen one case. 4Archiv fur Augenheilkunde, xxiv., 3, S. 234. 5 Archiv fur Ophth., ii., 2, 299. BINOCULAR VISION AND ITS DISTURBANCES. 161 If the lesions be in the upper half of the pons facial palsy may be on the same side with body palsy. The facial and sixth are some- times affected together on the side opposite to the limbs. The face and limbs palsied on the same side and the third on the opposite side points to the crus. There may be a lesion so small that the nerves escape.1 Lesion of the abducens nucleus with or without hemiplegia damages not only the corresponding rectus externus but also the associated rectus internus of the other eye, causing conjugate de- viation. This subject will be dealt with more at length when speaking of cortical lesions, which also cause this symptom. Gowers relates paralysis of elevators of both eyes by a tumor on the middle line of the fourth ventricle just behind the velum (see Fig. 73 from Perlia showing the vicinity of the superior recti and inferior oblique nuclei). A case seen by Dr. Starr2 and later by myself is instructive. The symptoms were temporary conjugate deviation to the left side, analgesia of left face and of right half of body; ataxia of right limbs without paralysis; he staggered in walking, had to be very cautious in going down steps; contraction of left pupil, paralysis of left trochlearis, anaesthesia of left cornea and beginning damage to its epithelium; urine sp. gr. 1040 and contained sugar. These signs placed the lesion in the left side of the tegmentum where the superior peduncle of the cerebellum comes in and near the trophic centre of the fifth nerve, very dorsad and extremely small (see Figs. 69 and 71). It touches the trochlearis nerve after its crossing and for a time stimulated the left abducens, thereby exciting, through its connection with the opposite rectus internus, conjugate devia- tion to the left. The irrit ation of the pupillary nucleus had per- sisted on the left side. The diagrams show the various possibilities of sensory disturbances due to the peculiar and interesting course taken by the various sensory tracts. Small hemorrhages and very limited lesions are possible in this region because the arteries are small, they supply very small territories, and do not inosculate with each other. They are technically " terminal" vessels. A fact of importance is, that the nuclei for the ciliary muscle and for the iris are supplied by a special arterial branch which has no rela- tion with the region in which the other nuclei are found. In this fact lies an explanation of some cases of isolated paralysis of these groups. Mauthner collects a series of instructive cases (1. c. pp. 311-3-28). See also Gowers' Lectures, 1887, Manual, 1888. 1 For illustration of such lesions with autopsies, see Uhthoff—Graefe, Arch., I.e. 2 Reported in full bv Dr. Starr in X. Y. Medical Record, Feb. 11th, 1893. 11 1(>2 DISEASES OF THE EYE. The complications may be loss of smell, which is rare; loss of sight due to optic atrophy and often syphilitic; both the motor and the sensory portion of the trigeminus may suffer, most frequently the latter; facial or hypoglossal palsy; bulbar paralysis, progres- sive muscular atrophy, deafness may co-exist. The sufferings of the poet Heine belonged to nuclear palsy. Graefe called attention to anaesthesia of the face, while on the other hand extreme neural- gia may co-exist, and insanity sometimes occurs. Locomotor ataxy, hemiplegia, hemiataxia, hemianesthesia, and general paresis may take place. Galezowski and Duchenne have seen cases of bilateral paralysis of the third and of the sixth in spinal disease. Lesion of the sixth is the most common. Unilateral lesions are common. In spinal cases the paralysis is likely to be incomplete and not to be permanent. No other sign of spinal-cord disease may occur for a long time, and the eye symptoms, while unsupported by others, will remain of doubtful significance. The motor nerves of the eye often become implicated at a late stage of spinal disease, and then the lesion is not transitory, but permanent. Implication of the optic nerve may be either an early or late symptom. In some autopsies (Leube), the trunks of the motores oculorum and of the sixth have been trans- formed into gray, thick, and hard cords. The Argyll -Robertson symptom "of early ataxy, that the pupils contract feebly to light and quickly to convergence and accommoda- tion, is explained by the most recent author1 as due, not to a nuclear lesion of the pupillary centre, but of the communicating fibres be- tween the optic tract and the pupillary nucleus. He quotes four cases of this symptom confined to one eye, and says that the lesion which then causes reflex pupillary immobility on one side, with re- tention of the consensual reflex, merely blocks the passage of the direct fibres from the optic tract to the oculo-motor nucleus on the same side ; while that which produces both direct and consensual immobility of the pupil on one side (assuming that there is only one lesion) occupies a position which blocks both the direct and the crossed system of fibres, i.e., in the sphere of the centre of the sphincter iridis. A lesion in the same region is usually extensive enough to implicate the above-mentioned fibres on both sides of the median line, i.e., the direct and the crossing, and hence the Argyll-Robertson pupil commonly affects both eyes. Fontan (see Mauthner) describes nicotine paralysis in which the extrinsic muscles are incapable of function and the pupil and cili- ary muscle irritated (myosis and spasm of A). 1 Turner: " On the Diagnostic Value of the Loss of the Pupillary Light Re- action, with a Note on the Oculo-Facial Muscular Group."—Ophth. Hosp. Reports, vol. xiii., partiii., 328, Dec, 1892. BINOCULAR VISION AND ITS DISTURBANCES. 163 Near the seventh cervical vertebra is the cilio-spinal centre which controls the vessels of the iris by the sympathetic nerve fibres. When they become paretic the iris vessels lose tone, dilate, and myosis ensues—the corresponding half of the face blushes and perspires. Orbital paralysis arises from inflammation of the connective tissue or from periostitis, from tumors, from wounds and injuries. Pain, tenderness on pressure or on percussion, are important signs. One must push the finger deeply under the rim of the orbit all around. The case will often have to be observed for some time before a conclusion can be reached. Finally, rheumatic or per- ipheral paralysis may occur, as from sitting in a draught, and the sixth nerve is oftenest concerned. Drs. Collins and L. Wilde (Am. Journal Med. Scieiices, Nov., 1891) have examined and tabulated 120 cases of ophthalmoplegia from which much valuable information can be gained as to their clinical histories and events. A useful summary of the possible causes and varieties of these cases is stated in their classification, which closely resembles that of Mauthner, v. s. Concluding now this imperfect sketch of causes and etiology, it remains to be said that fully one-half of all cases of ocular paralysis are due to syphilis and especially to the late forms. A study of Uhthoff's paper, 1. c, shows the special lesions to include gummy tumors and infiltrations; thickening of the meninges or periosteum; exostoses; degeneration of vessels, with consequent softening of brain substance, and also atrophy of the nerve trunks or nuclei; thrombosis, partial or complete; hemorrhages. The lesions may be single or multiple. At least two cases are given in which no lesion was found at the autopsy; which is perhaps not surprising unless the microscope was used, and the same writer, Howard, reports two cases complicated by exophthalmic goitre, which recovered.1 In addition the following etiological conditions may be found: cerebral hemorrhages, circumscribed pachymeningitis, meningitis on the convexity of the hemispheres, both ordinary and tubercular, abscesses at the base frequently arising from aural disease, en- largement of arteries, aneurisms, arteritis obliterans, tumors in- cluding gummata, idiopathic diseases of the trunks of the nerves at the base, such as neuritis, gummy degeneration, tubercular de- generation, lymphomata, gray degeneration. We have also pa- ralysis from diphtheria, from grip, from diabetes mellitus, from nicotine, from lead, and from injuries. Schoeler, out of 70 cases observed a long time, could determine the cause in only 64^. The chronic cases, which are the more frequent, arise from epen- 1 " Bilateral Ophthalmoplegia,1' etc., Am. Journal Med. Sciences, p. 238, March, 1889. 164 DISEASES OF THE EYE. dymitis with secondary affection of the gray matter of the ventricle- (polio-encephalitis superior) multiple sclerosis, and atrophy of the nuclei. Ocular paralysis in spinal cord disease may disappear and return. Pell1 reports the third nerve to have been affected seven times. Acute cases arise from inflammation of the gray matter of the third and fourth ventricles (polio-encephalitis superior of Wernicke) or from hemorrhage. As would be expected, diabetes not infre- quently exists. In acute cases, Wernicke has seen acute double optic neuritis. In chronic cases, the optic nerves may be atrophied or impaired or intact. Acute cases may be suddenly fatal, while a case of Etters, 1882, involving a series of nerves from the second to the eighth with profound paralyses, recovered almost entirely after seven weeks. Finally, this lesion is sometimes congenital, although some congenital defects in the eye muscles are due, not to paralysis, but to absence of muscles or their incorrect insertion or imperfect development. Fuchs2 describes cases of isolated double ptosis which he at- tributes to atrophy of the levatores muscles—i.e., a peripheral lesion; but he evidently has not weighed the reasons for assigning the nuclei of these muscles to the leading cephalic position which Knies has given them, else he would have been more likely to re- gard the pathology as nuclear in at least some of the cases. If disease involve the anterior quadrigeminal3 bodies there is amaurosis; in some cases the ophthalmoscope reveals absolutely nothing. In tumors we may have choked disc or atrophy of the optic nerve, etc. Generally the pupil does not react either way. Naturally we would look for lesion of the trochlearis muscles and probably of neighboring nuclei. Hemiataxia is very prone to occur, and simulates hemiplegia, but will be easily discriminated by testing the muscular force. It arises from interference with the superior cerebellar peduncles and with the crossing fibres of the pons and possibly with the vestibular nucleus of the auditory nerve. We have yet to consider cortical and sub-cortical paralysis of ocular muscles. (See Fig. 75.) We have stated that this form of paralysis is always conjugate—i.e., associated movements of the eyes are disturbed, and of course both eyes are affected. We have remarked, without dwelling on the point, that such lesions also take origin in the pons and can then be quite accurately localized. But we are far less able to determine the place affected when a lesion is cortical. The experimenters are not in agreement as to the cortical area. Horsley and Schaefer select a space in the frontal lobe, and 1 Berlin, klin. Wochenschrift, 1890, 1. 2 Graefe, Archiv f. Oph., xxxvi., 1, 234. 3 See Goldzieher, Centralblatt f. Augenheilk., Feb., 1893. BINOCULAR VISION AND ITS DISTURBANCES. 165 Ferrier chooses a somewhat less extensive area in the same region, in front of the head area, which gives rise when irritated to opening of the eyes, dilation of the pupils, and turning of the head to the opposite side, with conjugate deviation to the same side. In this view Mills concurs, 1888. Stimulation of the region just in front of and including the angular gyrus causes conjugate deviation to the opposite side. Wernicke thinks a lesion of the lower parietal region of the opposite side is denoted by conjugate deviation when it remains permanent. Temporary deviation occurs from stimula- tion almost anywhere in the cortex. It is a frequent phenomenon at the onset of cerebral apoplexj'. The rule is formulated as first given by Prevost, that irritation of one hemisphere causes the eyes to turn to the opposite side, an active effect—while paralysis of one hemisphere causes deviation to the same side, a passive result, because the opposite hemisphere excels in power. Usually the deviation lasts only a few hours or perhaps weeks. It often pre- vails during the comatose period and disappears as consciousness returns. A few cases of permanent deviation are recorded from lesion of the thalamus, but we cannot establish any connection be- tween the symptom and any definite cortical or subcortical region. It is very interesting that experiments on animals by Munk and Schaefer with weak induction currents have shown that irritation of the anterior part of the visual area produces movement of both eyes downward, and of the posterior part of the visual area move- ment upward. If the macula region of the visual area be stimu- lated no movement occurs, because it then seems as if the irritation proceeded from the point of fixation of the visual lines, and no change of direction ensues (Obrigia1). The farther from the macula region of the cortex (cuneus) is the part stimulated the more de- cided the movement of the visual axes and to the opposite side. Conjugate deviation from pontine lesion presents some varia- tions of type and may be either acute or chronic, temporary or per- manent. It is not admissible to enter at length into its discussion. There is a large literature on the subject, and a very full compila- tion is given at the close of an excellent article on eye paralysis by the late Dr. J. A. Jeffries.2 The thesis of Prevost, 1868, and a treatise by Hunnius, 1881, are valuable contributions, while Ross and Gowers treat of it at some length in their works on nervous diseases. See also Swanzy, Trans. Oph. Soc. United Kingdom, 1889, p. 6. Drs. Collins and L. Wilde8 have collected and classified 120 cases of ophthalmoplegia, and their arrangement of them corre- 1 Archiv f. Anat. und Phys., 1890, S. 260. 2 Boston Med. and Surg. Journal, Oct. 20th and 27th, 1892. "Am. Journal Med. Sciences, Nov., 1891. 166 DISEASES OF THE EYE. sponds closely to that of Mauthner. Dufour1 has compiled a large number without closely analyzing them. Prognosis must always be guarded. Recovery is frequent, but the possibility of progressive disease in the brain and spinal cord is not to be overlooked. There may be a long period of exemption from other trouble, but in the end mental disease, cerebral tumor, progressive paralysis, or locomotor ataxy may develop. If syphilis can be made out, treatment is more likely to be effective, yet not always. In the 120 cases collected by Collins and Wilde (1. c.) the recoveries were 24$; marked improvement 16$; death 24$. A diagnosis of the seat of the lesion, as well as its quality, is the most important element in prognosis, and justifies the elaborate discus- sion entered into on this point. Treatment.—We must necessarily take into account the proba- ble cause and localization of the disease, and when this is doubtful we fall back on general principles of therapeutics. A patient in the early stage of his trouble, who has double images, will close one eye, or wear over it a screen. It is well for short periods to put the screen over the sound eye, to keep the muscles of the other in practice. Soon after the lesion there may be headache or symp- toms which suggest leeches or cupping, but not often is depletion proper. Blisters by cantharidal collodion, of small extent, over the temples or forehead, are useful as peripheral stimuiants. Iodide of potassium would be given in small doses in non-syphilitic cases, and in large doses in syphilitic cases according to the stage and peculiarity of the constitutional disease. Electricity may be applied by the faradic current or by the interrupted galvanic current, the former preferabty—one pole upon the temple or behind the ear, and the other by a small sponge upon the globe. Its efficacy is, to say the least, very doubtful. Neurologists have recently been placing reliance on hydrotherapy in nervous affections, and this will have its application to patients in whom there may be ocular complications.2 It needs skilful management by well-contrived appliances and methods. We also use strychnia in moderate doses after a few weeks have elapsed. We chiefly rely on spontaneous absorption of the mis- chievous exudation or hemorrhage or thickening. In case of tumors or of organic cerebral or spinal-cord disease, our attention is neces- sarily chiefly given to them. Michel has proposed mechanical ex- ercise of the affected muscle by pulling the e3^e forcibly to the side toward which it cannot turn, by fixation forceps, having first in- stilled a solution of cocaine. This may be done once daily or once in twro days. Bull has found good results from the proceeding. 1 Annales d'Oculist. 2 " Hydrotherapy in the Treatment of Nervous and Mental Diseases," by Frederick Peterson. Am. Journal Med. Sciences, Feb., 1893. BINOCULAR VISION AND ITS DISTURBANCES. 167' When, however, no improvement takes place after the lapse of two or three months, we have little right to expect it; but in most cases, a degree of amendment or entire cure will have occurred. For stationary conditions when double images are not too wide apart, we may employ prisms. It is sometimes possible to wear prisms as high as 8° to 10°, but beyond this they become too clumsy to be ordinarily tolerated. In adopting them, this rule is to be remembered: Put the base of the prism toward the image which is to be influenced. The total number of degrees required may be divided between the two e\~es. The eye which deviates the most, or which is weaker in power or in vision, will wear the stronger prism, in case, as may happen, a difference is to be made. Frequently the muscles undergo changes, and require corresponding alterations of the prisms. The perma- nent use of prisms is in fact a rarity, and pertains more especially to cases of vertical diplopia. Double vision beginning 10° or less above, and for all the field below the horizontal meridian, or which concerns the median region of fixation, is the most distressing, and calls loudly for aid. The utility of prisms is usually confined to these regions, viz., on the median line and for parts on or below the horizon. In fact, to extend their influence over the whole field is impossible, because the relations of the double images become entirely different in its various parts, and it is impracticable to adapt prisms to these changes. Prisms, like crutches, may be greatly acceptable; but they are imperfect substitutes for sound muscles. When, however, a case has existed for months, and is beyond the utility of prisms, and does not improve, an operation will often serve an admirable purpose. Operative proceedings are twofold: 1st, simple tenotomy of one or more muscles; 2d, advancement of the impaired muscles. For such a case, for example, as imperfect paralysis of the sixth, or sometimes when it is wholly paralyzed, a tenotomy of one or both interni may be indicated and give a useful result. Both must generally be divided, because in the opposite eye the internus has undergone secondary contraction by co-ordinated function, and the internus of the impaired eye, by being unopposed, has passed into a similar condition. The greatest stress in such an operation is to be laid on the internus of the sound eye, because undue freedom in loosening the internus of the injured eye will tend to exophthalmus, to sinking of the caruncle, and to render the globe incapable of sufficient movement in any direction. On the injured eye, if any such tendency appear, a suture must at once be deeply entered, and drawn tight to prevent undue slipping back of the tendon. The effect on the muscles is to be measured by using a lighted candle, a red glass and prisms, and single vision must, if possible, be secured to a point far within the functional range of the paralyzed muscle. 168 DISEASES OF THE EYE. The ultimate effect will be less than the immediate. If any power remains to the damaged muscle, it gains increase of function by being less seriously overmastered. In fact, this principle has been applied to the advantage of a paralyzed muscle, to prevent both the degeneration of its own tissue and extreme secondary contrac- tion in the co-ordinated muscle, by performing tenotomy on a secondarily contracted muscle within a brief time, say two or three weeks after the onset of the paralysis. I have seen Dr. E. G. Lor- ing perform such an operation, and he declared himself satisfied with its effect. I have had no such experience, and do not know that such practice is pursued by any one else. The degree to which the muscle is loosened is very carefully measured and restrained, because the tenotomy is intended to have a preventive effect, and also to aid in the recovery of function. For cases of marked and permanent limitation of motion, the proper proceeding is combined advancement of the paralyzed muscle and setting back of one or more of its opponents. For a correct understanding of this proceeding some remarks on the anatomy of the oculo-orbital fascia are proper. This tissue is also known as the capsule of Tenon. If the upper and lower lids be divided in the middle down to the fornix and the flaps be forcibly drawn back, it will be seen, by lifting the conjunctiva on a probe or a strabismus-hook, that there is a distinct layer of connective tissue going forward under it to the margin of the cornea. It is also noted that the ends of the muscles, as they reach the globe, pro- trude through it and are clearly displayed. Pressure with the con- vexity of the hook between the eyeball and the margin of the orbit demonstrates that something shuts off the parts behind, and forms a layer which adheres on the one side to the globe, and on the other to the margin of the orbit. The structure which is thus demon- strated is the oculo-orbital fascia. If the globe be enucleated, the tendons and the stump of the optic nerve will be seen to stick out through a layer of smooth fibrous membrane, which forms the cup in which the globe rotates, and which is part of the same fascia. The same structure enters into the eyelids and enwraps all the muscles as they advance toward the globe. It thus appears clear that a tendon maj^ be entirely loosened from the globe, and if its lateral and immediate relations with the fascia are not torn up, it still remains in connection with the eye, and can exert an active, although reduced influence upon its movements. If, however, in detaching the tendon, cuts be freely made in the lateral regions, the muscle will lose its control over the globe, because it slips back into the orbit; and if any connection remains, it will be through the medium of some band of tissue which has escaped disruption. Motais has also shown that, after tenotomy, the reattachment of the muscle is more by the medium of the conjunctiva and capsule NOYES ON THE EYE. PLATE / k ljSc/— cf» i ccp c/ FIG./ FIG. 2 EXPLANATION OF PLATE No. II. Fig. 1.—Arrangement of capsule of Tenon in man. Vertical section pass- ing through the superior and inferior recti. CE, CE, CE (red), aponeurosis or external capsule forming sheath of mus- cles. CEP, CEP, deep layer of the sheath of the muscles folded backward upon itself to cover the posterior hemisphere of the globe. CEM, superficial layer of the sheath of the superior rectus muscle folded to form the sheath of the levator palpebr*. LT, LT, terminal layers of the aponeurosis going to the orbit, and tarsal cartilages. FS, FS, subconjunctival fascia. CI, CI (blue), bulbar or internal capsule, serous membrane of the eye. CI', internal capsule folded beneath the deep surface of the tendon and mus- cle which it covers to the point I, where the external capsule leaves the muscle. CI, internal capsule in front of the tendon and anterior extremity of the mus- cle surrounding a serous bursa indicated by a dotted blue line. It stops behind just where the external capsule leaves that muscle to go to the or- bit ; anteriorly it is inserted into the sclerotic with the tendon and does not reach the border of the cornea as does the subconjunctival fascia FS. ADI, aponeurotic offshoot of the inferior rectus muscle DI, split to envelop the inferior oblique muscle 01. DS, Superior rectus muscle. R, levator pal- pebral. LS, superior tarso-orbital ligament. LI, inferior tarso-orbital liga- >nent. TS, superior tarsus. TI, inferior tarsus. CON, CON, subconjunctival bpace. Fig. 2.—Arrangement of capsule of Tenon in man. Horizontal section pass- ing through the internal and external recti. CE, CE, CE, CE (red), aponeurosis or external capsule forming sheath of muscles, CEP, CEP, deep layer of the sheath of the muscles folded back- ward upon itself to cover the posterior hemisphere. ADE, external ligamen- tous offshoot. ADIN, internal ligamentous offshoot. FS, IS, subconjunc- tival fascia. CI (blue), internal capsule. CI', internal capsule folded beneath the ten- don and muscle to the point I. CI", CI", internal capsule in front of the ten- don and muscle which it covers up to the point I, where the offshoot leaves it; surrounding a serous bursa BS, BS, indicated by a blue dotted hne; it then terminates anteriorly at the tendinous insertion I'. DF, external rectus muscle. DI, internal rectus muscle. BINOCULAR VISION AND ITS DISTURBANCES. 171 of Tenon than by the tendon, and that both in retro-placement and advancement of the muscle the most important factor is the fascia and especially its lateral prolongations. The oculo-orbital fascia does not admit of a clear demonstration as a membrane; it is too complex in its ramifications, and too deli- cate in structure, besides being perforated by a multitude of organs. It ensheaths to a greater or less degree all the organs, muscles, vessels, nerves, etc., which pass through it. For example, the ex- ternal sheath of the optic nerve is continuous with it, and it also adheres to the margin of the optic foramen. The periosteum of the orbit is continuous with it, and is sometimes spoken of as its parie- tal portion. But the analogy of the pleura in its visceral and pul- monary parts cannot be strictly maintained, although it is sug- gested. For practical purposes we are to bear in mind three facts: 1st, that the fascia serves as a cup, like the acetabulum, in which the globe revolves and makes enucleation possible without opening the deep parts of the orbit; 2d, that it prevents effusions in the orbit from easily finding their way into the lid, and beneath the ocular conjunctiva; 3d, that it constitutes a secondary attachment for the ocular muscles, renders their combined action more perfect, and makes it possible to sever their tendinous insertions without annulling their influence over the globe. A further remark is that the caruncle and semilunar fold are intimately connected with the fascia; and so is the tendon of the muscle of Horner, at the inner canthus, while at the outer canthus the external lateral ligament may be called a process thrown out from the periosteum. Gerlach further calls attention to the check which certain fibres exert over the action of the muscles, and at the inner side of the orbit the figure which he gives shows how firm is the connection between the fascia and the bony wall. Motais more clearly demonstrates and emphasizes these restraining bands, especially at the inner and outer margins of the orbit (see Plate II.). It is always somewhat difficult to lift the caruncle in a dissection, and if this is done at an operation it is liable to retract and cause an unpleasant appear- ance. This has a practical bearing on the operation for converg- ing squint. Advancement of the ocular muscles is called for in three differ- ent groups of cases—viz., when the duration of the optic axes is due, 1st, to an injury or an operation; 2d, to spontaneous dissocia- tion from loss of sight in one or both eyes; 3d, to paralysis. In the first two the muscles retain a degree of contractility, in the last group there ma}T be none at all. Up to the present time I have made trial of many modes of operating, viz., those proposed by Critchett, by Agnew, by Weber, by Wecker, by Prince; and have modified them as circumstances de- manded, I have finally come to a method which has nothing but 172 DISEASES OF THE EYE. its simplicity to commend it and with which I am entirely contented. It is attended by very little reaction, which is far from being true of some other methods; it is exact and is capable of being grad- uated to a desired effect, whether this be large or small. The neces- sary instruments are a wire speculum, two pairs of strong fixation forceps, a good pair of scissors (Stevens pattern is the best), two strabismus hooks, a speculum, and three sutures of fine black strong silk with a curved needle at each end, and a needle-holder. The important thing is to have the needles fine, "half-curved," about | inch long, and ground so sharp that they can as easily penetrate the cornea as a discission needle. On the fineness, sharpness, tem- per, and curve of the needles, success chiefly depends. Suppose the right rectus internus is to be advanced. The right rectus externus is first divided; then seize the insertion of the rectus internus with fixation forceps, taking a deep bite to include all that can be lifted; sever the insertion freely and cut above and below into the con- junctiva to the extent of 10 to 15 mm.; leave the forceps fast to the tissues by shutting the spring catch, lay it aside, and then remove a vertical oval of conjunctiva in front of the insertion, leaving a strip 6 mm. wide next the cornea (this step may be deferred to a later period, in some cases depending on the laxity of the conjunc- tiva). Lift the muscle and pass a curved needle from within out- ward at its middle and as far back as the proposed effect will demand. With the needle in place cut off superfluous material lying in front of it; then draw it through. Insert another needle in a similar way, and before drawing it through cut away superfluous material. Do the same with the third needle and cut off needless material as before. The object of cutting off re- dundant substance in successive parts as the needles are inserted is, to be certain not to sever the sutures. We now have three threads through muscle and fascia and conjunctiva. The needles at the other end of the threads are next to be passed forward beneath the remaining conjunctival strip, taking hold of the outer layer of the sclera so that the points emerge at the lim- bus corneae; the middle one must first be fixed in situ. To get them through without breaking, they must be seized at the middle and pushed without any lever action. If the globe tends to rotate it may be steadied by a bident. I have seen the points sometimes appear in the anterior chamber, but this is of course too deep. What is essential is to have firm hold on the sclera. In tightening the threads begin with the middle, and care must be used not to pull too hard and to act first on one and then on another, deferring the second knot until each has been pulled up as far as it will bear without breaking. If there is much crumpling of tissue it must be cut away and the parts be left smooth—perhaps some additional and superficial stitches will be needed. I know of nothing more BINOCULAR VISION AND ITS DISTURBANCES. 173 simple than this proceeding. Its effectiveness depends on the firm hold obtained by piercing the sclera close to the cornea, and to this end the needles must be adapted. The stitches will remain from four to seven days. When the utmost effect is desired the externus of the fellow eye must be divided. A bandage is applied for twenty-four or forty-eight hours, and afterward cold-water compresses em- ployed. It is rare to have chemosis or any important reaction. The degree of effect must be in excess of what will be ultimately required, because the eye will slip around some 5 or 10 degrees. In case we have to do with an eye which has had a too liberal tenotomy as the cause of the deviation—the dissection of the muscle is more difficult, but the method is the same—I find no need of the hitching thread of Dr. Agnew, nor of the clamp forceps of Wecker, nor of the anchoring thread of Prince. The ordinary fixation forceps, aided sometimes by a second one, each having a spring catch, gives perfect control of the muscle. The operation on the rectus externus is much easier of execution than on the- rectus internus. Strabismus hooks are used in exploration and as accessories, not as essential implements. This mode of operating is especially, but not exclusively, suited to strabismus paralyticus, and hence is now described. Still other proceedings will be referred to, adapted to ordinary kinds of stra- bismus. Advancement does not confer contractility upon a totally paralyzed muscle, but simply gives the globe a more pleas- ing position. It may give rise to annoying diplopia, but this is usually temporary. Congenital paralysis of ocular muscles sometimes demands relief, and its most frequent form involves the levator palpebrse superioris and the rectus superior together, causing ptosis and dropping of the eyes. I have seen excessive contraction of the in- ferior rectus drawing the axis of one eye far below the position of its fellow, while in both the above-mentioned paralysis existed. Usually both eyes are symmetrically affected. I have also seen congenital paralysis with contraction drawing one eye downward and outward, while the other was normal. Some cases are doubt- less nuclear, while it has been shown that in some the muscles are not properly developed. Surgical relief is in some cases possible, in other cases quite unsatisfactory. If, as I have seen, the superior recti and the levatores palpebrarum are wholly incapable of action, only slight improvement and that of little value may be possible. If some power remains to the muscles there will be more encourage- ment. SPASMS OF OCULAR MUSCLES, NYSTAGMUS. An oscillatory movement of both eyes, quick and jerky, greater at some times and in some positions than in others, is the charac- teristic of this disease. In very rare cases one eye alone is affected.. 174 DISEASES OF THE EYE. Such a case was reported by Dr. St. John to the New York Oph- thalmological Society, in December, 1882. The condition is usually congenital. It is almost always associated with amblyopia, while it of necessity much impairs the available acuity of sight. We often find it with congenital cataract, both partial and total, also after ophthalmia neonatorum with central opacity of the corneas; it is almost invariable in albinoes, and we see it in cases of extreme hyperopia, and sometimes with congenital choroiditis at the macula. Frequently there is convergent strabismus. The movement may be lateral, vertical, or rotatory, or all combined. I saw, by ^he kindness of Dr. H. W. Williams, of Boston, a man who had ac- quired the power of voluntary nystagmus after having been for some eye trouble confined for several weeks in a dark room. A form of n3Tstagmus, lately noticed, affects individuals among high mountains, and especially those who work in mines. It comes in adult life, is most noticeable toward night, is periodic or parox- ysmal, is induced by looking in certain directions, and apt to be attended with vertigo. Nystagmus among the English miners has been described by Oglesby, and is attributed to their unhealthy surroundings and the awkward posture of the head and the straining of their eyes upward as they work. By refraining from work some seem to get well, only to relapse on returning to the mines. Commonly the patients are not aware of the oscilla- tions, except by the effect upon sight. The movement ceases during sleep. Rarely there is movement of the upper lid syn- chronous with the eye: this happens usually with vertical nystag- mus. Some persons, despite this trouble, have highly useful vision. They are apt to be myopic, and distant vision is below the standard, but near work may be prosecuted with great success. In New York I have known two notable cases—one a distinguished musical composer and teacher, and the other a well-known practical chemist. Both of them were albinoes. This condition is sometimes dependent on brain-lesions of recent occurrence. For example, it has been seen to follow blows on the head, also apoplexies, but with no definite localization, and in soft- ening, as well as in hemorrhagic pachymeningitis. In some chronic brain diseases it has been noted, and the matter has been summed up by Robin (" Des Troubles Oculaires dans les Malad. de FEnce- phale," 1880). "Nystagmus, unilateral or double, permanent or temporary, exhibiting itself with other convulsive or with paralytic symptoms, indicates an encephalic lesion. In general this will be at the base or on the convexity behind the fissure of Sylvius (region of the angular gyrus). In the former case, it will often be com- plicated with paralysis of the motor nerves of the eye or of the optic; in the latter case (when on the convexity), there will be BINOCULAR VISION AND ITS DISTURBANCES. 175 epileptic attacks, hemiplegia, etc., but we cannot venture on any exact localization." Irritation of the peduncles has caused this symptom in experiments by Schiff. It occurs among the insane and the neurotic. It is very frequent in disseminated sclerosis of the brain and cord. With locomotor ataxy it is very rare. A not in- frequent picture in a case of brain disease of the kind now noted, is the concurrence of rotation of the head, conjugate deviation of the eyes, and nystagmus; these phenomena evidently point to irritation of the region of the third and fourth ventricles. Nystagmus may be seen in cases of aphasia and of labio-glosso-larjmgeal paralysis. It thus becomes evident that, while most cases exhibit a complex causation, consisting both of defective sight and of irregular inner- vation of the muscles, other cases depend alone upon lesion of inner- vation of central origin. As to the former class of cases, it can- not be doubted that the irregular movements are, in very many, due simply to the want of motive for correct binocular fixation, i.e., to lack of predominance of the macula lutea. Treatment of these cases is of little service. For some the cor- rection of optical errors, so far as it can be accomplished under the difficulties of the examination, is valuable. For those with strabismus con vergens, tenotomy of one or both intern i is advisable. I have done tenotomy of the interni when no strabismus existed, but because the lateral movements were excessive, and found ben- efit ensue. The degree of tremor was abated; but, as a rule, an operation is not fitting. Albinotic patients wear dark glasses, and preferably those with side-pieces to cut off the glare of light; and all nystagmic patients hold fine objects close, and have some choice position of the head in which their trouble is less annoying. Ex- citement greatly aggravates the tremor, and it usually remains unaltered through life. For an exhaustive study of nystagmus, see an article by Raehlmann: Arch, fur Oph., XXIV., 4, pp. 237-317. His conclusions tend to locate the cause of the disease in the brain, but at what region is undetermined. Another elaborate article is by R. P. Oglesby: Brain, vol. ii., July, 1880. (See Gowers, "Dis- eases of the Nervous System," 1888.) A paper by Alfred Graefe (Bericht Siebenter Internat. Ophthal- mologen Congress, 1888, Wiesbaden, p. 30) discusses cases of palsy of lateral movements with unimpaired convergence ; that is, only the associated movements of interni and externi are abolished. I have seen two cases of the affection of a chronic type ; one was for four and a half months under observation. It seemed to point to a growth in the vicinity of. the left abducens nucleus. 1882 May 6th Henry R, aged 17, Brooklyn, ship carpenter; came to New York Eve and Ear Infirmary. Father living and healthy, mother died of cancer eighteen months ago. General health good, denies and has no signs of svphilis ; never had much headache. Seven weeks ago, had diplopia on 176 DISEASES OF THE EYE. median line and more noticeably on left side. Was treated by iodide of po- tassium and electricity. Now cannot bring either eye to median line, each turns to the right and stops about 10° to right of it: the head turned a little to right. On the left side has homonymous images, which implies that left externus is more faulty than right internus. It is found that right internus turns farther toward median line with effort of accommodation. On June 16th did tenotomy of right externus; this improved position to slight degree. On June 26th tenotomy of left internus, but eyes could not be moved beyond median line. Meanwhile electricity and full doses of iodide of potassium were kept up. Vision from the beginning normal in O.D. and § % in O.S. The temporal halves of each nerve look suspiciously white. July 7th, upper lid of left eye does not readily shut (suggests indication of facial nucleus which is near nucleus of sixth nerve) and sleep became bad; no headache. Begins to be light-headed; walks well with closed lids. On July 14th was sick at stom- ach after drinking ice water; after a week again felt perfectly well. Sept. 15th has almost complete facial palsy of left side; movement of left eye up and down is free, but lateral movement outward extremely limited. Right eye moves well, up and down, but cannot reach median line, and excursion to its temporal side is limited. Head trembles, gait frequently unsteady; some- times is dizzy; no other symptom. Not seen after this date. Diagnosis is tumor in left side of pons, involving nucleus of sixth and later of seventh nerves. Patient was seen by Dr. Allan McLane Hamilton, who concurred in this opinion. I have seen a child 2i years old with somewhat similar conditions. In the beginning, after fever and vomiting, the eyes were turned upward for two days and then settled down to the lateral dextral deviation and were parallel, although capable of convergence. She had enlarged lymphatic glands in the neck and face. I saw her for only a short time and know nothing of the ulti- mate issue. I witnessed the autopsy of a man 40 years old who had this symptom and who was under care of Dr. Janeway. He entered Bellevue Hospital uncon- scious ; both eyes and the head were turned to the right. He was hump- backed. At the autopsy the lesions found were abundant small tubercular deposits over the whole surface of the brain and more numerous at its base; acute meningitis of orbital surfaces of both frontal lobes and each in equal degree. Tubercles numerous on under surface of cerebellum and along spinal cord; the bodies of the vertebrae absorbed. Brain congested and oedematous, not soft, no apoplexies, nothing in ventricles nor in pons or in fourth ventri- cle. All the lesions were on the surface and mostly basal and anterior. Dur- ing life no choked discs. Such a case resembles more the epileptoid cases than those with distinct focal lesions. CHAPTER IX. STRABISMUS CONCOMITANS. This term denotes a condition in which either eye can fix upon an object in all parts of the field, but binocular fixation fails. The defect is not in the motility of each eye singly, but in the lack of co-ordinating power with its fellow. Associated movements are performed, but the deviation between the visual lines is always maintained, although its degree may vary according to the dis- tance and position of the object. Sometimes binocular fixation is possible for extreme distance, but is lost when the object ap- proaches. In strabismus paralyticus the essence of the lesion is loss of power, while in strabismus concomitans the muscular ac- tivity is perverted, not materially diminished. Again double vision is exceptional in strabismus, and is the rule in paralysis for certain parts of the field. Strabismus is either permanent or occasional; it sometimes is truly intermittent. It increases as the object approaches, that is, with efforts of accommodation, and, as said, it may only then ap- pear. This is always characteristic of converging strabismus, while with diverging strabismus the rule does not always hold good. According to the direction of the deviation we have S. conver- gens, S. divergens, S. sursum-vergens (upward), S. deorsum-vergens (downward). With converging squint the eye often turns up as well as inwTard. The affection is usually bilateral (concomitant), sometimes it is confined to one e3^e and is monolateral. Sometimes with bilateral squint the person will fix indifferently with either eye; more frequentry one is preferred to the other, and it may even be impossible to employ the eye which habitually deviates, for more than a few minutes. Of course with monolateral squint the devi- ating eye never voluntarily fixes and often cannot fix accurately and centrally. To decide between monolateral and alternating squint, a screen or the hand is placed obliquely over one eye, and while the other looks at the finger held near it, we note the behavior of the cov- ered eye; by trying each eye in succession we discover whether one or both is distorted. Frequently the angle of deviation is greater in one than in the other. It must be admitted that in ordinary squint, especially converging, there will be some limita- tion in mobilit}', but this is far less considerable than in paralysis. Patients are often distressingly conscious of paralysis, usually they give little attention to subjective symptoms in strabismus. 12 178 DISEASES OF THE EYE. Measurement of the degree of strabismus has been made by in- struments which give the amount of turning in millimeters or lines along the border of the lower lid. This is of course very inexact, and the only correct method is in terms of angles. To do this with precision one may, as Landolt suggests, use the perimeter. Place the squinting eye in front of the centre of the arc, let the other fix an object at ten or more feet distance nearly on the line of the centre of the arc—then carrj^ a small flame along the arc until it shall be reflected from the summit of the deviating cornea and read off the angle on the perimeter. If the eye deviates so far in- ward as to be behind the nose, a prism with angle inward may be interposed and half of its angle added to the number of degrees given by the perimeter. Another and simpler way given by Hirschberg is that the ob- server sit facing the patient and hold a lighted candle about one foot in front of him, screening his own eye from the light. From each eye is seen the reflex of the flame on the cornea. The eye at the centre of whose pupil the reflex appears is the one which fixes —on the other cornea the reflex is eccentric. Its place may vary as the patient gazes at the candle or afar off. The point at which the reflex appears will give a measure of the angle of the squint, and five degrees may be distinguished if the pupil be supposed to be 3..5 mm. in diameter. If the reflex be only a little way removed from the centre, i.e., about half wray to the pupillary edge, the devi- ation will be less than 10° (varying with the angle alpha as will be explained). If at the pupillary edge, the angle will be 12° to 15°. If at a point about midway between the pupillary edge and limbus, the deviation will be about 25°. If at the edge of the cornea, the quantity will be 45° to 50°. If outside the cornea, the reflex will be blurred or multiple and the angle may reach 60° to 80°. With normal fixation of both eyes, there may seem to be diverg- ence, if the corneal axes lie to the outer side of the visual lines— that is, if the angle gamma is large (see page 15) and positive. On the other hand, if the corneal axis lie to the inner side of the visual line, which occurs in high degrees of myopia, there will be an ap- pearance of convergence. In these cases the angle (gamma) is un- usually large and in the first instance is positive, in the second is negative. (The angle in question is really formed between the axis of the cornea and the line of fixation, which passes through the centre of rotation of the globe and is not identical with the visual line. This is the angle gamma. The angle formed between the axis of the cornea and the visual line is the angle alpha. Donders speaks of the latter and when his treatise was written the above distinc- tion was not made.—Woinow.) STRABISMUS CONCOMITANS. 179 To determine the error in terms of angles both Hirchberg and Landolt have constructed diagrams to be hung on the wall, in which vertical and horizontal lines are drawn at the distances corresponding to the tangents of angles from 5° to 60°. Priestley Smith achieves the same result by the ophthalmoscopic mirror and a tape measure. The light is put above the patient's head. He holds one end of a tape line one metre long against the cheek below the sound eye. The observer sits in front and the tape is held tense by a ring through which is slipped the handle of the ophthalmoscope. The good eye fixes on the mir- ror and the observer notes the position of the corneal reflex, which should be near the centre of the pupil. The light is shifted to the other eye and the position of the reflex on its cornea noted. The patient is directed to follow the finger of the observer's free hand as it passes outward until the corneal reflex on the squinting eye occupies the same position in the pupil that it did on the fixing eye when it looked at the mirror. The distance between mirror and finger is the tangent of the angle of deviation, and is denoted by figures on another tape of which one end is fast to the ring on the handle of the ophthalmoscope and which slips through the fingers of the moving hand. A tolerably precise mode of detecting deviations of the ocular axes, or lack of fixation by one eye, is furnished by the ophthalmoscopic mirror. Priestley Smith draws attention to it (Ophthalmic Review, Feb., 1892), but most experienced observers have probably employed it. The patient looks at the mirror or at the observer's forehead; the place of the corneal reflex within the illuminated pupil is noted ; without any change of the posi- tion of the observer or of the patient, the mirror is rotated to the other eye, and the place occupied by the reflex within that pupillary area is noted; the light is quickly flashed from one eye to the other, and a comparison of the relative situations of the corneal reflex will soon determine whether both eyes are fixing on the same point. Normally the reflex is a little nearer the inner edge of the pupil than the outer edge, because the line of fixa- tion does not coincide with the axis of the cornea {vide supra). A markedly non-symmetrical position of the two reflexes denotes failure to fix on the same point. If the discrepancy remains always the same and affects each eye alternately we may conclude that while both eyes do not fix on the same point each has the power of fixation, but fusion is absent. If how- ever one eye fixes correctly when the patient is told to look at the light, and the other persistently deviates in spite of the urgency to fix the light, we conclude that there is extremely defective sight in the wandering eye (probably a central scotoma) and that binocular correct fixation will be impossible, even by operation and other means. Etiology.—It has already been remarked that we are to look for the effective cause of functional strabismus, in errors of sight and not primarily in lesion of the muscles. The errors are those both of refraction and of perception. That the muscles themselves have a part to perform in causation must also be recognized. Their influence was formerly exaggerated, it has until lately been unduly depreciated. That hypermetropia is found in three-fourths of the cases of strabismus con vergens, was one of the brilliant facts made known by Donders. He set forth what is now so well understood, that in- creased convergence makes augmentation of accommodation more easy. If in a case of hypermetropia the renunciation of binocular 180 DISEASES OF THE EYE. sight were a lesser ill, than the strain on the accommodation with binocular sight, then converging squint would follow. This would take place when the two eyes differed greatly in refraction, if one were highly astigmatic, or if in one there were opacity of the cornea or lens, or if in one there were great amblyopia. Again Donders took into the category of causes decided weakness of the recti externi. Such are some of the conditions which caused him to say that hypermetropia is the dominant and sufficient cause of strabismus convergens. On the other hand he also showed that strabismus divergens is in the large proportion of cases associated with myopia. The cause here lies in the inability to maintain the needful convergence for a very near point, and such is largely the true explanation. That hypermetropia does stand related to strabismus conver- gens in a most intimate way is indubitable. That the connection is so simple as Donders' theory makes it, is not now accepted. The difficulty lies in the fact that a large number of hypermetropes, even when their eyes are unequally erroneous, do not squint. The number of those who do not squint is far higher than of those who do. Still more must we study the question with care when it is re- membered that converging strabismus belongs chiefly to the early age of life, and that at this time it is almost the absolute rule to have hypermetropia. It is also true that hyperopics learn to accommo- date with small effort of convergence. Why in some of them con- vergence should so far go ahead of accommodation, remains to be explained. It is admitted that the strabismic cases are not found chiefly among the strongly hyperopic, but among those who have medium and slight degrees. Donders assumed that the greatly hyperopic patients see so badly that they give up the effort to im- prove their vision. But we do find them converging very strongly in trying to see as well as possible. Defects of perception have been mentioned. Monocular ambly- opia is very common in strabismus convergens and not infrequent in S. divergens. This may or may not be associated with high degrees of hyperopia or with astigmatism, possibly irregular. We meet with it where the degree of ametropia differs little from that of the eye with good vision, and in a very large proportion, perhaps in the majority of cases, no lesion can be found with the ophthalmoscope. On this point it is important to bestow careful attention. ,No small number of cases exhibit what are evidently congenital abnormities in the papilla. In my records are such conditions as follows: An extraordinary amount of pigment deposit along the border; the presence of connective tissue on edge of nerve and running along the vessels (not to be confounded with opaque nerve fibres); a dull or slaty-colored and opaque disc with hazy edges; extreme hyper- aemia both of capillaries and veins; the nerve swollen as in papillitis STRABISMUS CONCOMITANS. , 181 a dark gray or slaty spot upon the disc and the rest of the surface an opaque white; coloboma of the sheath of the nerve or a very deep and irregular excavation which was so interpreted. Besides, one must carefully scrutinize the macula and it must be done with dilated pupil. Not rarely will one find minute specks, white, yel- low or glistening, clustered here, which indicate lesion either of the choroid or retina. There may be one or more marked pigment specks which will denote a previous inflammatory lesion. A nota- ble number of cases, and the majority, will not reveal any visible lesion. In the examination of the visual field we are often pre- vented irom attaining exact knowledge by the extreme youth of the subjects. When, however, they are sufficiently intelligent, we frequently find that the amblyopia is central and a defined scotoma for red may be sometimes mapped out, provided a small card 5 mm. square and dim light be employed. The scotoma may be very small and will be better discovered on a dark plane surface than by the perimeter. It may often be detected by the fact that out of a row of letters at 20', say tlie line O H SU E or 0.3, the S pointed out by the physician's finger is less clearly seen than the adjacent letters on either side. Sometimes a patient will say that over a small space, not the blind spot of Mariotte, a small candle flame is not perceived. This means a small absolute scotoma. In one case I found nasal (medial) amblyopia with the line of demarcation ver- tical. It was not difficult to show the decided difference in percep- tive power of the respective halves of the retina—this might be called hemiamblyopia. It was of course natural for this patient to have converging strabismus because then the better half of the retina was put to use. The amblyopia of strabismus has been attributed to non-em- ployment of the squinting eye, and amblyopia ex anopsia is often set down as a sufficient statement of the facts. The exclusive use of one eye does not in monocular cataract nor in extreme monocular astigmatism bring about amblyopia. Neither could dis- use occasion a central or localized scotoma, neither could a clearly defined hemiamblyopia which corresponded exactly to the fasciculus non-cruciatus of the optic tract, be caused merely by disuse. In truth this assumption rests upon no evidence. On the other hand, congenital amblyopia is not at all rare; witness its frequency in congenital cataract. Neither is congenital monocular ambly- opia rare. On this point Schweigger'sl statistics are eminently forcible, page 91. He collected ninety-eight cases of congenital amblyopia who did not squint. There were all possible refractive errors in every possible combination; in some, one eye was normal, and the other amblyopic. Out of them 47$ were hypermetropic —yet none of these patients squinted. On the other hand (pp. 1 " Klinische Untersuchungen tiber das Schielen." Berlin. 1881. 182 m DISEASES OF THE EYE. 99, 100 1. c), out of 247 cases of strabismus both converging and a few of diverging, which were at the same time hyperopic, he sets apart as amblyopic, those whose vision is less than \ and they are 87, that is, 35.2$ of the whole. He also divides these cases of hy- peropic squint into two classes, viz.: those in whom H is less than fj = 177, and those in whom it is above ^, i.e., 3 D = 70. In these two classes the chosen degree of amblyopia, viz., v = \ and less, exists in the first in 31.6$ and in the second in 44.2$. This increase in the ratio of amblyopia with the increase of the degree of hyperopia points unerringly to the dependence of amblyopia upon congenital defect and not upon disuse. My own attention has been carefully given to this question and I have on record a very large number of hyperopics who have monocular amblyopia and have never had squint. They at the same time have adequate muscles and binocular vision. The same is true of astigmatics, and my conviction is settled, that amblyopia is, with very few exceptions, precedent to squint and is not its effect.1 In a limited sense disuse operates unfavorably upon visual acuity. The power of fixation is much impaired, there is imperfect control of the accommodation (I have the record of one unmistak- able case of severe monocular spasm of accommodation in converg- ing squint) and the retina is easily fatigued. Perhaps the temporary scotomata and limitations which Wilbrand describes in asthenopia (1. c.) also occur. These conditions are readily admitted and they account for some of the feebleness and for the variability in the visual acuity. Beyond this degree, amblyopia ex anopsia has no proof to rest upon and it cannot be accepted as an explanation. With this opinion, which Schweigger first forcibly enunciated, agree Alfred Graefe, Ulrich, Segger, Landolt, Wadsworth and others. It therefore follows that amblyopia congenita is entitled to a place alongside of hypermetropia in the production of converging squint. But while the proportion of H in squint is about 75$ excluding those less than 2 D, the remaining 25$ must be accounted for by other causes. And we have seen that the great number of hyperopics do not squint, hence still another factor besides refractive error and amblyopia must be found. This evidently lies in the condition of the muscles. To this point Schell,2 Ulrich3 and Segger4 have given attention. Schell studied the ratio of abduction to adduction in a 1 See Wadsworth, " The Amblyopia of Squint," Boston Medical and Sur- gical Journal, Jan. 20, 1887. 2" Cause and Prevention of Squint." Amer. Journ. Med. Sci., Oct., 1-878 p. 418. 8"Zur Aetiologie des Strabismus convergens." Klin. Monatsbiatter, xviii., 156, 1880. " Die Aetiologie des Strabismus convergens hypermetropi cus," Kassel, 1881. 4 " Statistischer und Casuistischer Beitrag zur Aetiologie des Strab. con verg." Klin. Monatsblatter, xviii., 439, 1880. STRABISMUS CONCOMITANS. 18:1 small number of cases of emmetropia and hypermetropia. For 20 cases of E he found abduction was to adduction in the ratio of 28 to 100; while in 16 cases of H he found the ratio to be 48 to 100. The hyperopic cases did not squint. And the reason which Schell assigned was the relatively high capacity for abduction which they possessed. The contrary condition he assumed would favor the production of squint. Ulrich and Segger agree in the same view. Ulrich (1. c, p. 26) puts the ratio between abduction for 10 inches (M. 0.25) and abduction for 6 M. (parallelism) in E at 1: 5.7, in hy- peropia at 1 :.3 That is in hyperopia, abduction in the relations in which he compares it, is nearly twice as strong as in emmetropia, among those who do not squint. The results of Schell and Ulrich correspond with sufficient accuracy. With these three factors, viz., hyperopia, amblyopia and inadequate abduction, we have the combination which suffices to explain the larger number of cases of strabismus convergens. We may also include among them the cases of monocular ametropia, or opacity of the cornea and monoc- ular cataract. Even when the vision of each eye is good we meet with converging squint, and in these cases we may assume that the abduction has been abnormally weak. Such for instance is the explanation of many cases in whom we are told that the error came after scarlet fever, measles, or diphtheria, etc., or after an attack of acute inflammation of the eyes with blepharospasm. The assump- tion that it was produced by imitation of a squinting person, or by looking at a bright light, or a hanging lock of hair, etc., is of doubt- ful value, but need not be rejected as absolutely worthless provided other conditions concurred. Something must be said as to the phenomena of vision in persons who squint. That they do not complain of double images is not surprising when there is decided monolateral amblyopia—neither is it surprising after the full establishment of the deviation, even when both eyes have tolerably good vision, say better than |. But it is not true that in converging squint they make no use of the de- viating eye in conjunction with the other. Schweigger showed that they can always perceive the light of a candle if reflected into it by a small mirror placed beside the nose; a slip of plane glass will suffice. While ordinary binocular vision is of course impossible, there is by help of the faulty eye enlargement of the field, and in some cases it is proven that a real co-ordination between the two eyes is established by which the macula of the sound eye is coupled with some other spot of the retina of the deviating eye, which takes on the usual functions of the macula. In these cases prisms with the angle vertical, placed over the squinting eye cause diplopia, by the stereoscope the two figures are combined, and if by tenotomy the deviation be corrected, there may be crossed diplopia notwithstand- 184 DISEASES OF THE EYE. ing the ocular axes are in correct position. These are very puzzling facts in the physiology of vision. On the other hand if vision of the two eyes be nearly equal, the beginning of strabismus is at- tended with diplopia or there is a conflict in the impression of the two eyes which leads to the mental suppression of one image. This act of mental exclusion is familiar to microscopists and watch- makers, and it can be more or less perfectly realized in strabismus. This is the only explanation which can be offered of certain cases and it is not inconsistent with remarks before made, to assume that the mental impression of one eye becomes habitually weakened and in this sense vision may be said to be impaired by disuse. Some strabismic patients have double images when they give attention to both eyes. In most, it is very difficult to excite them. An oblique posture of the head is common with converging squint and it may persist after an operation. Some persons who use each eye alternately will employ the right for objects on the left side, and the left eye for objects on the right side, and change the obliquity of the head correspondingly. In doing this they evidently favor the weak externi. A distinct tremor when the eye turns in the direction of the weak muscles is not uncommon, it may be a real nystagmus and it may be monolateral. It is not infrequent to find symptoms of asthenopia, and these may be of a pronounced type, in some cases attended by photophobia. Fatigue in eye work is very common. Many interesting questions arise in connection with the vision of persons having strabismus, and for their discussion the reader is referred to the authorities quoted by Alfred Graefe in Graefe and Saemisch," Handbuch," B. VI., p. 242, and to authorities quoted by Landolt, article Strabismus, " Dictionnaire encyclope- dique des sciences medicales," Dr. Dechambre, which is brought down to 1882. Von Graefe, Donders, Javal and Alfred Graefe have especially interested themselves in this matter. Course of Strabismus.—Beginning usually at the time when steadfast application begins, it at first is occasional, and months, or years, generally elapse before it becomes permanent. It may show itself in rare cases at birth or under one year of age, generally it appears at two to six years. That it can occur in later life has been remarked. It may spontaneously disappear and this not ex- clusively in cases whose degree is small. Binocular vision is not established and critical examination may discover that there has been only a great abatement of the fault, not its complete disap- pearance. Usually the deviation lasts many years, and the rule is that when once established it permanently remains. We have no information upon the anatomical condition of the muscles in per- manent strabismus and it is desirable to fill this void. That the contracted and the enfeebled muscles undergo organic changes of STRABISMUS CONCOMITANS. 185 tissue is extremely likely. It is often found in operating that the muscles seem rigid as well as hypertrophied—but inasmuch as we come in relation only with the tendon we usually discover nothing of the status of the muscle itself. The remarks hitherto made apply chiefly to strabismus conver- gens. Schweigger gives the following statistics as to the refraction. He classifies the cases according to the refraction of the fixing eye, and mentions, but does not specify, anisometropia among them. Permanent Periodic Strab. conv. Strab. conv. . 85 13 Emmetropia,. Myopia, Hyperopia, Emmetropia, Myopia, Hyperopia, . . 44 10 . 196 98 325 121 Permanent Strab. divergens. . 37 . 59 4 446 Periodic Strab. divergens. 28 50 5 100 83 183 629 Out of Horner's clinic Isler1 collected 359 cases of strabismus. Strabismus convergens 236; Emmetropia, . 4 Myopia, . . 11 Antimetropia, . 13 Hyperopia, . . 208 Strabismus divergens 133 Emmetropia, . . 3 Myopia, ... 62 Antimetropia, . 30 Hyperopia, . . 38 236 133 In Isler's statistics the ratio of hyperopia is higher than in Schweigger's, because he not only takes in H less than 2 D which Schweigger excludes, but he comprises latent as well as manifest H. The discrepancy in regard to the ratio of E is partly explained by the fact that Schweigger's classification is based only on the fixing eye. He finds a higher ratio of myopia in converging squint than does Isler, viz., 8.6$, as against 4.6$. It is, however, very noteworthy that myopia takes the first rank in the causation of diverging stra- bismus. Schweigger gives 59.5$ and Isler, when the cases of anisome- tropia of which one eye was myopic (1. c, p. 28) are added to those of myopia, viz., 22 + 62 = 84, gives 63.1$ to myopia. In the latter's 1 " Studien fiber die Abhangigkeit des Strabismus von Refraction." Inaug. Dissert., Zurich, 1880, "Walter Isler. 186 DISEASES OF THE EYE. statistics an unusually high proportion of cases of hyperopia is found among diverging strabismus, viz., 28.6$. These are mostly of moderate,degree, each eye usually had good vision, and the cause was found in weakness of the interni. In some cases this ensued after the occurrence of debilitating diseases, in other cases the weakness was inherent and original. Another class of cases is those in which one eye is so nearly blind that it wanders outward simply in obedience to the tendency impressed upon it by the outward direction of the axis of the orbit. Here, too, there may be latent weakness of the interni. Divergent, begins at a later period of life than convergent squint—when the latter is connected with myopia it is usually of high degree. It may be alternating, but usually the patient gives the preference to one eye. Very often there is marked irregularity in vision or in refrac- tion. The tendency of myopia to divergence is caused by the high degree of convergence required for near vision and by the absence of impulse to accommodation to aid it—a situation which is the exact reverse of what obtains in converging strabismus with hyperme- tropia. In both classes of cases there must coexist a lack of power in either the externi or the interni to render the deformity possible, while refractive conditions play a role which has been sufficiently explained. Treatment.—In the incipient stage of converging strabismus we may sometimes prevent its establishment by employing the glasses needful for correcting ametropia. Serious amblyopia will be a hinderance to success and when the subjects are very young there are obvious objections to their use from the danger of acci- dents by breakage. But when in the house, young children can wear spectacles and, when at active out-door play there is less ten- dency to close convergence. It has been proposed to use eserine sulphate to assist the accommodation (Ulrich) and take off strain on the interni and to resort to this when glasses cannot be worn. On the other hand, the entire suspension of accommodation by atropia has been much recommended and employed from precisely the opposite indication, viz., to relieve the interni by abolishing the accommodation. A degree of benefit can be gained by this pro- ceeding, but no permanent gain without using the needful correcting glasses. The resort to atropine from time to time as the tendency to squint becomes more pronounced, while the patient is habitually wearing correcting glasses will not seldom prevent the establish- ment of the error. It is decidedly worthy of trial because the externi are strengthened and the habit of binocular vision is pro- moted. When this is not feasible, and a patient shows a decided tendency to prefer one eye in fixation—this may for some hours daily be tied up (screening it by a shade will not serve the purpose) STRABISMUS CONCOMITANS. is; in order to compel the use of the other. By so doing the muscles of that eye are kept in better training, although the covered eye continues to squint. The use of the poorer eye to improve its vision is a pious hope rather than an assured expectation—notwithstand- ing the contrary opinion largely prevails. Any other treatment than tenotom}' is of little value after a permanent squint has been produced. In diverging strabismus, associated with myopia, the greatest assistance is to be derived from proper concave glasses, to be em- ployed both for near and distant work. They should be chosen with reference to the degree of myopia and to the accommodation of the subject and to the distance of the working point. Very often they will be one-half or one-third less strong than the glasses required for the far-point. The rules for this have already been discussed. The use of glasses by young myopic persons includes this very important advantage, that control over the recti interni is greatly aided. This suggestion is also applicable to cases of great dissimilarity in the degree of mj^opia of the two eyes even when one of them may not admit of the glass which its refraction indicates, and the correction is applied only to the better eye. Atropine has less efficacy in these cases than in those previously considered. In incipient divergence not only are glasses to correct ametropia important, but they can often be usefully combined with prisms. Whatever relieves the strain on the interni at the near- point, is to be adopted. The subjects are usually old enough to permit a satisfactory examination, which with convergent squint is often impossible. In the large majority of cases of convergence and in many of divergence we must resort to an operation. The operative treatment has in view not only the correction of deformity, but the improvement of the working ability of the e3Tes, and if possible the procurement of binocular vision. We practise tenotomy upon the contracted muscle to abate its power and we advance the insertion of the weaker muscle to increase its power. The former is the most frequently employed, while the latter is in certain cases combined with it. A practical question arises in con- verging squint, how early in life shall tenotomy be practised ? If the deformity is not large it is better not to operate until five to seven years of age. But if the squint be pronounced, a tenotomy at an earlier age may be indicated to keep the muscles in better balance, but its effect will not be complete and it should not be done except as a palliative measure. At a latter period another operation is likely to be needful. Should one eye be operated on or both ? Graefe taught the importance of dividing the effect between both eyes, but since his time some have advocated going back to the practice of early times and confining the proceeding to the eye 188 DISEASES OF THE EYE. which deviates most. As a matter of fact, in marked deviations the muscles of both eyes are at fault and I have no hesitation in say- ing that each eye should in such cases be operated on. For a devia- tion of 3 to 5 mm., 5° to 15°, only one eye is to be operated on; for 5 to 6 mm., 15° to 30°, both will require it, but there should be two weeks interval before the second operation; for squint of 10 mm., 30° to 45°, both may be dealt with at the same sitting. It may be assumed that one tenotomy will effect a change of about 3 mm., or about 15°. An absolute result cannot be predicted because the elasticity of the opponent is variable, and we find the ultimate position frequently not the same as that which appeared after the first week. Inas- much as the patients especially seek an improvement in their personal appearance, the rule is to leave a slight degree of conver- gence rather than to risk the slightest amount of divergence. If there be fairly good vision in both eyes and if there be hyperopia of 3 D or more, we may put considerable confidence in the tendency of the eyes to a correct position. In such cases the effort is to establish binocular vision, and if there be a divergence of 1 or 2 mm. this will usually not be permanent. It is not, however, to be as- sumed that a free dissection of the tendon is to be allowed. This was the method at the first introduction of strabotoniy by Dieffen- bach, and from the unwise practice of that day came a large crop of cases who needed a subsequent and serious operation to correct the divergence. Such cases are occasionally met with at the present time. The operation is as follows: For young subjects ether may have to be given, for older ones instillation of 4$ solution of salicylate or hydrochlorate of cocaine three times within twenty minutes will suitably benumb the tissues. The local anaesthetic is much to be preferred, because we need the aid of the patient to enable us to decide how much has been accomplished. The lids are separated by the spring speculum; for converging squint the eye is pushed to the outer angle by a fixation forceps which seizes the conjunctiva near the outer border of the cornea and if the forceps be rather heavy it may be left to hang and its weight will keep the eye in position. Employ forceps with a stiff spring whose teeth project well forward, take up the conjunctiva and tendon at the latter's insertion and snip it with slender scissors whose points are a little rounded. The wound must be small and vertical and at the middle of the tendon. If an opening has been made through the tendon the slender scissors may be slipped astride the lower and upper portions of the tendon in succession and accomplish most of the cutting. The rest of the insertion may be caught up by the hooks and divided. If the tendon has not been opened, the forceps will be thrust through the conjunctival opening to seize it and be followed by the scissors. The sharp projecting teeth are designed for this STRABISMUS CONCOMITANS. 189 purpose (see Fig. 78). Snip through the tendon and passing through the hole a small blunt hook catch the upper half of the insertion. Keep the scissors flat on the sclera and cut at the insertion. Keep hold of the tissues by the hook and insert a second hook under the undivided lower half of the tendon and cut it. Then examine above and below whether the whole insertion has been separated from the sclera. The cutting is partly subconjunctival and partly visible in the wound. A little oarb on the blunt point of the hooks materially facilitates the search for undivided fibres and gives greater hold to the hook (Theobald) (see *""> Fig. 77). The conjunctival wound will unavoid- ably be stretched by these manoeuvres, and some blood will be effused beneath the tissues. It is a disadvantage to have a large thrombus because it increases the effect and renders the operation less certain. In putting the hook under the tendon carry the beak straight back and keep the tip upon the sclera as it is rotated either upward or downward. When it is well engaged the handle is carried across the root of the nose and the tendon pushed into view. Now the tendon is cut between the hook and the sclera and of course it is not shortened, but is only detached. There are other methods of operating. Some make the incision of the conjunctiva below and parallel to the edge of the muscle. Graefe ad- vised making it close to the cornea. Arlt uses scissors alone to divide the muscle without the help of the hook. For myself the method de- scribed secures the complete division of the ten- don with the least disturbance of the structures and through the smallest wounds. The conjunctival wound is always united by a stitch of very fine black silk. The bleeding is to be wiped away with absorbent cotton. Sponges are objectionable unless very fine and soaked in corrosive sublimate solution 1: 2,000. It is better to use salicylated absorbent cotton. Before putting in the stitch the effect of the operation is to be ascertained. The associated movements should be well performed, and if the de- sired effect is apparently reached, the patient should be able to converge easil.y to a point five inches distant. If sufficient effect is not secured, incisions may be made above and below the insertion into the capsule of Tenon. To dissect the con- junctiva more freely away from the outer surface of the muscle by undermining the caruncle will also increase the effect, but at the expense of an unpleasant retraction of the caruncle. 190 DISEASES OF THE EYE. Another mode of increasing the effect is to gather up a fold of the conjunctiva on the other side of the globe in a large suture (Knapp). Better than this, is to attach a suture to the con- junctiva on the outer side of the globe near the cornea and carry both ends through the skin beyond the outer canthus and tie them over a bit of stick. Such a guy will put the globe into any desired position. The thread must not be left more than five or six hours and both eyes must be well bandaged to prevent pain. I have seldom resorted to these sutures. To restrain the operative effect, a stitch may be carried to a greater or less depth into the divided muscle and brought out near the cornea horizontally, or in an oblique direction. A change of 2 mm. is easily obtained. In rare cases when I have sought to slightly increase the effect and the conjunctival wound has been small I have altogether omitted the suture. To do this, is to risk undesirable retraction of the caruncle and the sprouting of granulations in the wound. Sinking of the caruncle is liable to occur in slight degree even after operations carefully done. It comes as a gradual result of con- traction of the cicatricial connective tissue, and depends upon the de- gree to which the oculo-orbital fascia has been invaded and loosened. It is always proper to lay upon the usually squinting eye the larger effect of the operation. If the deviation is chiefly monolat- eral, one may combine tenotomy of the internus with advancement of the externus of the same eye. If this do not suffice, tenotomy of the internus of the other eye may be done at a later time. The advisability of advancement may be estimated by the capacity of the eye to turn toward the outer canthus. In marked monolateral squint this will be feeble and the externus will have been so. much stretched that it cannot pull the eye around even when the internus is loosened. In one case of this kind where one eye had slight myopia and the other an extreme degree, notwithstanding a good position of the axes was obtained, it could only be held by wearing full cor- recting glasses and practising daily with prisms for three months. Wecker has recently advocated what he calls advancement of Ten- on's capsule at the insertion of the antagonist, as an adjuvant to tenotomy. The operation consists in bringing forward the inclos- ing sheath and connective tissue as one would do in certain modes of advancement of the tendon (see chapter on Asthenopia), but the tendon is not loosened. A well and neatly conducted advancement seems to me is to be preferred. As a matter of fact the chief ele- ment in tenotomy as well as in advancement, is the altered tension and attachments of the sheath and capsule—combined with loosen- ing the insertion of the muscle. The ultimate result of an operation is apt to be greater than that which exists after two or three weeks. STRABISMUS CONCOMITANS. 191 For ordinary cases very simple after treatment suffices, the eyes are bandaged for twelve hours and then cold or warm water applied as the patient prefers. The conjunctival stitch may be taken out in two days or, if left to itself, it will drop out in a week and it causes no appreciable irritation. Subconjunctival ecchymo- sis will remain for ten days. If granulation spring up, it must be cut off with scissors, not touched with caustic. For diverging strabismus the mode of operating is essentially the same, but the tendon of the externus is 7 to 8 mm. from the cornea, while that of the internus is 6 mm. The effect of the tenotomy is usually adequate in simple cases of myopia, but in em- metropia and hyperopia it is less than ordina^. Advancement of one or both interni may be advisable in extreme cases, or a tenot- omy may be done the second time. For a young lady on whom I had done two tenotomies of each external rectus without a perfect cure, the result was obtained b}r causing her to practise daily with adductive prisms to the utmost of her ability. She had good vision, and was emmetropic in each eye. She gradually improved in power of adduction and on one occasion felt something snap in one eye, after which she acquired a sufficient power of convergence and has always retained it. A suggestion of Dr. Gruening has proved of great value in considerable degrees of divergence when no paralysis exists. After dividing one or both externi, the two e3^es are coupled together by a suture which is attached to the inner side of the globe and carried across the nose. It takes its hold on the conjunctiva vertically near the cornea, and when tied, both eyes are held im- movable and in convergence. It is left in situ for twelve or twenty- four hours. Care must be used to get no more effect than is re- quired. An excess of 10° or 15° convergence at the beginning is desirable, for this amount soon disappears. With extreme diver- gence Dr. G. shortens the tendons of the externi. Hardly less important than a correct operation is the subse- quent management of the eyes. As soon as the reaction has dis- appeared, say within four to six days, the propriety of using glasses must be decided. If there be much hyperopia and the externi are weak, not only should glasses be worn, but possibly it will be needful to resort to atropine. In other cases only the manifest H will need correction. If there be tendency to over-effect, then no glasses are to be given. Of course, astigmatism is to be corrected. Sometimes practice with prisms and a candle flame, or the use of the stereoscope will aid in confirming correct attitude of the eyes. Very many patients can be made to see two images after an operation who found the great- est difficulty in doing it before, and they can be taught to closely approximate or to fuse them. Special test cards must be provided for practice with the stereoscope, viz.: on one side a vertical and on 192 DISEASES OF THE EYE. the other a horizontal line, or on one side a dot and on the other dots in horizontal series which are to be numbered, or on one side a capital L and on the other a capital F, which combined make E (Green) or other similar devices by which it will be certain that each eye sees and takes a correct position. With the usual stereoscopic pictures there can be little assurance that proper vision is being practised. Of course such exercises require intelligence, the subject must not be too young and vision must have a certain acuity. Javal employs an ingenious reflecting stereoscope which admits of variation in the angle of reflection and consequently of conver- gence. Mechanism of the Operation and its Ultimate Results.—There is a notable lack of accurate and well ascertained information on this subject. With patients the object sought is cosmetic, and if a passable result is obtained they are content and likewise too often is the surgeon. It has been claimed that decided improvement of vision is procured by the operation and aiso that binocular vision is a result frequently secured; v. Graefe and Knapp claim 50$. A good cosmetic result is rarely difficult of attainment, by combina- tion of methods and by sometimes doing a series of operations. In cases of decidedly monolateral converging squint with great weakness of the externus and also in cases of divergent squint, where one eye has turned aside simply because of extreme defect of sight, both retirement of one tendon by tenotomy and advance- ment of the opponent is required. Such is also apt to be the case with divergence ensuing from marked debility of the interni in cases of E and H notwithstanding vision of each eye may be good. Here, as already said, simple tenotomy is apt not to suffice but must be combined with advancement. With ordinary convergence cos- metic success is secured by carefully avoiding unnecessary disturb- ance of the surroundings of the tendon, whether lateral or between it and the conjunctiva, and by not attempting to secure too much by one operation, whether upon one or upon two muscles. It must never be forgotten that the mechanism of the proceeding consists in letting the tendon slip back and take a new attachment to the globe behind its original insertion. For the degree of retirement which may be safely permitted we must take into account the length of the internus and the degree to which it is shortened. Its length including the tendon is about 40 mm. With a squint of 5 mm. it is reduced to 35 mm. when in the squinting position. The externus has a normal length of 49 mm. and this will be stretched to 54 mm. The internus in the normal position of the eye lies in contact with the globe for about 7 mm. This is of course shortened in the squinting position, by the degree to which the eye turns in- ward. Where the insertion is displaced backward, the muscle at STRABISMUS CONCOMITANS. 193 its new hold still has a favorable position for action because this point is now turned outward and will permit the muscle to exert its force in a tangential direction. Evidently, however, if the in- sertion be pushed back beyond a certain extent, the action of the muscle becomes more and more embarrassed. Every tenotomy signifies a limitation in the mobility of the globe—this may within certain limits, in the case of antagonist muscles which have not become seriously degenerated, amount simply to a displacement of the arc of rotation. But in very many cases the arc of rotation is shortened, because the externus is incapable of carrying the eye outward to the degree by which the arc has been diminished on the inner side. In this statement lies the reason for the rule, that it is proper to let the muscles have time to adjust themselves to the new relations, provided one operation fails to procure the desired effect. The occurrence of relapses is also thus understood if it be found that the externi prove to be too feeble to maintain the advan- tage which tenotomy has given them. At the same time the abso- lute unwisdom (to use a mild phrase) of striving by free dissection to effect the purpose before a suitable adjustment of the muscular forces has been secured, is obvious. No surgeon, however careful, can claim absolutely immunity from the liability to slight over-ef- fect in some cases, because it is impossible to control or acquaint ourselves with all the conditions of the problem. Divergence, amounting to 3 mm. or more when looking at a distance, is to be deplored, and such a degree of deformity reflects discredit upon the surgeon. The value of the operation consists in improved appearance, in more comfort in using eyes, in enlarged binocular field, in the inci- dental correction by glasses of refractive errors, sometimes normal binocular vision is gained. That it permanently improves visual acuity is seldom true. An exceptionally good and permanent restoration of sight is given by Johnson, Trans. Am. Oph. Soc., 1893. In discussing this point we must choose patients whose age and intelligence enable them to give us trustworthy information. I have at hand the records of forty operations of which thirty-six were for strabismus conv. and four for strabismus div. Twenty- three patients who had convergence I regard as capable of giving reliable information—their ages are as follows: From 6 to 10 years = 6 « n " 15 " =5 " 16 " 20 " =5 " 21 " 42 " = 7—23 From these, eight cases are taken out who had V = f£ or §£ in each eye both before and after the operation, some of them requiring 13 194 DISEASES OF THE EYE. correcting glasses. In the remaining fifteen cases before the opera- tion, vision in the poor eye was from -£& to yfo. In three cases the ophthalmoscope showed defects which would necessarily prevent visual improvement. In the thirteen which are left, five showed absolutely no improvement in visual acuity. We are reduced then to seven which are fairly proper for investigating and testing the point. 1. A physician, aet. forty, had compound hyperopic astig- matism in the poor eye; when corrected vision improved from $fo to £■#, but the operation had no share in the benefit. 2. A young lady, aet. sixteen, had astigmatism in both eyes; when corrected the poor eye had V = f#. Six months after the operation, having been subjected to the use of atropine and having used glasses, and hav- ing also covered the good eye for certain periods so as to compel employment of the other, the vision of the poor eye remained f-g, and without a glass was T2^. 3. Young lady, ast. fourteen, before the operation the poor eye with + 3 D counted figures at three feet, after the operation counted figures at six feet. 4. Young lady, ast. seventeen, the' poorer eye had with -f 1.5 D V = f{ and there was hemiopic amblyopia, but this vision six months later was -^\. 5. Male, aet. nine, in the poorer eye with + 6.s O — 0.75c 180° V = f#. ]3y tenotomy and optical treatment binocular vision was obtained, but in both eyes the vision remained the same for fourteen months. G. Male, aet. eleven, with -f- 2.s V = f# before operation; after ten- otomy and use of atropine and glasses with -4- 3.s V = f-§-. Binocu- lar vision was obtained, but no betterment of acuity was procured in the faulty eye. Numerous specks were visible about the macula. 7. Male aet. twenty-two, in poor eye V = -f (|. Had an operation on both eyes ten years before I saw him. I did tenotomy on one and obtained binocular vision, which was known to remain for four months, but no improvement in acuity ensued in the amblyopic eye. These few cases do not justify a broad generalization, but they correspond to my much more extended observations, and in the conclusion to which they point, my opinion is in accord with Schweigger's. It remains to consider how often we obtain binocu- lar vision. On this point experience has taught me that the num- ber of well-tested cases in which this can be proved, provided we demand the same kind of binocular vision of which normal eyes are capable, is excessively small. I have not gathered large statistics, but out of the small number of records at this moment at my disposition, viz.: thirty-six cases 6f convergence operated on, only four gained binocular vision, which is 11$. Out of the thirty- six there were ten who had in each eye better vision than f #, of those only one gained binocular vision. Of the three others who secured it, the poor eye in all had V = £#. It does not need large STRABISMUS CONCOMITANS. 195 statistics to show that if among ten patients in whom each eye has . nearly normal sight and who by tenotomy and optical treatment \ are put in a position to acquire binocular vision, nine fail to do it, that there lies behind the ocular conditions, a something which con- stitutes an insurmountable obstacle. This is indeed the fact, and to it Hansen and Krenchel have especially called attention. It is the lack of that cerebral co-ordinating faculty which is the essence of binocular fusion. It would appear that when this faculty is once lost or perhaps has never been developed, it can rarely be acquired after the very early years of life. I do not assert that in only 11$ of all cases can binocular vision be obtained. I have not studied all my records, but I am certain that the number is less than 20$. That a certain kind of co-ordination can occur between two previ- ously strabismic eyes, which do not each direct its macula upon the object must be admitted. It is often possible after an operation to elicit double images when it was before not feasible. But this is a factitious and not genuine binocular vision. One who argues on these points must explain what kind of vision he claims to exist. A valuable kind of binocular vision exists in persons who have a high degree of anisometropia and in whom it is impossible for the images to be similar and who in reading will use only one eye. This occurs in persons who have had one eye operated on for cataract; while this gives sharp vision they cannot dispense with the assistance which the other unoperated and imperfectly cataractous eye gives them for purposes of general vision. This vision is really binocular. Yet there also arise cases of squint where vision is performed by one eye at the macula and by the other at a point many degrees aside from the macula. These persons will sometimes be found to have acquired a kind of binocular sight in which dissimilar parts of the two retinae have learned to become associated. This kind of retinal incongruity does sometimes exist, and is not within the scope of our usual physiological explanation. In conclusion I strongly urge the importance of exactness in the performance of the requisite operations and of care and persever- ance in the subsequent optical treatment to secure the best result. The reaction after tenotomy is usually slight. In only three or four instances out of several hundred have I seen important in- flammation occur, and this soon subsided. Once after tenotomy of both interni diphtheritic inflammation attacked the wpunds, the patient having been allowed to go home. The eyes were saved, but excessive divergence eventuated. The operation for advancement has been discussed under the head of Strabismus paralyticus. The treatment of periodic or as it may be termed incipient stra- bismus by selection of correcting glasses and persistence in using them will not infrequently cure the deformity and also bring about 196 DISEASES OF THE EYE. binocular vision. This point has obvious practical importance and its verity is proven by my records. Intermittent strabismus is extremely rare. A case reported by Dr. Harlan in the Transactions of the American Ophthalmological Society, 1881, p. 277, may be referred to. A child three years old exhibited concomitant convergent squint every other day for one year, and it usually came, on awaking from sleep and would last during the day. It passed over into permanent squint. The re- fraction was emmetropic as decided by the ophthalmoscope. Nothing is said of the degree of vision or of the possibility of diplo- pia. When the strabismus was fully established it varied from time to time within very wide limits. It was under observation four years. Strabismus Deorsum Vergens, or Sursum Vergens, is to be treated by operating on the rectus inferior, or on the rectus superior. The obliqui are not suitable for interference. Landolt has devised a method of tenotomy for the inferior oblique; but the occasions for it are extremely rare. It has lately been stated (Eperon1) that advancement of the weak muscle is to be preferred to tenotomy of the deflecting muscle. I think favorably of this statement, knowing that ten- otomy of superior or inferior rectus is not as certain in results as of the external or internal rectus. Both proceedings may some- times be combined. Paralysis of superior oblique is best remedied by dividing the rectus inferior of the opposite eye, and subsequently, if needful, dividing the rectus internus of the affected eye and later the in- ternus of the fellow-eye (Alfred Graefe). Each case will have its special features and careful estimate of the conditions will be demanded. Knapp has reported cases. It is to be remembered that division of the superior rectus acts by association on the levator palpebrae superioris, and is followed, not only by a depression of the globe, but by lifting of the upper lid, by which an unusual amount of sclera will be exposed above the cor- nea. This fact may be utilized, if there be partial ptosis, both to aid the levator of the lid as well as the depressor of the globe. Correct vision below the horizon is of much greater value than above it. For strabismus convergens or divergens, with upward or downward deviation, it is proper to cut the adjacent tissues rather freely on that side of the vertical meridian to which the eye most deviates. 1 Arch. d. Ophthal., March, April, 1889, p. 115. Condensed in Ophthalmia Review, July, 1889, p. 205. CHAPTER X. ASTHENOPIA. This term and its synonyms, hebetudo visus, kopiopia,painful vision, express the fact that exertion of the eyes is wearisome or pain- ful, and there are often besides ocular, other symptoms, viz., head- ache, pain in the back, nausea, dizziness, as well as numerous remote disturbances. The term is convenient, but not definite. To give to it positive character, we must discover the error or condition on which it depends. The following subdivisions are clinically separable. As- thenopia from: 1,refractive errors, causing overtaxed accommoda- tion; 2, from muscular errors; 3, from neurasthenia. To these has been added 4, asthenopia as a reflex effect from the nasal mucous membrane, from which arises often a decided and unusual degree of conjunctival irritation, and was noted by Schweigger. I have long recognized an intimate relation between nasal catarrh and chronic conjunctivitis, and that with it asthenopic symptoms are frequent. In a somewhat similar sense there are asthenopic symptoms with incipient cataract, with progressive myopia, with early presbyopia, but such cases need no consideration under this head. Neither is there need to refer to cases of pure neuralgia of twigs of the fifth nerve: the supra-orbital is most frequently at fault, and from malaria. Hyperaesthesia retinae has been set down as a kind of asthenopia, but it is commonly only one of its symptoms, and has for its cause some of the conditions above mentioned. Accommodative asthenopia need not detain us long. It is the subjective side of various refractive errors, such as hyperopia, astig- matism, anisometropia, etc. Upon this Donders laid special stress and thus set apart an important class of cases. If they have any typical subjective symptom, it is likely to be indistinctness of vision after prolonged work on near objects. Besides the blur of print, there will be pain in the eyes, and especially headache, either frontal or temporal or general; there may be dizziness, nausea, and other remote symptoms. In investigating etiology we may meet large refractive errors, but it must be emphasized that in susceptible persons small errors, especially hyperopic astigmatism calling for a cylinder with axis nearly vertical, or even small degrees of hyperopia, demand exact 198 DISEASES OF THE EYE. correction. As a fact we have often to deal with a susceptible organ- ism, and because it is easily set ajar, we must remove even minute sources of disquietude. For this reason we are called upon to use atropia very often for such subjects. They may have notable photophobia, and this at the beginning may be aggravated by myd- riasis, but perseverance until all spasmodic and painful accom- modation is abolished will also remove photophobia. It sometimes happens among these subjects, that atropia causes headache, and it may be very severe. If the case, as will in rare instances occur, be one of merely feeble power of accommodation, useful local treatment is to drop sol. muriate of pilocarpine, gr. ij. ad oz. i., into the eye once daily; or, sol. sulphate of eserine, gr. -J ad oz. i. But general tonics and rest of the eyes will be the chief reliance. These cases may have other complications, and there are thera- peutic suggestions to be made which will be referred to hereafter. It is important at this point to discuss the properties and uses of prisms before entering upon the subject of the conditions for whose detection and relief they are employed, viz., errors of the ocular muscles. Their physical properties are extremely simple. A prism is a transparent substance in- cluded between two plane surfaces inclined to each other. The thin edge or angle is called the apex, the thick border is the base ; a line drawn from the Fig. ra apex perpendicularly to the base is called the base-apex line. The position of a prism may be described by referring either to its apex or its base, but by custom we usually choose the base and say that the base is placed in one direction or another relatively to the eyes. Refraction through prisms is shown in Fig. 79. On the surface AC of a prism let fall a ray HK; it is deflected toward the perpendicular at K, emerges at D, is there deflected away from the perpendicular to 0. The apex of the prism is A, its base is CB. The deflection of light is always toward the base. The rays which impinge at oblique angles are deflected more than those which strike ver- tically to the plane of incidence. Hence the so-called minimum deviation implies that rays fall vertically. Beyond a certain obliquity of incidence rays cannot escape from a prism, but undergo total reflection from the in- terior and opposite surface. The angle of total reflection varies with the refractive index. For spectacle glass (crown 1.53) it is 40° 49'. Except for purposes of examination only prisms of low angles (below 10°) are used in ophthalmic practice. There is no focus and they form no image. They de- ASTHENOPIA. 199 compose light into its elements, and this property of "dispersion" gives them their value in spectrum analysis and is their disadvantage in physio- logical optics. They produce colored fringes on the edges of objects by this " chromatic aberration.1' Objects viewed through a prism are seen in a false position; for example 0' 0 Fig. 80. an object at 0 seen through the prism appears to be situated at another spot, viz., O'. The stronger the angle of the prism the greater the displace- ment, and for prisms of low angles the " deviating angle " is half the angle of the prism. The displacement of the object is always toward the apex. If a prism be placed before each eye and the base of each be to the right the Fig. 81. object will be displaced to the left, but the visual lines will not be altered in their angular relation. If, however, the prisms be placed with their bases the one to the right and the other to the left, or "outward," the object viewed by the right eye will be displaced to the left, and that viewed by the 200 DISEASES OF THE EYE. left eye to the right, and diplopia (crossed) would ensue if the visual lines did not turn toward each other in convergence. Hence prisms with bases outward are called adducting. If now the bases be turned toward the median line the opposite effect follows—the object is displaced outward and again would diplopia (homonymous) occur, did not the visual lines make a corresponding divergence. Hence prisms with bases inward are termed ab- ducting. If in Fig. 81 with prisms bases outward the eyes view the object 0, the displacement for each will be toward the median line and double images will appear projected for L to the right of O and for R to the left of 0, i.e., crossed until the visual lines have converged so as to make the two images at their intersection at 0' unite into one image. The effect is an ap- parent approximation of the object, its reduction in size, and a conscious converging effort accompanied by accommodation. Now reverse the prisms, as in Fig. 82. Let the object be nearer, say at O. The displacement is for each eye outward, and homonymous diplopia occurs until the visual lines diverge far enough to intersect at the point O'. The effect is an apparent removal of the object and a conscious relaxation of con- vergence and accommodation. Still other effects occur which will be re- Fig. 82. ferred to later. The extent to which convergence is possible greatly exceeds the possible divergence. If in the above experiments the object be at G metres or at 20 feet dis- tance (the visual lines practically parallel), they may by adductive prisms be forced into extreme convergence and by abductive prisms into a moderate amount of divergence. It has been said that for spectacles only weak prisms are used, and that for them the deviating angle is about one-half the refracting angle. The de- mand for accuracy in ophthalmic methods has led to suggestions for a more ASTHENOPIA. 201 perfect system of notation. The reason is that as found in the shops prisms seldom conform precisely to the number marked as their angle, and it is also desired to make prisms conform to the principle now universal with other glasses, of numbering them by their power and not by a purely optical prop- erty, and in doing this to establish a simple and uniform ratio among them. Dr. Jackson proposed to number them by their deviating power in angles and to mark this number on the prism, using the letter d after the number, e.g., for a prism of 4° angle, 2°d ; of 2° angle, l°d. See Trans. Am. Oph. Soc, 1888, p. 150. Dr. Dennett proposes a new method based on a very modern conception in physics, the radian, which is an arc whose length equals its radius of curvature, viz., 57.295°, of which he would take the hun- dredth part, the centrad. For special description see Trans. Am. Oph. Soc, 1889, and comments on it by Dr. Burnett, Ophthalmic Review, January, 1891. An optician, Mr. Prentice (Arch, of Ophth., xix., Jan., 1890, April and July, 1890), has brought forward a nomenclature which is certainly simple, accurate, and in accord with our customary practice with other glasses. He proposes to measure prisms by their displacing effect measured on a plane (tangent) at 1 metre distant from the prism, and the unit to be a prism which shall at this distance cause a displacement of 1 centimetre. It happens very remarkably and fortunately that the prism of 1° and index 1.53 causes this quantity of displacement within a negligible fraction. This unit he calls the prism dioptry, PD. The value of any prism can be easily found by drawing upon a card placed at a convenient distance, say 6 metres, a series of parallel lines 6 centimetres apart, and looking through the prism to be examined, the number of spaces and fractions which a long line or a candle flame is dis- placed, denotes the number of the prism. Mr. Prentice remarks that the average deflection of our commercial prisms from 1° to 5° corresponds very closely to this scale up to the fifth division. It therefore follows that the terms are almost convertible, and our old nomenclature by degrees, differs little from prism dioptries. The following table gives the differences (taken from De Schweinitz): Prism Dioptries PD. 1. 2.0001 3.0013 4.0028 5.0045 6.0063 7.0115 Refracting Angle of Prism Required. 1.06° 2.16 3.24 4.32 5.40 6.47 7.54 Prism Dioptries PD. Refracting Angle of Prism Required. 8.0172 8.62 9.0244 9.68 10.0333 10.73 15.114 16.1 20.270 21.13 42.288 39.0073 Prism dioptries are easily convertible into metric angles (see p. 188). By assuming the average adult interpupillary distance at 64 mm., one MA = 32 mm. deviation, which is about one-third of one PD (i.e., 100 mm.). Therefore 1 PD = £ MA; or 1 MA = 3 PD; or 4 MA = 12 PD, or a prism 12.89° angle. Another point for consideration is the prismatic effect of decentering lenses. Mr. Prentice has shown that a lens decentered one centimetre gives a pris- matic deviation of as many dioptries as there are dioptries in the lens. A lens _|_ 4 d decentered one centimetre gives a displacement of 4 PD, and if decentered one-half a centimetre a displacement of 2 PD. Moreover, DISEASES OF THE EYE. the centrad of Dr. Dennett and the prism dioptry are almost identical. It thus appears that the decentration of strong lenses is an important cir- cumstance, while for lenses less than 2D the deviations are small and seldom important, except by extreme amounts of decentration. For example, a 2 D lens must be decentered one centimetre, or j", to get the effect of a prism of 2°. A table elaborated to millimetres is given by Maddox, "Clinical Use of Prisms, etc.," Win. Wood & Co., Medical and Surgical Monographs, vol. ix., No. 2, Feb., 1891, p. 291. We shall permit ourselves to speak in the old nomenclature of designating prisms by their angles, because for those with which we shall chiefly deal the errors are small. Moreover, in muscular asthenopia not only do we use weak prisms, but their effect in a physiological sense is far higher than their optical values would suggest. Muscular Asthenopia ; Muscular Insufficiency ; Dynamic Squint. To the subject of muscular insufficiency and more particularly of the internal recti in myopic eyes, von Graefe was the first to call attention. See Arch. f. Ophth., viii., Abth. 11, 314,1861. He did not omit to mention its existence under other refractive conditions, but since his time the field of inquiry has greatly widened. We always take account of the refractive state, but while myopia undoubtedly carries with it many and serious conditions of muscular trouble, this fault is exceedingly common both in other forms of ametropia and in emmetropia. We have to do chiefly with disturbances of adduc- tion and abduction, while a small number of cases exhibit errors in the movements upward and downward. We have referred to the intimate relation which subsists between accommodation and con- vergence, and we know how greatly this is modified by the refrac- tion. Attention has been chiefly directed to muscular errors as they are developed at the working point, and it is here that the chief strain occurs, but it is found that their study at the far-point is more often of controlling importance. If the working point, as in myopia or amblyopia, be very close, the high angle of conver- gence aggravates the strain in rapidly increasing ratio. What- ever be the degree of adductive effort, it is needful to have a cer- tain amount in reserve, and it is also needful to possess a sufficient, abductive capacity to balance adduction. Landolt declares that there must be converging power in reserve twice as great as that which is being employed, but this fails to, take account of cases where defect of abductive power leaves ad- duction almost unchecked. We employ prisms in measuring adduction and abduction, but another method has been introduced by Nagel, which has been adopted by Landolt ASTHENOPIA. 203 and to some extent by others, and which, because it is scientifically accurate, may be explained. It is founded upon a unit called by Nagel the metre angle, which is analogous to the metre-lens or the dioptry, which was also introduced by Nagel. The metre-angle is the angle formed at one metre distance by the inter- section of the visual line with the median plane. In Fig. 83, let the inter-ocular dis- tance be represented by the base line EE. Let M be the centre and draw the line MH. Let EA represent the optic axis of the left eye when looking at a distance. It is then parallel to the median plane MH. Now let the eye E fix upon an object distant one metre and draw EM' equal to one metre. The angle AEM' is the deflection of the optic axis to the median line for the dis- tance of one metre. This is the metric an- gle or angle of deflection or adduction for one metre. Let another point be taken calling for an additional and equal deflec- tion ; this will intersect the median line at M"; add a third equal angle of deflection and we meet the median plane at the point M'". The distance from M' to infinity is one metric angle, from M" to infinity is 2 metric angles, and from M'" is 3 metric angles. The effort of accommodation to M'" is 3 D ; to M" is 2 D ; to M' is 1 D. We see a perfect coincidence in the ex- pression for the two functions. The metric angle is manifestly larger when the base line is longer, i.e., when the inter-ocular distance is greater. This dis- tance we measure between the centres of the pupils, or, more correctly, between the centres of rotation of the globes. Nagel gives a table of the value of the metric an: gle for various inter-ocular distances going from 50 mm. to 75 mm. In children the dis- tance may be assumed to be on an average 58 mm., and in adults 64 mm. For the former the metre-angle will be 1° 39', 99', or say 100'; for adults it will be 1° 50'or 110' (minutes). In measuring prac- tically we may employ an arrangement of Landolfs, viz., a metric tape line upon which metre-angles are marked, one end of which is held to the temple and the other end is attached to a little lantern inclosing a candle and which is the object of fixation. The lantern has a hole in the side and the patient holds it as close to the eye as he can without seeing it double; this point read off on the tape gives the number of angles of convergence. To measure what can be done in divergence beyond parallel visual lines, prisms with the bases inward are required. To translate the finding of prisms into metric angles we insert a table from Prentice (Arch. of Ophth., xix., 1, 1890), where the sine, tangent, and 204 DISEASES OF THE EYE. angle are accepted as equal, showing the value of the angle of convergence when the interpupillary distance is taken at 64 mm. Metric Angles. Dioptries, PD. Degrees of Arc, Sine. 1 3.2 1'50' 2 6.4 3 40 3 9.6 5 30 4 12.8 7 20 5 16. 9 10 10 32. 18 20 20 64. 36 40 In this table the error up to 5 metric angles is unimportant, and we need not concern ourselves about higher degrees of disturbance, because for such cases prisms are never applicable. But for persons whose interpupillary dis- tance is other than 64 mm. we need a rule for determining the metric angle and the corresponding prisms. Prentice gives the rule: " Read the inter- pupillary distance in centimetres, when half of it will indicate the prism dioptries required to substitute one metre-angle for each eye." For 60 mm. the base line is 30 mm., and the metric angle will be 3 PD. For 50 mm. the base line is 25 mm. and the MA = 2.5 PD. A reference back to p. 201 will give the actual angular equivalents of the prisms. If now we add the number of metric angles for the near, to those obtained at a distance, we get the total so-called amplitude of convergence; which may be put into formulae precisely as we discuss dioptries of accommodation. Before discussing erroneous conditions we must have some standard of the normal status of the muscular apparatus. The total lack of binocular vision has been referred to under paralysis and strabismus; we now consider the conditions under which its maintenance is difficult. It has been shown that in all persons there exists a considerable power of forcing the visual lines beyond the point of binocular fixation, and that the possession of a certain surplus power is necessary to comfortable vision. If we fix on a small gas flame at 20 feet distance, we can preserve single vision, even though prisms with bases outward be interposed amounting to from 30° to 50°. We can also see a single flame if prisms with bases inward amounting to from 6° to 12° be interposed. In these performances the adducting and abducting muscles are forced to unusual effort, and the limit of their capacity is denoted by the prisms, which finally bring on uncontrollable double sight—we see two flames. In doing this we look forward on the median plane, and the effect consists in forced contraction of all ocular muscles with predominating effort of certain groups. We may say very broadly, admitting numerous exceptions, that normal adduction is 25° to 45° and normal abduction 6° to 8°. Abduc- tion is more nearly constant than adduction. This may be ex- pressed in metric angles if one please, but the facts are not altered. Deviations from the horizontal plane are physiologically more re- ASTHENOPIA 205 stricted; we can seldom do more than overcome a prism of 2° or 3° with base either upward or downward. If the head is turned laterally and the eyes are directed obliquely at the flame the co- ordination of the muscles is changed and the findings with "eyes front" will no longer hold good; both adduction and abduction will change and in diverse ways, not yet much investigated. If now we attempt to determine the total adductive power we must not only bring an object close to the face but often resort to prisms with bases out to ascertain the totality. Many persons can squint inward to excess and beyond measure. It is of little value to learn the amount of this ability, and we therefore attempt to discover what flexibility, so to speak, there may be in the mus- cular power when we are at the ordinary working distance. This, may be at from 6 to 20 inches according to the state of refraction and the habit and age of the person. But if we make proper cor- rection by glasses, and if we permit certain persons to choose special distances according to their requirements, we may for the large multitude assume 13" or one third of a metre as a conven- ient point for measurement, because it closely approximates 16", the usual distance of reading, writing, sewing, etc. We have now in use 3 dioptries of accommodation and 3 metric angles of convergence, which may be represented by 9.6° PD for the average adult inter- pupillary distance of C4 mm. Each eye is inclined toward the me- dian plane a quantity represented by a prism of about 10° angle, making a total of 20° for both eyes. What additional amount of adduction will now be possible? Here again wre find great varia- tions. It will reach from 10° to 50°. As to abduction, we would naturally count on at least 20° to establish parallelism of the visual lines, but we must remember that an accommodative effort of 3D is being maintained, and that this hinders the free use of the abduc- tive capacity. We find that the range is from 10° to 20°. For the punctum agendi the average capacity is: Adduction, 20° to 40°; abduction, 15° to 20°. We have at 13" even less freedom in vertical planes than we have at a remote point. In the above statements it is seen that we cannot apply the pre- cise rules to which we are accustomed in refractive problems to the conditions now discussed, and for obvious reasons. The very essence of the organs is mobility and variable energy. To Graefe we owe a very ingenious device to attempt to discover what are the conditions of dynamic repose of the two eyes. Creating uncontrol- lable diplopia by a prism with its base-apex line vertical, he con- ceived that the eyes would adjust themselves to the status of re- pose and reveal either a normal or abnormal condition. Experience has proven the untrust worthiness of this test as a single reliance, but it does create a condition which gives valuable hints. Graefe's 206 DISEASES OF THE EYE. large dot and fine vertical line are better substituted by a small white dot on a black card at 13", while the vertical prism test requires for its distant object the same small flame at 20 feet. Under these tests the normal and usual results are for 20' a position of the flames varying not more than 1° or 2° either way from the perpen- dicular, and for 13" it is most common to have 5° of divergence from a perpendicular. As already said, the statements now made about the usual be- havior and capacity of the ocular muscles under the tests de- scribed must be taken as very general, and subject to very numer- ous exceptions. The departures from the status described are often very startling. General Divisions and Considerations.—We are testing what is called the " capacity for fusion " of the separate retinal images. This is a cerebral function; it is capable of cultivation, it depends on a variety of factors. Some of them are, 1st, approximate equality in the refraction and perceptive function of the two eyes, or, in other words, the absence of high refractive errors or of marked defects in visual acuity. For these reasons cases of anisome- tropia, of muscular amblyopia, of loss or defect of sight in one eye, of decided myopia in each eye, of hyperopia, of visual obtuseness, always predispose to or present notable variations from a normal standard of fusion. Again, 2d, we find actual muscular anomalies, in spasm of certain muscles, or in weakness of muscles which may be due to faulty insertion, or to lack of muscular fibre. 3d. Doubt- less variations in the density and arrangement of the oculo- orbital fascia give rise to greater or less degrees of effective- ness in the muscular contractions, because it holds them steady and makes an auxiliary insertion for their tendons. Especially is this true of the recti. The importance of this fibrous membrane has been too little considered both as a causative factor and in operations. 4th. The complexity of action of the twelve muscles concerned, the necessity for rapid, exact, and smooth performance, and that during waking hours or the maintenance of the visual act, they are perpetuall}' on duty, and that their combinations must be adjusted to such variable distances, angles, and cover so wide a field, and that the mental consciousness relies so absolutely and instinctively on their work in its judgments respecting the external world—these considerations make it clear that their function is important, and that we ought to expect the same variations in their conduct which we are not surprised to find in what we call the temperament, the constitution, the idiosyncrasy of different individuals. 5th. We are brought by the last statement to consider the condition which more than all others is the presiding factor in muscular asthenopia. This is somewhat difficult to express, but may be called the quality ASTHENOPIA. 207 ■of nerve energy. The health of the efferent nerves, of their nuclei in the medulla oblongata, and of those portions of the cortex, with which they are associated, in fine the vigor and quality of the whole nervous system enter into the problem. This con- sideration explains why in some persons large muscular anoma- lies have little or no disturbing influence and in other persons small errors are most harassing. This explains why asthenopic symp- toms appear after attacks of sickness, during debilitating condi- tions, as the consequence of grief, of shock, of worry, as the accom- paniment of many chronic diseases having no direct connection with eyes or brain. 6th. Overwork and inadequate nutrition bring about muscular asthenopia. On this point we do not dwell. Lastly, if we have not catalogued all the conditions which account for the presence or absence of symptoms of muscular asthenopia, it is clear that among those mentioned numerous combinations of local and general causes can take place which will give rise to startling and perplexing and distressing situations. The judicious and skilful treatment of cases of muscular asthenopia with all the complica- tions which may co-exist is the highest problem in ophthalmology. We divide cases of muscular asthenopia into two broad classes, and these together make a third, which is naturally the largest. We have the myotic and the neurotic. Under the myotic are in- cluded those in which muscular anomalies are the great and pre- dominating factor; the neurotic are such as exhibit such anoma- lies, but their influence is made potential by the dominating neu- rotic condition. In the first class, refractive errors may play a, part by inducing muscular disturbances, and their elimination often completely removes the muscular troubles; in other words, the correction of astigmatism, of hyperopia, of anisometropia, will often leave no occasion for dealing with muscular faults be- cause the strain on the muscles disappears. (It is pertinent to say that these errors express their hurtful influence through disturb- ances of a muscle, viz., the ciliary, and the intimate association of this with the motor muscles makes the concurrence natural.) On the other hand, a minority of cases of refractive error do not find relief by focalizing glasses, but demand substantial aid for com- plaining muscles in addition. These may furthermore be compli- cated by neurotic conditions which must have full recognition, or treatment will not, and perhaps cannot, bring relief. Furthermore, numerous cases present themselves in whom the manifestly conspicuous feature is the neurotic disturbance; it may be excitability or intensity of action, or exhaustion from any cause. In these cases muscular defects are common, either in a greatly reduced power of fusion, feeble muscularity in all directions, or in spasm of convergence, or in the hurtful effect of minor errors 208 DISEASES OF THE EYE. whether of one sort or another. It is of course frequent to find small refractive errors, and how marvellous may be the benefit gained by their correction, has been already noticed. It is here that the potency of the .25 D is observed. It is also among these people, mostly women, that the very weak prisms find their utility. To such a point (a vanishing point) has this prescription been carried, that a paper has been written on the value of the prism .25 P. D. Modern civilization, the exigencies and urgencies of so- cial and business life, hereditary tendencies, and the American temperament with its stimulation of the mental faculties makes neurotic asthenopia in its various phases a disease widely prev- alent in our community. How this general tendency in some cases reacts upon the retina will be mentioned later. These general statements will, I trust, make it clear that my standpoint in viewing a case of muscular asthenopia is to regard the general condition of the patient as the controlling circumstance,, and deal with the ocular conditions in subordination to that. I hold firmly to the necessity of rigid, complete, and exhaustive investiga- tion of all refractive, muscular, and other functional errors, and apply the proper correction, but the purpose is to include these particulars in a judicious estimate of what relates to general health and temperament and surroundings. A corollary to this statement is that while with neurotic people small errors must receive un- usual consideration, one must not forget with them the influence of mental impressions, and the cures wrought by suggestion, hyp- notism, metallotherapy, electricity, etc. We may now particu- larize some of the usual exciting causes. We have to note over- taxation by reading on railway trains and in carriages; by reading when lying down, which convalescents and chronic invalids often find out too late; by attempting difficult work, such as embroidery, sewing on black, fine painting, decoration on china, etc.; bending over the work and bringing it too near the eyes; by the study of languages whose text is intricate, such as Greek, German, Hebrew, etc. Want of vigor, whether by congenital conditions of health, by too rapid growth, by malaria, by any debilitating causes, by shock, grief, etc., are to be duly considered; especially all forms of uterine disease, hemorrhage, fevers, chronic anaemia, instigate muscular asthenopia. It will often happen that the depressing agencies mentioned, are simply exciting causes of a disorder whose real progenitor is an essential muscular weakness, which may long have been latent, but is now made potential. Some cases seem to have congestion at the base of the brain and there is tenderness over the middle and upper cervical verte- brae. Nasal catarrh is both a complication and a cause, while the same is true of chronic conjunctivitis of the lids and blepharitis. ASTHENOPIA. 209 Subjective Symptoms.—Pain in using or fixing the eyes is the conspicuous symptom. This appears in all kinds of near work, reading, writing, etc.; it may also exist in distant vision, in look- ing at a crowd, or at the stage in a theatre, looking out of a car- riage or from the window of a railway car, etc. There may be great photophobia. Seldom is there blur of sight, while unsteadi- ness of letters or work, which is caused by a tendency to diplopia, resembles the blur of refractive error, and is sometimes thus spoken of. The pain is generally in the eyeballs and inclines the patient to press on them for relief; but it is often temporal, fron- tal, occipital, or at the vertex. In truth, not a small percentage of obstinate headaches, especially " sick headaches," originate in dis- orders of ocular muscles. A frequent symptom, and one not easy of explanation, is headache on first waking from sleep in the morn- ing. Sometimes dizziness occurs. When the general health is fee- ble, or the subject neurotic, we may have the most erratic and intense remote symptoms: aphonia, palpitations of the heart, pain in the ovaries, diarrhoea, rectal irritation, etc. Asthenopia in some subjects is almost as protean as hysteria, and the two go hand in hand. It has been asserted that chorea is caused by this condition, but my observation has been that usually the order is otherwise, and that it is chorea which gives rise to debility and irregular action of ocular muscles as one of its manifestations. Epilepsy has been asserted to depend on this cause. I cannot deny that, in a few cases, eye strain may have been demonstrated to be an exciting cause or occasion, but there has been behind it a deeper lesion of the general nervous system. This statement is quite consistent with the disappearance of epileptic fits in case the mus- cular eye trouble is cured. Well-marked relief in a case of epilepsy took place in the practice of Dr. Ranney of which I had personal knowledge. The great relief, effected by tenotomies, was only partially maintained afterward, but the health improved and the frequency of the fits was much reduced as late as three years after the operations were begun. For further discussion on this point see Report of Committee.1 Objective Symptoms.—These are as follows: while both eyes within certain limits seem to move in harmony, for certain extreme positions to the right or left, or up or down, the}* become tremu- lous or one will deviate; in the median line and at moderate dis- tances there may seem to be no fault, but if an object be brought very close to the nose a deviation may occur. If no evidence is 'Journal of Nervous and Mental Disease, Nov., 1889, p. 657. On the sub- ject of the general disturbances of the nervous system due to ocular derange- ments see Anstie, "Neuralgia." 1872, p. 169, the writings of Weir Mitchell, and " Functional Nervous Diseases,-' Stevens, New York, 1887. 14 210 DISEASES OF THE EYE. thus obtained, repeat the same experiments, bidding the patient regard the finger as it is carried to various extreme positions, and while he fixes upon it, put a card before one eye and note whether, when binocular sight is thus abolished, the covered eye may not deviate from its correct position. Especially useful is this test when searching for weakness of adductive muscles, the finger being brought within a few inches of the nose, and each eye alter- nately covered by the card. There are other ways of determining the so-called static condition of the eyes, but they only give hints and not measurements. The parallax test (Duane) is one, which shows a deviation in fixation by the difference in localizing the gas flame with each eye alternately, the other being screened. Within a few years much has been written, in this country especially, on tests for muscular errors, and various refinements have been brought forward by Duane, N. Y. Medical Journal, Aug. 3, 1889; by Stevens, the stenopaic spherical lens, Ophthalmic Record, vol. i., 7 and 8, 1892, Nashville, Tenn.; by Maddox, the rod test, and the double prism test. Several instruments have been invented, viz., the phorometer, by Stevens; an apparatus by Ris- ley, Med. and Surg. Reporter, Phil., Dec. 5, 1891; an apparatus by Gradle of Chicago, and other contrivances. Long practice in using simple contrivances and the habit of searching repeatedly and with much care have enabled me to accomplish so much that I have not cared to be cumbered with elaborate apparatus. The necessary appliances for my work are squared prisms about 1£ inches long on the side and varying from £° to 15° and some twenty in number; prisms mounted in series or piles, two sets, one having even numbers from |° to 20°, the other having odd numbers from 1° to 21°; a combination of prisms 5,° 15°, 10°; prisms mounted in spectacle frames of low degrees, 1° to 3°, with bases in or out; a Maddox rod mounted, a square double prism (Maddox), a disc of red glass. These serve for the examination at 20 feet. For the working distance I employ a simple prism holder shown in Fig. 86, which serves likewise for detecting spasm of accommodation, and will permit the use of correcting glasses as well. The test for the near ought never to be omitted. I discard instruments like the revolving double prism of Cretes because they tempt the patient to put forth efforts which are only temporary and misleading to the oculist. Hence in the piles of prisms the intervals are 2°, so as to learn more correctly what the patient can do. To keep the square prisms level is very easy, and I avoid in an examination the use of trial frames, or of anything placed on the face until high de- grees of prisms are reached. The argument on behalf of Stevens' phorometer, that by being placed several inches from the patient it removes the liability to cause stimulation of muscular errors, in ASTHENOPIA. 211 my experience is not well founded. The phorometer is widely used, is a good piece of mechanism, but its tendency seems to me to be to develop and exaggerate small errors which are unimportant. I need not remark that refractive errors are corrected by suit- able glasses, and sometimes atropia is used. If refractive error be above 2 D the correction is always interposed; if less than 2 D I am not careful about it, because large and careful investigation has shown that small errors seldom make impor- tant modification of the muscle findings. In all muscular tests a red glass before one eye ex- aggerates the conditions observed, by diminish- ing the tendency to fusion. The first test object will be the small gas flame at 20 feet, against a dark background. For errors of the oblique muscles a heavy black line, one foot long, on a white card is useful. A small gas jet may be put at the middle of a Fig. 84. Fig. 85. card on which are lines drawn parallel and 6 centimetres apart, and the card made to revolve, to permit comparison of the dis- placement caused at different positions of the prism. The patient stands, the test box is at his right, the observer faces the box and the patient; he holds before the left eye a 5° or 8° prism with base upward; vertical diplopia ensues, which perhaps the patient does not immediately notice—the flame seen by the left eye is projected below. If the two images are not plumb, the pile of prisms (Fig. 85) is brought before the right eye with base on the side where the top image is said to stand, and moved up until the images are made plumb. A. red glass will develop the error to a 212 DISEASES OF THE EYE. greater degree, whatever its character. Maddox' glass rod held horizontally before the left eye gives rise to a vertical (or perhaps oblique) streak of light on the level of the true flame, which it may intersect or lie either to the left (convergence), or to the right (di- vergence). The double prism of Maddox (advantageously modi- fied by Savage) consists of two prisms, each of 4°, placed base to base, and the patient looks through them at their junction. One eye (always the left, unless this is highly amblyopic) sees two displaced images and between them the true flame. These three flames are to be brought in line by the pile of prisms above men- tioned. The test now made has decided value, but it does not measure anything precise or which has commanding importance; it is merely one factor among many. To speak of this finding as the measure of the so-called insufficiency is to fall into error. There is no exact measure of " insufficiency," and the term is one of general significance, not of precise notation. The next test is to measure the degree of abduction. Hold in one hand a square prism of 5°, base inward, and if the light re- mains single put a prism pile before the other eye with base in- ward, until the extreme capacity for fusion is found. If the light become double, turn the base of the prism pile outward and re- duce the effect of the 5° prism until the correct result is obtained. At this stage another use may be made of the abductive prisms. Place before one eye a prism of 10°, base in, and if this be not enough to excite diplopia, add 5° or 10° to the fellow eye. Hold the prisms horizontal and inquire if the double images are on the same level; if not, there is a tendency to vertical error (hyperphoria). It is not at all rare to find small errors. If we rotate the patient's head on a vertical axis, the sidelong fixation will many times bring out vertical error. So common is this experience as to be almost physiological. The reason is, that in a movement to the left, for example, the left eye easily preserves the vertical meridian vertical, but the right eye under the influence of the superior and inferior recti as sinistral rotators must be exactly balanced by the superior and inferior oblique to keep its vertical meridian vertical, and this implies an equilibrium of forces very likely not possible. It must be remembered that the strong prisms have abolished the instinct for fusion, and the test object (the gas light) is so small as not to furnish such an inducement to fusion as would a larger one or as would a rod or line. In discovering vertical errors it is of the utmost value to make the patient move the head back- ward and forward as well as sidewise, while the prism induces ho- monymous images; the evidence is the fact that at certain positions there is a greater or less amount of displacement than in other ASTHENOPIA. 213 positions. An additional proceeding is to hold a 5° prism base up before one eye and then place it before the other, or reverse it be- fore the same eye. If there be a notable discrepancy in the separa- tion of the images, this marks hyperphoria. It will be noted that none of these experiments stimulate a tendency to vertical move- ment; they simply elicit the tendency to want of parallelism of the visual lines in the vertical plane. The measure of the amount is made by placing before one e3Te a prism with base toward the image, until a level is established. This prism will vary from £° to 3° or 5°, while I have corrected a case of 17° vertical error. In this kind of measurement (for hyperphoria) the phorometer of Dr. Stevens is exceedingly con- venient and accurate. As to the practical value of the measure- ment, comment will be made hereafter. The next step is measurement of the adductive power. We expect this to equal 25° to 60°. Most people will show less than 30° Fig. 86. until educated to more. The compound prism, Fig. 84, may be held in the left hand with the base out. Employ the 5° next the 10° and before the other eye place one of the piles and carry it up to its maximum ; then put the 15° before the left and again run through the pile until its bottom prism is reached, or until the patient "balks" and declares that he cannot unite the images. One must coax and urge and persuade and "chaff" the patient to do his best and never lose patience, and be ready to try, try again. If the adducting faculty is higher than 32° put on a pair of square prisms, each 10°, in spectacle frames, and begin again as before. It is a useful check test in some cases to try the adduction in side- long positions as well as with eyes front; it will always be lower in amount, and sometimes extraordinarily. It is proper to make mention at this point of the nomenclature for latent muscular errors (called by Graefe dynamic squint) invented by Dr. Gr. T. Stevens (Arch, of Ophthal., XVI., No. 2, 149. 1887), and which has gained ex- tensive currency. The terms are convenient as general designations. But 214 DISEASES OF THE EYE. the excessive elaboration which has been proposed, and the intensely sym- bolic writing which some have employed like a cipher code, mystifies and obscures the facts. I. Generic Terms. Orthophoria: a tending of the visual lines to parallel- ism ; heterophoria: a tending of these lines in some other way. II. Specific Terms. Heterophoria may be divided into: (1) esophoria: a tending of the lines inward; (2) exophoria: a tending of the lines outward ; (3) hyperphoria: a tending of the right or left visual line above its fellow. This term does not imply that the line to which it is referred is too high, but that it is higher than the other, without indicating which may be at fault. III. Compound Terms. Tendencies in oblique directions may be expressed, as hyperesophoria: a tending upward and inward; or hyperexophoria: a tending upward and outward. The designation " right" or " left " must be applied to these terms. We next examine the same functions at the patient's working distance, and to do this I have long found it convenient to use a holder which consists of a central stem about 0.5 metre long, gradu- ated in inches or centimetres and metric angles, on which is a slider carrying test cards, and which contains three cells before each eye into which corrective glasses and squared prisms may be dropped (see Fig. 86). It will contain prisms amounting to 50°, and is more convenient than the trial frame. If, as sometimes happens, a pa- tient cannot put forth his real energy when lookipg into an appara- tus, let him make a few trials without it, holding the test card in the hand. We usually begin with Graefe's so-called equilibrium test, employing a prism of 10° with base vertical. He used a large dot upon a very fine perpendicular line; I use a white dot upon a black card as less liable to stimulate efforts of fusion. Some use fine letters. It is most common to find that the images do not stand vertical to each other, but that there is a deviation in the sense of divergence of about 5°; this cannot be called abnormal. More than this must be noted. A deviation in the sense of con- vergence is always abnormal, and directs suspicion upon the ex- terni. Next try the abduction and the adduction by prisms suitably placed. It is best to begin with abduction. Often a patient will show only 6° or 8°, because of involuntary convergence; hold the finger between him and the test card and bid him follow it down to 13"; he gets single vision of the finger, and as this drops out of sight the dot is single. Add another prism, say 2°, and shift the prisms from one side to the other so as to make the increments small, usually by 2° or 3° at a time. Gradual coaxing will bring the abduction to its maximum. This device is extremely important in the numerous cases where vertical diplopia at 13" displays marked esophoria, Another trick is to push the slider half-way up to the face and gradually withdraw it. It is absolutely necessary to give the patient every possible chance to exhibit all the abduction he possesses. In trying to find all the adductive power, we cannot do ASTHENOPIA. 215 so much to aid the patient as for abduction; nevertheless pushing up* the slider and slowly withdrawing it will often help him do his best. In assuming 13" as the proving distance, allowance must be made for high refractive errors, especially myopia, and the distance may be modified to the requirements of the case. It is also obvious that the glass needed for the working distance must be provided; this applies to presbyopia as well as to all refractive errors. It will to many be a surprise to learn how low is the adductive power with presbj^opic correction, and in how few instances inconvenience is felt. On the other hand the displacement of the relative accom- modation explains the annoyance caused by using too strong glasses for presbyopia, and sometimes, when the glass is weak. It is true, as is now generally recognized, that our findings at the working point are subordinate in importance to the conditions elicited at 20', but they have no little significance in the general estimate which we make. Very often the indications corroborate the diagnosis of spasm of convergence in the strongest way, or they teach us that we have to do with overtaxed and incapable muscles for which rest and improved general energy are most necessary. The prescription of prisms or of tenotomy on the basis of what tests at 13" show is seldom advantageous, or even per- missible. In cases where marked esophoria shows excessive convergence for the whole range of fusion, we must look closely for spasni of accommodation. Often in these cases there is mild li3Tperopia or astigmatism, or both; we want to know if the}^ alone condition the muscular disturbance. Before using atropine, or even if it has been used and we want to find out if its work has been fully achieved, we may resort to a test on which I have relied for approxima tely accurate results for twenty years. I slip into the holder a pair of spherical prisms 4-3DC prisms 6° bases inward. An emmetrope ought theoretically to read S. 1 (the very fine capital letters N P r T v) at 13" with -f- 3 D. But this will only be true with monocular vision and with relaxed interni, conditions seldom presented in the consulting room; hence we must cause relaxation of the interni by interposing abductive prisms. The convex glass and the prism com- bine to the same result. As a fact, with such a glass (an approxi- mation to Briicke's dissecting spectacles) the point of fusion of the visual lines for the average inter-ocular distance of 64 mm. is not far from 2 M. A. In reality, as the conditions are various in dif- ferent persons, the intersection of the visual lines is at 4' to 6' dis- tance, while the accommodation is at 13". Some enlargement of the image is caused by the glass. Reading S. 1 at 12" is not to be regarded with suspicion, but when the point must be pushed to 10" 216 DISEASES OF THE EYE. or 8" we have to diagnosticate spasm or amblyopia, and act accord- ingly. If vision be feasible at 11£" to 13" we need not be concerned about atropine unless other evidence compels it, such as the oph- thalmoscope, the shadow test, etc. An indication of vertical error may often be found by the tip- ping of a patient's head; he carries it bent to the shoulder and perhaps a little rotated. Close inspection will often show asym- metry of the head and face—one ear will be higher than the other; the floors of the orbits are not horizontal; the cranium will be lop- sided. In such cases, which are common enough, one will usually find hyperphoria, and sometimes, but by no means always, will it demand correction. Observations of this character have been recorded for many years among my notes. So decided are my convictions on this matter that I may cite instances of evident paresis of the superior oblique muscle examined and treated more than twenty years ago in which the best results were gained not by correcting the difference of the images in height, but on the working and the horizontal plane. The writer is himself an in- stance of the innocuousness of a vertical error when it develops itself 15° above the horizon; this he has from traumatic paresis of right obliquus inferior (see Trans. Am. Oph. Soc, 1877). It must, moreover, be emphasized that examinations at the working point should be made not on a horizontal but on a plane 15° below the horizon, for this is the physiological primary position of fixation (Aubert, G. and S.). It cannot, however, be denied that cases exist in which hyperphoria throws other sets of muscles into spasm and irregular action, giving incongruous findings with prisms, and re lief is only gained upon removal of the discord in the muscles of elevation or depression (see Stevens, 1. c, p. 165), It may be well to remark here upon a special symptom seen rarely and in severe neurasthenic cases, viz., retinal anaesthesia. It consists in limitation of the visual field, rarely in hemianopsia, and still more rarely in general reduction of light perception. There are no abnormal appearances with the ophthalmoscope. Wilbrand1 called attention to it, and Priestley Smith2 has related cases. If the visual field be examined by the perimeter more than once, the field will be found smaller on each successive trial, and Priestley Smith therefore refers to this as a spiral limitation, and* calls it a reflex amblyopia due to an impoverished state of the blood, and excitation of the vaso-motor nerves causing arterial contraction. I have ob- served a few cases, and clinically they differ from migraine in being caused by fatigue of the eyes. See case by Stewart.3 1 Archives of Ophthalm., xii., 428, 1884. 2 Ophthalmic Review, vol. hi., p. 140, 1884. 3 American Journal of Ophthal, Vol. 7, 184, Julv. 1888. ASTHENOPIA. 217 Asthenopia associated with disorders of the nasal cavity deserves special mention—the connection between chronic palpebral conjunctivitis and nasal catarrh has been referred to, and for a long time it has been the occasion in my own practice for treating nasal catarrh to cure the palpebral disease. With- in a few years several authors have written upon it (see Nieden1), but some- thing less simple and obvious sometimes appears in the phenomena of pro- nounced asthenopia. To these cases Nieden refers in a brief paragraph (1. c, p. 419), and a very marked instance recently occurred in the person of a medi- cal friend, which may be briefly described. Dr. T. E. S., aged 44, a hard-working and distinguished practitioner of New York, given to microscopy and book making, found his eyes give out in 1886. He consulted a competent oculist, who gave him various glasses with incom- plete success. He went away for a vacation and under advice of another able oculist be underwent the use of atropia for five weeks, and received a modified formula for glasses: viz., O.D. + 1.25s DC-i-0.25cD 90° visusf^; O.S. + 1.25c D 3 + 0.50c 90° visus f|}. A note by the physician also stated that there was want of energy in the internal recti muscles, and excessive power in the supe- rior rectus of the left; that headaches were due to excessive strain of accom- modation. He wore glasses in accordance with the above formula with the addition of a prism 1° base down for O. S. For reading + 0.75 D was added to the above. His distressing symptoms had continued two years.-consisting of pains in the head, heat at the vertex, insomnia, inability to use his eyes and the effort would be followed by facial neuralgia. He had intense photopho- bia and had worn dark blue glasses for months. He had had much mental strain outside of his professional work, and his case was evidently a complex of local eye troubles, with retractive and muscular and general nerve exhaus- tion. A marked symptom was extreme palpebral congestion, and tendency to lachrymation on exposure to light and attempting eye work. So pre-emi- nent was this feature that I was led to inquire into the condition of the nasal cavity. I found the passages narrow with slight protuberance of the sep- tum from undue thickening, decided congestion, tenderness on being touched, and anaesthesia by cocaine afforded relief in some measure to the eye symp- toms. Careful examination of refractive and muscular conditions showed that at 18 adduction = 15c, abduction = 7°; the ophthalmometer gave astigmatism,O.D. 1.50 D 75" ± 165°; O.S. 1.25 D 90° ± 180V It was evident from the variability of his answers to the muscular and refractive tests that there was much spasm both of the extrinsic and ciliary muscles. Guided by his previous treatment and the present symptoms, I determined to attack the nasal disease and made several applications of spray. Relief was experienced, and on hearing that he suffered from asthmatic attacks, that his breathing at night was much embar- rassed and must be done with open mouth, I determined to enlarge the nasal aperture, both to get rid of a hypersensitive surface and to afford more air space. I removed a projection of the septum on the left side with the saw. Marked improvement quickly took place. He took horseback exercise with enjoy- ment ; within a month reported that he " felt young and frisky.'' The glasses were slightly modified—the photophobia soon abated and practically disap- peared. Muscular spasm ceased, all headache and neuralgia vanished. Within four months he laid aside glasses, was restored to comfort, and is 1 Arch, of Ophth , vol. xvi., No. 4, 1-SST, p. 416. 2 The si.M DISEASES OF THE EYE. a weak convex glass, or a weak prism 2° or 3° for each eye, with base inward, is given. Each day the period of reading is increased by one minute or by two minutes, and the most scrupulous exact- ness is insisted on. In place of reading, other work may be substi- tuted, but the great matter is to regulate and systematize the eye work. Combined with this proceeding, the galvanic battery, either the constant or interrupted current for a few minutes, with one pole to the closed eyes and one pole on the temple, has some, yet small, value. Stimulating liniments to the forehead and temples of aconite, or of chloral and camphor, etc., are useful when there is neuralgia. The douche or spray of cold water, or mild lotions to the eyes, viz., borax and camphor-water, are all helpful. In some cases, notwithstanding refractive errors are slight, it is best to pre- scribe the wearing of glasses, especially if convex or cylindric, all the time. The behavior of the muscles, both with and without the glasses, will help to decide this point. Another mode of invigorating the eye-muscles, and which is especially suited to the cases where all the muscles are feeble, is by using prisms as means of gymnastic training. Dyer's method deals with muscular action and accommodation together; by gymnastic prisms the extrinsic muscles alone are acted upon. The patient is provided with prisms of 2£°, 5°, two of 10°, and one of 15°, with squared outlines. He takes a candle-flame or door-knob at twenty feet for his object, and performs the efforts of adduction and abduc- tion by means of these prisms. He begins, say with adduction, and at first holds the prism of 5° with base out, in front of one eye, then substitutes the 10°, then before the other eye, places 5°, making a total of 15°; then, if practicable, substitutes the other prism of 10° for the 5°, and so climbs up the ladder of adductive prisms l\y such steps as he can make. If the interval of 5° becomes too great, he may take that of 2^°. On the other hand, he will in a similar way train the abductive muscles by putting before one eye with its base inward, the prism of 2^°, then that of 5°, then one before each eye, and finally, may possibly reach the 10°. To reach an adductive power of 42|° and an abductive power of 10° will require sometimes several weeks, and when attained should be practised once or twice daily. The daily session need not occupy more than ten minutes, and need not be more frequent than twice. There are few cases to which this method is well suited, and one need not spend much time over it. Improvement in adduction is often gained, but sel- dom in abduction. Some special disharmony will usually be dis- covered. Sometimes it will be preferable for the physician to superintend the prism practice, both for its beneficial effect and to elucidate the diagnosis. If muscular defect be combined with important refractive error, ASTHENOPIA. 221 we have most frequently myopia with insufficiency of the interni, which may be relieved either, 1st, by wearing the full optical cor- rection continually; or, 2d, by using for near work a glass which pushes out the near-point to 8", to 12", or to 14", and which may be of about half the power of the full correction; or, 3d, with the glass just mentioned a prism may be combined, or the glasses may perhaps be given an adequate prismatic quality by having them set in the frame with their centres outside the visual lines. This brings the inner thick edge of the glass into use, whereby it will have a low prismatic effect. For the rare cases of myopia with in- sufficiency of the externi, optical corrections alone are not often available. With hyperopia similar methods of proceeding may be adopted, but with such adjustment of prisms as the kind of muscu- lar error calls for. With emmetropia one finds less certainty in the helpfulness of prisms to aid the performance of near work. They sometimes are utterly intolerable, even with decided muscular error. In deciding how strong the prisms are to be, we first decide the proper working distance, and the correcting-glass, which for this point is required, and with it ascertain the muscular error. To give prisms equal to one-half the amount of error is usually suffi- cient. If we estimate the insufficiency at say 10°, we may order the prisms each 3°, one before each eye. It is only when error is decidedly more on one eye than on the other that the prisms are made unequal. But for quantities so large, tenotomy is preferable. The cases of muscular asthenopia without any or any important refractive error are much more frequent than has been supposed. By far the largest quota present insufficiency of the external recti. To these cases my attention has been pointedly called within a few 37ears;1 and they become in my experience more and more con- spicuous. They are recognized by the tests at a distance rather than by those for the near. To form some idea of the refractive conditions in muscular asthenopia, one hundred consecutive cases for which prisms were deemed suitable are quoted. They are taken from my series of records of muscular error noted from C 826 to C 969, in all 144 cases. The 44 rejected were either not counted suitable for prisms or were not observed long enough to be valuable; some were purely neurotic cases, some exhibited weakness of all the ocular muscles, and some were operative cases. Emmetropia including those with H not exceeding + 0.50 D = 52; H from .75 D to 2.75 D = 24; Ash from + 0.75 D to + 2.00 D = 3; mixed astig. 4.50 = 1. Total, 100. Of the 24 cases of H, 11 were of 0.75 D, giving 63 cases in which 1 See paper "On the Tests for Muscular Asthenopia, and on Insufficiency of the External Recti Muscles." Trans, of Eighth Session of the Interna- tional Medical Congress, Copenhagen, 1884, 222 DISEASES OF THE EYE. the amount of II was insignificant and was certainly not the im- portant factor. Alongside of these may be placed 11 cases of Ash of + 0.75 D, although in them more stress is to be laid upon the re- fractive error than for simple H. Astigmatism of all kinds claims 21 cases; and myopia 3. A further interest attaches to the kind of muscular error, and herein my views published in 1884, and quoted in the 1st edition of this text-book, p. 201,1890, are fully cor- roborated by additional experience. Insufficiency of recti externi = 73; insufficiency of recti interni = 26; vertical error = 1; total = 100. The similarity of results is remarkable because in 1884 I found 74$ of recti externi, and in 1892 I find 73$ of the same. A further analysis giving the refractive conditions under the separate types of muscular error shows the following: Insuf. externi, E error not exceeding +.50 36 H 19 M 2 Ash 13 Asm 2 Antimetropia 1 73 Emmetropia, hyperopia, and hyperopic astigmatism include 68 cases, and while the refractive error was in most cases corrected, this alone did not give relief. It is quite admissible to suppose that spasm of the interni is more at fault than defect of the externi, and this is doubtless the true pathogenesis of most cases, and that the weakness of externi is secondary. The result of treatment in the abandonment of prisms after a certain time, often demonstrates this to be true. It might in some cases, perhaps, have been pos- sible to break the morbid chain by prescribing atropine for three to six weeks, but cui bono ? Prisms meet the indications. Insuf. interni, E error not exceeding + 0.50 16 H 5 Ash 4 Asm 1 26 Among these cases spasm is necessarily excluded, and they fur- nish a sufficient answer to the objection made against my views of these cases, that they represent simply minor degrees of uncor- rected hyperopic error rather than real muscular faults. Among them emmetropia and hyperopia and hyperopic astigmatism ASTHENOPIA. 223 count for 25$. I need not press the logical value of these cases; they eliminate all that might be urged in opposition on the ground of personal bias. To complete the cases there was one of vertical error—giving this form of trouble (hyperphoria) the ver}7 modest showing of 1$. It is right to add that among the 44 rejected cases were 6 in which vertical error was noted, making out of 144 cases of all kinds of muscular trouble almost 5$ of this type. It is common to find that wearing prisms a little while increases the manifest amount of muscular weakness. I speak particularly of the externi, in other words the abductive power is less. The explanation simply is that the overtasked muscles give up the struggle and lean on the glasses. Hence it frequently follows that prisms are a prelude to tenotomy. This comes about when pain returns, in spite of prisms. I once increased the angle of adductive prisms for weak externi up to 7° for each eye in obedience to the demands of a patient, who refused tenotomy,'but for whom it was finally done with most brilliant result. That prisms so weak as 1|° are capable of producing positive and bene- ficial effects is not only attested abundantly by experience, but a sufficient reason is found in the degree of convergence which they induce. Instead of parallelism we have an abatement of one-half a metric angle for the inter- ocular distance of 60 mm. And this is in reality one-sixth of the effort re- quired at the assumed working point of \ metre or 3 metric angles. A con- stant abatement of abduction amounting to 16$ of this requirement is certainly not insignificant. If there be insufficiency of the interni for distance, we may uni- formly expect the same at the working point. It may, however, not exist at the remote end, and exist at the proximal end of the binocular visual line. On the other hand, insufficiency of the ex- terni may occur at the distal end and be greater at the proximal, or it may change to insufficiency of the interni. We may some- times properly give prisms of different degrees for the respective positions, but we ought not to give adductive prisms for distance and abductive for near, until the full benefit of the former has been developed by wearing them many weeks. It may also be remarked that weak convex glasses sometimes take the place of adductive prisms for near work, but not often in subjects with vigorous ac- commodation. My conclusion from ample experience is strongly in favor of the helpfulness of weak prisms continuously worn, for moderate degrees of muscular error, and they have in my practice largely taken the place of Dyer's method, of gymnastic prisms and of the various palliative proceedings above referred to. In giving prisms the rule may be formulated that the base should be placed toward the image whose position is to be cor- rected, and this corresponds to the weak muscle, provided the phy- 224 DISEASES OF THE EYE. siological or functional action of the muscle is regarded. The apex of the prism like a knife edge indicates the muscle which should be weakened and the base denotes the muscle to be strengthened. The resort to operation is next to be discussed. It was em- ployed by French surgeons,1 Bonnet, Guerin, Cunier, so long ago as 1841 for the cases now under consideration, but intelligent adapta- tion of it was first proposed by v. Graefe2 in 1869. He especially de- veloped its employment for deficient adduction in myopia. We have learned by large and ofttimes deplorable experience that very great discrimination must be used when we employ surgical means for a functional muscular error. We must clearly recognize the distinction already indicated between cases purely muscular, and cases where muscular errors are symptomatic of nervous dis- turbances. These latter are of obscure pathology and a simple mechanical correction may utterly fail of relief. It may be tem- porary or partial, or it may issue in diplopia excessively distress- ing, or in aggravation of previous sufferings. It is very difficult to formulate rules for these cases, because we meet with such diverse conditions. The operations may have uncertain results, and must alwaj'S be done without general anaesthesia; happily cocaine renders this entirely feasible. The effect must be measured immediately by prisms, and be controlled at least as soon as the following day, because it may be in excess or deficient. Generally complete tenotomy has been done; by some partial tenotomy has been em- ployed (Alfred Graefe, Abadie, etc.), while Stevens employs " grad- uated tenotomy," which seems to be almost a full tenotomy, 1. c, p. 173; but he also seems to practise frequent partial tenotomies at intervals of weeks or months, until the desired result is achieved. With complete tenotomy the effect depends upon the extent to which the oculo-orbital fascia is loosened (capsule of Tenon), and this tissue varies much in density in different persons. As supple- mentary to tenotomy, or as a substitute for it, Wecker has pro- posed advancement of the oculo-orbital fascia; while advancement of the tendon of the weak muscle is sometimes done. The cases in which undoubted benefit is to be expected are those in which the fault, whether of adduction or abduction, is of the same quality both for distance and near, and in which there is a strong impulse to binocular vision. With decided myopia, with anisome- tropia, with monocular amblyopia, the latter condition is imper- fectly fulfilled or is wanting. An operation may be advisable, but the result will be less certain. When, however, the cases are of the 1 Annales d'Oculistique, tome v., p. 139, and tome vii., p. 73. 2 Klinische Monatsblatter, 1869. ASTHENOPIA. 225 suitable kind, the surprising result is often seen, that the amount gained bjr the weak muscles is greatly in excess of the amount subtracted from the robust muscles; particularly is this true with insufficiency of the externi. This proves that we deal with func- tional conditions, viz., spasm and not exclusively with mechanical data. The effects of an operation may be satisfactory for some time and be followed by renewal of asthenopia and of the evidences of muscular error. It can also occur that the muscular discordances may after months be re-established, while no asthenopic symptoms have recurred. Cases which show a marked abridgment of muscular power at both ends of the visual line are unsuited to an operation. For them, prisms, regulated exercise, and general tonic measures are all that can be safely tried and some of these patients are in a pitiable condition. For them, advancement of weak muscles has been proposed, and Landolt records some successes. He also narrates, with commendable candor, grievous failures.1 There is always risk in advancement, of twisting the vertical meridian and introducing a new and most serious element of asthenopic disturbance. Yet by extremely careful operation and after-treatment this may be avoided. The results of a tenotomy may be satisfactory both mechanically and functionally for months, and by gradual relaxation of the cica- trix, diplopia may at length ensue and great annoyance. The field of diplopia may be lateral, not nearer than 25° from the median plane, and yet occasion great discomfort. If concave or prismatic or other glasses are worn, the error may be partially or sometimes wholly obviated. If, however, the field of double vision come close to the median plane, great disturbance follows. Sometimes a pa- tient learns to ignore the image of one eye, but the situation is re- grettable. It may be accepted as settled that tenotomy with free dissection of surrounding tissue is not fitting in muscular asthenopia; that with high degrees it is better to divide the operation between two eyes and at a considerable interval; the incision should be exactly at the implantation of the tendon and not in front of it. Graefe's rule of operating applied almost exclusively to cases of marked myopia, principally for insufficiency of the interni, and was to the effect that the eyes must be in equilibrium for a point about 20° on the side of the divided muscle, and on a plane 15° below the horizon. If for example, the left externus is divided, the patient, with a red 1 " Refractive Accommodation of the Eye," translation, Edinburgh, 188G, 226 DISEASES OF THE EYE. glass before one eye, should see a candle flame singly when held to the right 20° from the median plane of the face, and depressed about 15° below the horizon. A prism with base vertical is to be put in front of one eye, and the two flames must stand perpendicu- larly when the candle is put in the place of election above desig- nated. An error of 3° in excess is to be corrected by a suture which shall include the conjunctiva and more or less of the tendon. This proceeding is oftentimes too liberal and liable to leave diplopia, or such weakness of externi as to introduce another kind of asthenopia. He assumed that the muscle to be divided must always have a superfluity of energy, whereas experience shows that this may be far otherwise. It is safer to test the result of the operation on the median plane, and the weakened muscle must always be capable of exertion. In this position an excess of 2° or 3° is not serious, is often allowable, but the due preponderance of the interni must always be respected, and some abductive power, say 2° or 3°, should always remain. The test by a vertical prism is to some degree fallacious. It does not always teach the true place of equilibrium and if it show remaining error, while tests of adduction and abduction are satis- factory, the evidence of the latter is to be preferred until future developments indicate what should be done. My preference has been to perform complete tenotomy and con- trol its effect by a suture. Partial1 tenotomies have in my experi- ence been extremely uncertain and usually ineffective. With their frequent repetition at intervals of one or several weeks, as done by Stevens, I have had no experience. In operating, use a 4$ solution of cocaine. The wound is to be over the middle of the tendon and it is best to use forceps with projecting teeth which shall seize both tendon and conjunctiva. The scissors should be sharp-pointed and curved on the flat, the tendon is cut close at the sclera (a very useful scissors has been devised by Stevens, with blades made narrow for about one-third of an inch from the slightly blunted points; they are curved on the flat); carry under it a very small blunt hook, and cut off the insertion of the upper half of the tendon, one blade of the scissors being in front of, and one behind the inser- tion; put a second hook under the lower half of the tendon and sim- ilarly sever that. Keep close to the insertion and endeavor to avoid bleeding. Dr. Stevens' scissors with much reduced tips are well suited to making small wounds and may render the use of hooks unnecessary. Immediately test the effect by prisms and the candle, and modify the proceeding either for increase or diminution. En- deavor to make the wounds so small as not to need a suture, but if 1 See Standish, Trans. Am. Oph. Soc, 1889, p. 386, who practised partial tenotomy, with good effect, but the amount divided was not small. ASTHENOPIA. 227 too much effect has ensued, it must be employed. A light bandage may or may not be used, and usually 10 to 20 grains of phenacetine will be needed in two hours. There will be in normal cases a re- duction of effect during the next two weeks; sometimes this needs to be opposed by wearing prisms suitably placed. The immediate result of an operation will vary from 6° to 15°, and each case must be regulated according to its own peculiarities. It may happen that very little effect ensues, while on the contrary for apparently equal amounts of interference a large deviation may follow. This uncertainty depends both on the muscular power of the antagonist and on the density of the capsule of Tenon. Effects so small as 5° may easily be secured. Partial tenotomy may give effects varying from 0° to 3°. If it do good, as is alleged, the effect must largely depend on setting aside a state of muscular spasm, about whose existence I think, with Loring, there can be no doubt.—See Trans. Am. Oph. Soc, If the interni are to be relieved in cases of myopia by division of the externi, it is wise not to have more than 3° convergence on the median line. This will after a few weeks permit of a second opera- tion at which a closer correction can be secured. The ultimate result after six or twelve months is liable to be quite different, either by return of the original disproportion, or free tenotomy may eventuate in permanent homonymous diplopia. For this reason it is wise to proceed by careful steps as indications arise. Partial alleviation of symptoms is more frequent than complete cure. In operating on the interni for relief of the externi, one may aim at an immediate abduction of 8° or 12° according to the power of adduction. The higher the adduction, say if 50° and more, the greater will be the permissible amount of abduction procured, even to 15°. But with adduction not above 30° caution must be used and the resulting abduction kept below 10°. Sometimes only a slight effect is immediately gained, which increases within four days. In other cases the maximum is at once attained. Increased effect can be secured by wearing appropriate prisms. In all cases close attention must be given to the daily progress of events, and when needful, interference promptly employed. If an excessive effect appear, a correcting stitch can be inserted on the second or third day, b}T opening the wound with a fine strabismus hook. It is hard to resist the temptation to quote cases, but that would open too wide a gate. Without abating the general approval which is intended to be placed upon tenotomy for the relief of headache, eye-strain, and irrita- tions, both local and general, and placing myself squarely among its staunch advocates, some results of experience which have been contrary to just ex- pectations must be candidly mentioned. I have in three cases done teno- tomy of the interni for extreme headache in persons who had marked de- 228 DISEASES OF THE EYE. grees of insufficiency of the externi. They were highly neurotic. There ensued great relief of headache, but the capacity for eye work was deplor- ably abridged, although diplopia was not produced. Schweigger's small perimeter is the best instrument for ascertaining the lateral limits of binoc- ular fixation. On the other hand my present attitude on this subject is justified by the case of a gentleman having myopia and weak externi, seen first in 1863, who was then forty years of age. He had myopic astigmatism — ^s.q — ^c. V=liL. Always had headaches. Was treated by cups to temples, mustard footbaths, bichloride hyd., and gained no relief from head- ache by glasses or by treatment. In 1888 was found to have commencing sclerosis of lens in 0. S. and vision very defective. In 0. D.— 4.50s.C — 1.00c. 90°. V=0.6. In 1890 O.D. about same; O. S., V = fingers at two feet. Con- tinues to complain of headache, often waking with it in the morning; cannot wear distance glasses with comfort. Find that he has homonymous diplopia at 18', both with and without glasses, requiring prism 9°. Ordered prisms O. D. 5°, O. S. 4°. In five days convergence increased to 15° at 18', while with- out glasses at 10" has 9° divergence; with — 2D at 13" has equilibrium. After wearing prisms sixteen days reported almost complete relief of headache. One week later found at 18' convergence of 15° permanent with diplopia and did tenotomy of rectus internus O. S. The effect was at first controlled by stitches, but these were removed, and finally at 18' a convergence of 7" was left. This on the next day was reduced to 3°. In four days the convergence at 18' was 1°. For twelve days kept a patch over operated eye. For 18' has equilibrium, but very little muscular flexibility, to which the extremely dim vision of O. S. (cataract) contributes. For the near point has crossed di- plopia (divergence) of about 50°. By wearing full correction this is removed;; with his glasses at 18' abd. = 0°, add. = 8°. Has considerable difficulty in bi- nocular vision for the near. Eight months after the operation reported that there had been great diminution in the frequency of headaches; they would sometimes come and were severe. Cannot use eyes any more than he did previous to the tenotomy. Still has some diplopia, but images at 18' very close together. This case was a rare one of weak externi in myopic eyes. Not recognized when first seen in 1863, and not until twenty-seven years had passed, when patient had become sixty-nine years old. The nervous strain remained, the muscles were necessarily very weak, and the partial response to their relaxation by both prisms and tenotomy is a convincing argument in favor of the views presented. Perhaps a more careful tenotomy followed by another operation after a few months would have given better results. Another case of exceptional type, but having the guarantee of success by tenotomy after eighteen years' experience, is one of hyperopia with insuffi- ciency of interni. E. N. B., a boy, thirteen years, with O. D. -f- J, V = §£; O. S. -f-£, V=f#. Had severe pains and occasional diplopia. For six months wore 4" v C prism 4° base inward. In January, 1869, did tenotomy of both externi at one sitting. The measurements of muscular error are not complete. It appears that with his glasses and vertical diplopia there was 6° divergence at 20' and 14° divergence at 12". Six weeks later had with glasses at 20' add. 10°, abd. 3°. In 1873 was examined again, and vision had improved. O. D. -f-tV* V = ^; O. S. -f- ttjS- - Ac 180°, V = J£. With glasses at 20' add. = 16, abd. = O, with v.d. 4° convergence; with glasses at 12" v. d. 7° divergence. Is preparing for col- lege and reads three to four hours daily without pain. In 1887 was in- formed that he is practising law in Ohio and eyes never give any trouble. In 1865 a boy, fifteen years, with M i and insufficiency of interni, had com- plained of pain and asthenopia for four years. Material relief was gained ASTHENOPIA. 229 by — tV C prisms 4° bases inward. The amount of error is given only for 12", viz, 12° divergence with vertical prism. The rectus externus 0. D. was divided. The consequent homonymous diplopia continued for a short time and gave place to normal motility. Symptoms disappeared. After two years, viz., in 1868, trouble again came on, bringing about the discovery and correction of an important amount of astigmatism. He was ordered: 0. D. - |s. C TV<5- 180°c. V = f» -f, O- S. - TV». C tVc 180°c. V = fft +. For reading: O. D. - TVs. C - tVc 180°. O. S. -ts-CAc. 180°. Up to 1889 the correcting glass remained almost unchanged and visual acuity was normal. He went through college, became a lawyer, always read prodigiously and rapidly. The muscular conditions then (1889) deter- mined were: At 18' with glasses abd. = 5°, add. = 15°, with v. d.-^-. At 13" with glasses abd. = 15°, add. = 18°, with v. d. = 5° div. In March, 1892, the record was substantially the same. He has never made any complaint about his eyes and continues to use them unsparingly. In his case the cause of trouble was the muscular disturbance. Later the astig- matism came to the front. The preservation of healthful and vigorous eyes with notable and unequal degrees of myopia throughout a period of twenty- seven years under observation is an encouraging and noteworthy fact. It is right to say that during twenty years he employed one pair of glasses for all work ; that there has not been any choroidal crescent about the nerves ; that in 1873 he had the power of overcoming a prism of 10° with base vertical. My experience on this subject within ten years has been very large, and to cases within this period I make no reference. Examinations have been made more precise and interference has been ventured on in cases for which formerly nothing operative would have been done. The combination of prudence and boldness is absolutely essential in all these cases. Reference has been made to errors in a vertical plane as well as in simple adduction and abduction. Dr. Stevens1 finds these quite frequent and operates for them when not greater than 1° or 3°. I have sometimes corrected them by prisms and have in a few in- stances operated. I have found in most cases that correction of errors of adduction and abduction carried with it the adjustment of the error in the vertical meridian and that patients desired nothing more. A few words may be said about advancement as contributory to better equilibrium of muscles. My experience with this proceeding for asthenopia is recent and limited. I have had to do it for the undue effects left after tenotomy done both by myself and others, and have also done it to reinforce tenotomy of antagonists. If one secures small curved needles, the so-called "quarter round," and has them sharpened as if they were meant to penetrate the cornea, there will be little difficulty in accurately dosing the effect of the 1 Archives for Ophthal., xvi., 2, June, 1887, p. 149. '.30 DISEASES OF THE EYE. proceeding. A sufficient crescentic piece of conjunctiva must be excised right over the site of the insertion, the stitches must include the tendon and superjacent fascia, and the thread must have a needle at each end. To get a good anterior hold, the needle will go through the sclera easily and deeply enough, to answer all required traction, while the approximation of the wound will be done by forceps seizing the parts if there be much separation. One may use two or three sutures and I have found no puckering and very little reaction. In two instances I have taken a piece out of the tendon and stitched the distal part to a bit of the insertion left as a stump. Dr. Stevens practises an operation of this kind with very little dissection of tissues. Experience is as yet so limited, that one can only suggest rather than recommend. The topic we have thus considered is one which is at the present time actively discussed among ophthalmologists. Opinions vary, and the writer, while frankly avowing his own views, founded on a large experience, has only stated what thoughtful and careful ob- servation has taught him. Many things have been left unsaid, because in this field clinical experience is wonderfully diversified and more detail would hardly be suited to a text-book. Even the insertion of illustrative cases, to which there is strong temptation, would demand more space for adequate presentation of the varied phases of the conditions we meet than can be afforded. See Burnett, " Contributions to the Study of Heterophoria," Trans. Am. Oph. Soc, 1891, p. 217—a well-digested statement of cases. PART SECOND. CHAPTER I. GENERAL TREATMENT OF DISEASES OF THE EYE. We first speak of its proper protection from hurtful influences, viz.: from dust, smoke, glaring light, and extreme heat, by colored or transparent glasses, by shades, by seeking another locality, by a bandage, by seclusion in a dark room or in bed. Protective glasses are known usually as coquilles, are shaped like a watch-glass, and tinted either London smoke or blue, in various shades, known by letters A, B, C, D, etc. Very dark shades are objectionable in most cases, because they so diminish the light that the eyes are strained in gropinir about. The neutral tint is generally better than the blue. Blue glasses improve the distinctness of sight to some de- gree, in certain conditions. Workmen exposed to injury by chips of metal may wear large glasses of mica, if they will, but they are seldom inclined to accept them. Eye-shades may be single or double; they should be shaped according to their purpose; if to cut off light from above, as in reading, they should flare like a cap- front; to cut off light in all directions, they should lie flat and come around well on the temple. To lie flat, they should have a notch for the nose, be three inches wide, come to the temples, and will be kept flat by having the strings fastened three-fourths of an inch below the corners; these must go twice around the head. A mon- ocular shade to keep the lids closed, should be an oval whose length should be about two and one-half inches, and breadth one and three- fourths inches—the string fastened at the ends, and to go obliquely over the forehead and under the corresponding ear. If required, a packing of cotton may be put under it. A bandage should be made of thin flannel (i.e., merino, Avhich is a texture of both wool and cotton), be three and one-half yards long, and one and one-half inches wide, for an adult. In summer, muslin gauze may be substi- tuted. The width will be less in some cases, and always less for children. It goes about the head like a figure eight, and presses 232 DISEASES OF THE EYE. the eyeballs through a packing of absorbent cotton laid upon patches of muslin. To adjust a single or double bandage smoothly and firmly, requires a little practice. It is usually employed where some pressure is to be exerted on the eye. Some oph- thalmic surgeons prefer silk plaster which may be white or black and is laid on in strips or in one patch. When patients are kept in dark rooms, it is important not to have streaks of bright light at the edges of the shades or in the shutters. It hardly need be said that a patient wearing a bandage need not be im- prisoned in a dark room; the moral influence is bad, and the phy- sical effect on his attendants equally bad. I have known delirium produced by no other cause, in old people, after cataract extrac- tion. With dark rooms, unusual care must be given to ventilation and cleanliness. Many serious eye diseases require confinement to bed, and often it is difficult to make a patient submit to the hard- ship. The object is quietude of the whole body and absolute rest of the eyes, which a patient sitting in a chair or walking about under a bandage will not and cannot so perfectly maintain. I ad- vocate this only during the active period of acute disease—never in case the general health suffers or is unfavorably influencing the eye trouble. Even photophobia, which is usually the symptom necessitating seclusion in darkness, is sometimes aggravated by such confinement, especially in hysterical persons, in weakly or scrofulous children, and when the fear of light has outlasted the cause which originally excited it. To this point Dr. Agnew has .called especial attention. Such persons must be provided with smoked glasses, and sent outdoors to navigate for themselves. A proper understanding of hygiene and of the conditions of healthy nutrition in food, clothing, exercise, and air and occupation, is of the utmost importance in ophthalmic treatment. I shall have to emphasize this repeatedly. Protection from contagion may be secured by mechanical means such as bandages, and other devices, but special regard is to be paid to asepsis and antisepsis both in ocular pathology and in ocu- lar surgery. Besides the exposure to atmospheric germs which in tenement houses, asylums, hospitals, and barracks may become very grave, we always have bacteria and cocci of various kinds contained in the conjunctival secretion. They abound in the nasal cavity and with flagrant intensity in ozaena, and may be transmitted to the eye from the nasal discharges or by the lachrymal puncta. In the eyelashes, eyebrows, on the skin of the face, both with and without eruptive diseases, by the hands, by handkerchiefs, towels, rags, etc., we have ready means of contagion. It is needless to specify all that may be possible, one must inspect the wThole body and know a patient's habits and surroundings to find and remove GENERAL CONSIDERATIONS. 233 -all the sources of contagion. Complete and strict cleanliness of person, clothing, arid surroundings is the first requirement in asep- sis. Disinfection of rooms and wards, by vapor of burning sulphur (with attention to the free supply at the same time of watery vapor without which it is almost inert, but with which it is most efficacious (Squibb)), and the addition of carbolic acid or corrosive sublimate to the water used in scrubbing walls and floors, are important agents. In applications to the eye we are obliged to exclude some recognized agents or greatl}7 dilute them, because the organ is too sensitive to bear them in effective strength. We therefore rely more on asep- sis, of which cleanliness is the chief condition, than on antisepsis, when surgical operations are to be done, and reserve antiseptics for pathological conditions. We shall first speak of the latter. We •employ them especially in diseases of the conjunctiva and cornea, and while the utility of some of them has long been empirically known, our better knowledge of their mode of action helps us to use them more intelligently. Carbolic acid is little employed, be- cause it must be diluted to 1$ or 2$ solution. Boric acid, whose solubility is 4$, has wide application, because, while not really an- tiseptic, it is soothing and can therefore be employed freely to wash out morbid secretions. We separate the lids and lift them from the globe, perhaps by elevators or even a speculum, or by nipping the skin of the lid with the fingers, and wash out the conjunctival sac with a rubber bulb holding about two ounces; the whole cavity must be flooded. If there be much swelling of the lid or che- mosis, this may not be feasible to the full extent. Solution of cor- rosive sublimate 1:10,000 does not irritate, and 1:5,000 is easily borne. In severe morbid conditions even 1: 2,000 may be toler- ated, but the quantity will be small and a dropper employed instead of a bulb. A normal eye will sometimes show unpleasant reaction to solution 1:10,000. A third agent, and which completes the list of those most in use and commonly resorted to as antiseptics is chlorine water, or, as usually dispensed, the liquor sodas chlorinataa (Labarraque's solution), 1 part to 7 or 10. This is used with a drop- per. Next we mention the actual cautery employed often with sig- nal success in suppurations and ulcers of the cornea, less frequently in trachoma, either as the thermo-cautery of Paquelin or as the galvano-cautery. It will be referred to again. Hydrochinon and resorcin in Sfo solution have been employed with no special superiority over the fluids above mentioned. Salicylic acid is not much used except upon dressings. It is com- bined sometimes with borax, viz., a mixture of the two, each in 5$ solution. Benzoate of sodium, 5#, is counted antiseptic, and thymol, 1 : 1,200, yet they are rarely used in eye surgery. Iodoform in very fine powder—a point to be insisted on—is bv 234 DISEASES OF THE EYE. some much esteemed, yet by others is scarcely employed. Its efficacy is slow, and it must therefore be kept in contact with the tissues for a long time. It may also be mixed with vaseline and a bandage applied. Used chiefly in corneal ulceration and suppura- tion, it has been also lauded in purulent conjunctivitis, especially by English practitioners. Aristol is equally effective and is free from objectionable odor. Pyoktanin or methyl violet, 1 to 500 or 1 to 5,000, has value but not to a remarkable degree. Nitrate of sil- ver plays a great part in treating external diseases of the eye, and some of its potency is due to its antiseptic properties. Marpman says that in putrefying solutions of albumen, decomposition is arrested by solutions so weak as not to cause coagulation. These will be much less than one per cent. We might enumerate other substances habitually resorted to> whose efficacy in fact resides in their antiseptic qualities, such as yellow oxide of mercury, acetate of lead, etc., but there is no need. In operative work, of which extraction of cataract may be- taken as the type, and in which the cornea and conjunctiva are presumably normal, the employment of antiseptics has become thoroughly established. Nevertheless the same rigor is not prof- itable as in general surgery. Spray is never used; solutions which are in vogue are: boric acid, 3< or Vr. corrosive sublimate, 1:5,000 or 1:10,000; and biniodide of mercury, 1:20,000 to which a little alcohol is added (Panas' solution), and boiled water. As to the need for them we may bear in mind the investigations of Fick,1 that in 49 perfectly normal conjunctival sacs, he found only 12$ without bacilli, and 36 affected with slight catarrh contained them. He found bacilli, cocci, and tetrades or masses of sarcini. He enumerates seven different bacilli, three kinds of cocci, including the staphylococcus aureus, the pyogenic form, and sarcini (p. 54, I.e.). But more notable are the experiments of Gayet, of Lyons, who after carefully disinfecting the conjunctival sacs of his cataract patients, found by cultivations that microbes remained in 75<, and from 213 test-tube cultures, he concludes that antiseptic or aseptic fluids have very little influence over germs in the conjunctiva. It follows that copious washing is an essential factor, and because mercurial salts coagulate secretions, and Panas' solution, viz., hy- drargyri biniodidum 1 : 20,000 is entirely unirritating, these are to be preferred when slight catarrh exists. In other cases the fluid must simply be itself free from germs and, as already said, be freely used. Hence the utility of boiled water. We have also to bear in mind that wounds and manipula- tions must be made with the least possible bruising and violence, and here lies the crowning importance of neat and skilful operat- 1 " Ueber Micro-Organismen lm Conjunctivalsack/' Wiesbaden, 1887. GENERAL CONSIDERATIONS. 235 ing. If there be failure here, the soil is prepared in which germs delight to multiply. We must also avoid furnishing the fruitful soil in another way, viz., we must not operate if we can help it, when the constitutional conditions are unfavorable, i.e., in presence of rheumatism, syphilis, or any severe dyscrasiae; or if the disease be incurable, like diabetes, we must select the most favorable time. For similar reasons, conditions especially promotive of germ growth, like trachoma, pterygium, lachrymal diseases, chronic catarrh, must be cured, if possible, before operating. The most scrupulous care about disinfecting instruments, sponges, cotton, dressings, the hands, of all who have to do with the patient, and also the surface of the patient, his clothing, bedding, etc., must not be in the least remitted or abated. For the hands nothing equals soap and water applied with a stiff brush and with the addition of powdered borax to pene- trate under the nails. For instruments, soaking for thirty minutes in 5$ carbolic-acid solution; while boiling water, for scissors, spec- ula, forceps, and all instruments having joints and teeth is the best. Flat porcelain trays can be had in which to soak instru- ments, and some may be well brushed. The cutting edges of knives are liable to be dulled by carbolic acid, and they may be wiped with a clean rag after short immersion and then inspected with a mag- nifying glass. Immersion in alcohol helps to insure cleanliness by removing grease, but it is not antiseptic. Careful wiping by a moist and then by a dry rag is most essential. No specks of rust or stains should be tolerated, any more than a dull edge. In test- ing the edge and point, put several thicknesses of fine leather shav- ings or of gold beater's skin on the drum—a click or creak is the signal for rejection. If a point be merely turned, it may perhaps be straightened on the thumb nail. Test scissors on wet paper or on fibres of cotton; be specially careful about their points, and the edges should glide smoothly as the blades close. This introduces us to the operative treatment of the eye. It has always commanded great attention, and its scope has been largely extended. A better knowledge of pathology, the invention of new methods of operating, and higher skill in the manufacture and adaptation of instruments have conspired to make the opera- tive surgery of the eye one of the most brilliant chapters in medi- cine. Some general remarks are here in place. Shall anaesthetics be used ? Since 1884, when Dr. Carl Koiler called attention to the anaes- thetic effect of muriate of cocaine dropped upon the eyeball, gen- eral anaesthesia has been relegated to exceptional instances, in ophthalmic surgery. A summary of the effects of cocaine upon the eye is as follows; A 2$ solution, of which several drops are used,. 236 DISEASES OF THE EYE. causes at first a slight burning and smarting, then the lids open to an unusual extent, anaesthesia appears in from ten to twenty min- utes, the eye becomes pale by reduction of the size of the vessels, the pupil dilates moderately and the accommodation is slightly im- paired. A 4$ solution acts more speedily and affects the pupil and ciliary muscle more decidedly. The anaesthesia lasts about ten minutes. If the solution is dropped in again after three or four minutes, the effects are more speedy and last for fifteen to twenty minutes. Two or three instillations of 4< solution at intervals of ten minutes is commonly used for cataract operations. For stra- bismus the solution must also be dropped into the wound and will often sufficiently obviate pain. For enucleation the same has been done, but with less success, and deep injections have been practised into the orbital tissue of 2$ solution, but some risk of toxic effect is incurred. For iridectomy, if the iris be prolapsed, or a drop injected into the anterior chamber, pain upon excision of the iris may be abolished; otherwise not, unless a full dilatation of the pupil has been obtained, which implies its absorption and more or less decided anaesthetic effect. Besides the above effects, tension of the globe is reduced in most instances. Contrary effects, viz., increase of ten- sion, have been exceptionally noted when there was a tendency to glaucoma and the exaggeration has been caused by mydriasis. In almost all cases tension becomes subnormal. Its effects are exerted on both the sensory and sympathetic nerve fibres and hence its constricting influence on the vessels, and reduction of intraocular tension. It also constricts the lymphatics and hence dries the cornea, and frequently causes exfoliations and slight erosions of its epithelium. Indeed the remarkable effect was seen by Dr. Gruening of the whole epithelial covering of the cornea being lifted in a bleb, by exosmosis of the aqueous in a case of glaucoma for which he ventured to use cocaine preparatory to iridectomy. For advanced chronic glaucoma it is inexpedient to use it; for glaucoma simplex and for acute glaucoma it is admissi- ble. In operations on the lachrymal apparatus it has very limited effect and to reach the duct effectively it must be injected by a syringe. In operations on the lids, cystic tumors, etc., hypodermic injection within the area inclosed by a clamp forceps makes it per- fect master of the situation (2£ solution); without the clamp it speedily diffuses and is less satisfactory. For all operations on the cornea it is invaluable, especially in removing foreign bodies, in scraping ulcers, using the actual cautery, making punctures and incisions. Even when general anaesthesia is required because of the high excitability of the patient or of the severity of the operation, it is a useful adjuvant. It has no prejudical effect on the healing process and rarely causes toxic effects. GENERA L CONSIDER A TIONS. 237 Its application in inflammatory troubles is wide, viz., in chronic conjunctivitis, ulcers and phlyctenule of the cornea, in the pain of iritis, in combination with atropine, and in combination with eserine in especial cases of glaucoma where an operation is unadvisable. Its power of temporarily controlling hyperaemia as well as sensibil- ity, suggests many opportunities for its employment. Although temporary in its effect, it gives opportunity for examinations and applications of more positive value. Where great hyperaemia ex- ists it is less efficacious, and its hurtful effects on the corneal epithelium are less. In facial neuralgia a solution of 10# to 20£ dissolved in oleic acid or mixed with lanolin and rubbed along the painful nerve has a controlling effect. As spray in 5$ or 10$ solution it may be applied to trachoma, when about to be cauterized, or a fleck of absorbent cotton laid under the lid soaked in 10$ solution will so much control sensibility that some patients will even bear the actual cautery in the cases suited for its employment. Something must be said upon its toxic constitutional effects. As with all other drugs, persons exhibit most various degrees of susceptibility. The usual constitutional symptoms are imperfect and sighing breathing, pallor, indifference, unconsciousness or coma, seldom delirium, rapid and weak pulse, which often does not go above 90, but I have seen it go to 120, and may intermit and even go much higher. Less frequently there is giddiness, nausea and vomiting, slow speech, extreme sweating, a red rash, spasms of the limbs. The direct effects are on the heart and respiration. The antidotes are whiskey, ammonia, nitrite of amyl, digitalis, sin- apisms, friction and heat, hypodermic injection of morphine. In very sensitive persons and for prolonged operations we must use ether and chloroform. Therefore plastic operations, many lid oper- ations, enucleation, neurotomy, and sometimes tenotomy and often advancement of mucles will need general anaesthesia. As to operations which enter the globe: paracentesis seldom needs it; iridectomy may often be done without it, but it is more satis- factory to have the patient passive by general anaesthesia. Dr. Norris, of Philadelphia, has lately called attention to cases of fatal results of etherization in patients having Bright's disease. Experience has shown the value of this caution. The fatal result may not occur until after forty-eight hours, and it is to be heeded especi- ally in the fibrous kidney. For children under ten, I use chloroform, for older persons, ether by preference, but not seldom chloroform. When a long operation is expected, and the person is feeble, ether is to be chosen. For a quick operation I often administer chloroform. The primary stage of anaesthesia, before muscular relaxation has come and consciousness is not fully destroyed, and which lasts only 238 DISEASES OF THE EYE. part of a minute, requires a very small quantity of either ether or chloroform, and can often be seized as the happy instant for making an incision which will perhaps be all of the operation that the patient would not be well able to bear. Mr. Priestley Smith has suggested a full dose of bromide of potassium an hour before an operation, as a means of allaying excitement, and rendering a patient more sub- missive to the anaesthetic. I often give sodii bromid. 3 ss.-i., chloral hydrate gr. xv., the previous night, and repeat the dose an hour before the operation. The anaesthetic is more willingly accepted, and vomiting is less liable to ensue. In eye operations the ill-effects of vomiting are more serious than in general surgery, by promot- ing prolapse of iris, loss of vitreous, and intraocular hemorrhage. .For several years I have used an ether-inhaler which is valuable Fig. 87. because it takes up little space and offers the least obstruction in operating about the eye. It has a rubber face-piece, and has a dried bladder at the distal end of the box, which affords space for vapor. Eye operations should be done with the patient upon a table or a narrow bed. Operating chairs are by some preferred and may be taken into the patient's room: this applies to hospital practice. A liead-rest or clamp is useful, but an assistant can do this service. An operator who is ambidextrous will always sit behind the patient's head, on whichever eye iie may operate. But he will usually have to take his right hand for scissors, and sometimes, therefore, come to the front. One who is not equally apt with both hands, will change his place as the position of the eye or the place of operation requires. It is a great convenience to enjoy perfect use of both hands, but to many the accomplishment is never suffi- ciently realized, to warrant risking a patient's sight by a clumsy hand. As to brilliant display before spectators, no conscientious man would harbor the thought to the peril of his patient. How to gain needful skill ? There must be an original endowment of facil- ity of hand and a mechanical bent of mind. Practice upon fresh cadavers will teach something, but in them the eyes are too soft to GENERAL CONSIDERATIONS. 239 be suitable. Pigs' eyes mounted in an operating mask, or, in lack of this, fastened into the mouth of a bottle by a section of rubber tubing of proper size, or by strings, will teach one how to manipu- late in the anterior chamber, and the resistance in cutting the cornea. A light touch and steady hand, and sensitive appreciation of weight and resistance, are essential qualities. It is desirable to have the least number of assistants. In most cases but one is needed; sometimes a second, to give an anaesthetic and keep the head steady, is desirable. In manipulating the eye the operator should steady it by fixation forceps, and not let the assistant do it when avoidable. He thus keeps the command, and can co-ordinate his hands with accuracy. A fit speculum to keep the lids apart is an important instrument. It must open them ad maximum; it must not press on the globe; it must be out of the Fig. 88 way of the operator. I have experimented extensively with these contrivances, and find none perfectly adapted to all cases. The form which I prefer is shown in Figs. 87, 88. One which opens from the nasal side is sometimes convenient, especially if the globe is very deep, and gives a large field for work. But for deep eyes all such contrivances are imperfect, and one should have a smaller one for children and a larger one for adults. In case a speculum is impracticable, the operator may lift the upper lid himself by the point of his index finger. He draws up the lid by the skin as far as may be, then places the tip of his index beneath the edge of the lid, and pushes it back into the orbit. He does not drag or lift, but presses it under the orbital roof as he would push a sliding cover into the grooves of a box. If he does not choose to do this because the finger takes up room, he may use Desmarres' elevator, which is often necessary in examinations of the eye in children. It is made in sets of two and three sizes. An- other elevator which I use in operating when a speculum has been taken out, or when I wish to expose the upper part of the globe to the fullest extent, is made of fine steel wire and presses the lid farther under the orbital roof than anything else can, and it need not make pressure upon or even touch the globe. These instruments are figured in the catalogue of Geo. Tiemann & Co., New York. A simple strabismus hook will often be valuable as an elevator. Fixation-forceps are made with and without a spring catch. 240 DISEASES OF THE EYE. They should be used so as to turn the eye, not to drag it; the line of push must be at a tangent to the globe. If, for instance, the eye is to be turned down, the forceps will be attached just below the corneal margin, and be held perpendicularly to the globe while the latter is rotated down and the forceps take a direction approaching a tangent. Another way, often useful, and which is very conveni- ent for the operator, is to apply the forceps at the same place, to turn the eye by the same manoeuvre, and then bring the top of the forceps up to the root of the nose, and a light push keeps the eye down and exerts the least pressure. With anaesthetics, the forceps may even be left to fall obliquely over the supra-orbital notch and keep the eye down while the operator uses his hand for another purpose. He may give the forceps to an assistant, and its position will not need to be altered. The conjunctiva is liable to tear, and the patient must be persuaded rather than forced to turn the eye as desired, while the forceps simply maintain the position aimed at. Regarding other instruments, they will be considered when their special uses are to be described. Medicines which have a special applicability to the eye, are those which act on the pupil and the ciliary muscle, viz., mydriatics and myotics. Of the former we have atropiae sulphas, duboisia, homa- tropiae hydrobromas, daturiae sulphas, hydriodate of hyoscine. All of them are poisonous, and can exert toxic effects when used in sufficient strength as collyria, because they go through the cornea by endosmosis and enter the circulation by solution in the aqueous. humor. They also pass down the tear-passages to the throat, and are there absorbed. Sulphate of atropia is the most common of these remedies. It affects the dilator iridis before it affects the cil- iary muscle. It likewise is an anodyne to the sensitive nerves of the cornea and iris. It is used in solutions from one-fourth grain to sixteen grains to the ounce. It was erroneously thought by Graefe to relieve intra-ocular tension ; when it fully paralyzes the cil- iary muscle and iris, the eye often feels much relief. On the con- trary, all mydriatics, even cocaine muriate at times, intensify intra- ocular pressure simply because the iris is pushed toward the angle of the anterior chamber (Holtze and Graser), while myotics dimin- ish the pressure because the iris is pulled away from the angle. Atropia sometimes irritates the conjunctiva and after long contin- uance excites papillary conjunctivitis. Occasionally even the skin of the lids becomes erythematous. To render unpleasant consti- tutional effects less probable, atropia may be mixed with vaseline, or dissolved in castor oil (Green). If toxic effects appear, they will come as dryness of the fauces, which need not be heeded; but more important are, quickening and weakness of the pulse, flushing of the face, palpitation of the heart, headache, nausea, prostration* GENERAL CONSIDERATIONS. 241 garrulous delirium, desire to urinate, and sometimes muscular vio- lence. The antidote will be brandy and morphia, and in urgent cases hypodermic injections of muriate of pilocarpine, gr. \, every fifteen minutes. Duboisia has more effect on the eye than atro- pia and it does not irritate the conjunctiva. Its toxic effects come more quickly and are more alarming, the prostration being ex- treme. Homatropia, a derivative of atropia, acts more feebly than either of the preceding. It dilates the pupil, if used in the strength of gr. iv. ad oz. i., in about half an hour, and has moderate effect on the accommodation; but in twenty-four hours its influence is gone. It is serviceable for purely ophthalmoscopic work, but must be taken at gr. xx. ad % i. for refractive determinations. The full effect of atropia, whenever obtained, will last for from seven to twelve days. Of daturine nothing need be said. Equal parts of hydro- bromate of homatropine and sugar of milk have been used by Mit- tendorf, dusted in the eye with a brush. Hydriodate of hyoscine is our most powerful mydriatic. Hirschberg reports that \i> solution is liable to cause toxic symptoms. Emmert used it with safety in ■jV # solution, i.e., gr. ^ ad § i. The important myotics are the preparations of Calabar bean, the sulphate and salicylate of eserine, and the alkaloid of jabo- randi, hydrochlorate of pilocarpine. The eserine preparations should be used in solution, gr. ss. or gr. i. ad § i.; if stronger, they become very painful by exciting spasm of the ciliary muscle. They stimu- late the sphincter iridis and the ciliary muscle, and irritate the con- junctiva. Their effects are more fugitive than those of atropia in equal strength. In strong solution they excite pain in the eye and around the orbit, and can even cause clonic spasms of the extrinsic muscles. They reduce ocular tension and it is claimed by some that they reduce the calibre of the vessels. They are used in in- flammations of the cornea with much confidence. The solution of the sulphate undergoes change to a reddish color, which some- what abates its efficacy. A second myotic, but far inferior to eserine, is the alkaloid of jaborandi, viz., pilocarpine, of which the hydrochlorate and the sali- cylate are the preparations in use. Its value in treating diseases of the eye rests more upon its constitutional than on its local effects. As a topical application its minimum strength is 1 to 400, and if stronger, its influence does not appear to increase (Jaarsma, Thesis 1880, quoted by Landolt). It is usually prescribed in strength gr. £ or gr. ij. It contracts the pupil moderately and approximates the near-point and the far-point slightly. Its effect on the pupil appears in about thirty minutes and lasts for twenty- four hours. On the accommodation the effect begins in two and a half hours and lasts two or three hours. It has therefore only 16 242 DISEASES OF THE EYE. limited value in ordinary needs, but because it is not irritating and topically devoid of unpleasant effects, it serves a good purpose in mydriasis caused by paralysis of the third nerve, and in feeble ac- commodation. Its constitutional uses are extensive and will be duly considered. Its poisonous effects should be mentioned. Its normal results are salivation and sweating, but added to these are temporary increase of urine, thirst, vomiting, nausea, belching, colic, and diarrhoea. The pulse is at first increased, then becomes normal or too slow. The action on the heart is through the pneu- mogastric nerve; prostration is caused by nausea and vomiting more than by a specific influence. But it is recognized to be a most capri- cious remedy and must be given internally in small doses, viz., 0.01 or 0.02, i.e., ^ Sr- to i gr. Its antidote is atropine and homatropine, besides general stimulation, galvanization, etc. The hypodermic injection of the muriate of pilocarpine (gr. ^ to gr. |) has seemed to do good under certain peculiar conditions; for instance, in the late stages of chronic keratitis or scleritis, especially in gouty subjects, and also in the late period of gouty or rheumatic iritis, and in serous uveitis. Virtue is claimed for it in subretinal effusion. On the whole, the remedy has seemed to me to be overrated, although its powerful action on the salivary glands and on the skin gives it influence over local disease which doubtless can be sometimes suc- cessfully applied. As yet the indications for its use are not pre- cisely formulated. A case is recorded where by mistake a 20$ solution was hypodermically injected (Sziklaix). The case was one of absolute glaucoma in which sclerotomy had been done and 2$ injections of pilocarpine employed. When the tenfold dose was given, the symptoms were abundant salivation and sweating for five hours. There was copious evacuation from the bladder and from the bowels, vomiting and belching, from time to time squeez- ing and tearing pain in the eyes. Afterward great prostration. Treatment is not related. Vision said to have been impaired and so remained for two years, but to what degree is not stated. The Turkish bath is a similar measure, and is to be employed in similar conditions. . It has decided value, but it is also capable of mischief if not properly regulated. Another myotic is muscarine, the alkaloid of Amanita muscaria, which is little employed, but may be mentioned because, unlike eser- ine, it causes slight contraction of the pupil, but strong spasm of accommodation. It is very powerful and acts more on the punctum remotum than on the punctum proximum. It may be used in solution 1 to 400 or 1 to 100. Its antidote is atropine, but not vice versa. There are other mydriatics which might be mentioned, as gelse- 1 Jahresbericht fib? Ophth., 1881, p. 2G3. GENERAL CONSIDERATIONS. 243 mine, daturine, which is identical with atropine, nitro-atropine, and nitro-daturine, but they are seldom useful. Cocaine has slight mydriatic effect, and a paper was written on this property of it by Von Aurep in Archiv fur gesammte Physiologie, XXI., p. 38, in 1879. Unfortunately its peculiar anaesthetic properties were not then discovered. As a summary of the whole: Among mydriatics we choose atropine sulphate or salicylate, in cases where a prolonged effect on the pupil and the accommodation is required. It is the mydriatic by far most frequently used for therapeutic purposes. In case it cause disagreeable effects, either local or general, we substitute duboisine sulphate or salicylate. For a less prolonged but vigorous effect on the pupil and accommodation we use duboisine gr. ss. ad oz. i., but must be watchful against toxic influences. Where a brief effect on the pupil and accommodation is desired, we use hydrobromate of homatropine 1$, or muriate of cocaine 4$. The one most likely to cause unpleasant constitutional effects is duboisine; that most likely to produce conjunctival irritation is atropine. All are liable with glaucomatous eyes to produce an acute attack, and in the ratio of their energy. Of the other therapeutic uses of these rem- edies it is not intended here to speak. Of myotics the best is eserine salicylate or sulphate 0.1$ or gr. ss. ad oz. i. It contracts the pupil, causes spasm of accommoda- tion, and reduces intraocular tension. It also has other valuable therapeutic effects in inflammations of the cornea, to be referred to under that head. For a less energetic effect hydrochlorate of pilo- carpine may be employed. While watery solutions are most com- monly employed, mixtures with vaseline are very convenient, and Dr. Mittendorf has introduced 1$ triturations which do not spoil by keeping, are easily applied, and are very convenient. He uses of either the mydriatic or the myotic 1; pulveris gum acac, 50; pulv. sacchar. lactis, 50; M., to be dusted into the eye with a camel's- hair pencil. We are called upon to apply leeches, as, for example, for severe inflammations, and for inflammations of the deep textures. In reality they are not frequently employed. They should be placed on the temple, and not too near the lids—never on the lids or in their near vicinity. The artificial leech of Heurteloup is a cup- ping instrument which draws blood rapidly, and is useful for deep- seated congestions. It has quite superseded the ordinary cupping apparatus. As a matter of fact, the abstraction of blood is re- sorted to, in visible ocular inflammations to a much less degree than formerly, and only in those which are attended by great pain and hyperaemia. For deep seated diseases it is used in a way ad- vised by Graefe. From one to two ounces of blood are withdrawn 244 DISEASES OF THE EYE. rapidly from the temple, and the patient remains in a dark room for twenty-four hours afterward. This proceeding is repeated once in three, seven, or fourteen days, according to the character of the case. Blisters and external stimulants, such as tincture of iodine, are not as much used as they formerly were. Their value as antiphlo- gistics is almost nil, and they were formerly in favor because the cases were too often incorrectly diagnosticated. As remedies for neuralgia they sometimes are useful, and in a few other special conditions. Of external applications none is so common as water of various temperatures, and its effect is modified in the most remarkable manner by the mode of its use. For violent inflammatory attacks, as after wounds or in severe purulent conjunctivitis, a block of ice is kept beside the patient, and bits of muslin transferred from the ice to the eye every minute so long as the symptoms demand such extreme cold. We may use the water of higher tempera- ture until it has no effect upon the surface, but serves merely to soften the secretions. From this point we may go until we get to 106° F. or 114° F. To keep the water cold the compresses must be constantly renewed; so, too, in attempting to keep it warm. To avoid such frequent change various contrivances have been adopted. I sometimes let a patient hold a small piece of ice, wrapped in muslin, upon the eye as long as it feels agreeable, and I have used a small rubber bag as large as a hen's egg, filled with ice, and stopped by a cork; but neither of these is very satisfactory. Contrivances for keeping up continuous irrigation, by coils of rub- ber or tin tubing, have been made (Becker, Chamberlain). For most cases we need moist cold or moist heat, and this we get best by compresses wrung out of water. Eye-douches are useful for certain chronic cases and are easily contrived, and may be for warm or cold water. They are used for only a few minutes at a time. For con- tinuous moist heat, a good appliance is a poultice of ground slippery elm (ulmus flava) bark. Spongio-piline dipped in hot water, covered by oiled silk, is cleanly and serviceable. A bunch of absorbent cot- ton is exceedingly serviceable. It is an old rule which holds good to-day that applications to the eye should be of such temperature as shall be grateful to the patient. This cannot be accepted abso- lutely. For example while to the early stage of many external in- flammations hot water is a relief, if kept up for several hours or if, as too often is done, a hot poultice be bound on the eye, an cedema- tous effusion is promoted which ensues in possible ulceration of the cornea and in such relaxation of tissues as to protract the attack. Some cases reject all moist applications; these are apt to be such as have little or no secretion except tears by reflex irritation, viz.,. GENERAL CONSIDERATIONS. 245 scleritis and iritis. Dry heat by a folded and warm napkin is often most satisfactory. On the other hand, when secretion is abundant, moist applications wash it away and by their temperature control the exudation to some degree, as they influence the contractility of the vessels. It is for the great majority of cases proper to use local applications for only a portion of the time—sa\~ for ten minutes or for thirty minutes three, four, six, ten times a day. Intermittent use is the rule in moderate cases. Continuous use applies only to severe cases. Details in this matter will come up in special dis- eases. We next come to the so-called collyria, whose name is legion, and whose utility is regarded by the public as of the highest moment. They are to be given almost exclusively in cases of con- junctival disease. They are soothing, stimulating, astringent, and, caustic. The indication for them will be found in the presence of secretion which comes ordinarily from the conjunctiva, although the primary lesion may be in another tissue. This secretion is serum, epithelium, fibrin, pus- and blood-cells. The remedies are chosen according to their power of causing contraction of the vessels and coagulation of the secretion, or as they soothe the irritated nerve- fibres. We do not know enough of the modus operandi of medi- cines to reason exactly on this subject, and we act according to the results of experience. It is simply my purpose in this place to speak a warning against the misapplication of such remedies. To apply to iritis, cyclitis, and pure scleritis, such remedies as tannin or alum, or nitrate of silver, or sulphate of zinc, is utterly mischiev- ous. So, too, they do harm in many, if not in almost all cases of :acute keratitis. Before any " drops" are ordered, a diagnosis of the disease must be made, and if this be not made, no drops capa- ble of mischief are to be thought of; better temporize by lukewarm water, or a weak solution of borax, or, best of all, frankly state the difficulties of diagnosis, and seek further light. Such conduct will save many an eye which rashness or false pride would ruin. An indication of the highest importance in diseases of the eye 's the regulation of its tension, especially to reduce it when excessive. The cases in which it is below par are usually of a chronic charac- ter, and are less amenable to improvement. To reduce increased tension we have, first, eserine as a medicinal agent. But the chief means are mechanical, viz., puncture of the cornea, and often not more than two drops of aqueous fluid will be removed. Again, free division of the cornea to let off all the aqueous fluid, and with it morbid products like pus or lymph in the anterior chamber. Thirdly, we have sclerotomy, which is done at the margin of the anterior chamber by a peculiar method, and also at the equator. Fourthly, we have iridectomy, which is done at the sclero-corneal 246 DISEASES OF THE EYE. junction, and includes excision of a piece of iris. Fifthly, under special conditions after chronic iritis and loss of the lens, division of a mass of agglutinated tissue (iridotomy) relieves extreme ten- sion. Sixthly, I have seen two cases where removal of the whole iris through a small wound reduced the size and tension of a staphylomatous globe. In ordinary practice, paracentesis of the cornea and section of the cornea are proceedings which may be adopted by physicians who do not regard themselves as skilled operators, provided they cannot refer their patients to more ex- perienced hands. The other proceedings need surgical training be- fore they should be attempted. Paracentesis cornece is liable to be followed in certain cases by increased intra-ocular congestion and therefore the indications for it must be definitely recognized. CHAPTER II. THE EYELIDS AND CONJUNCTIVA. Anatomy. The eyelids are formed at about the second month of embryonic life as folds of skin which grow toward each other, and coming into contact at about the end of the third month, adhere at their mar- gins by continuity of their epithelium. They remain closed until a short time before birth. The upper lid is much the broader, and in the substance of each a smooth firm portion can be distinguished which is known as the tarsus, and is composed of condensed fibrous tissue. It was because of its stiffness formerly regarded errone- ously as cartilaginous. The tarsi may be spoken of as the frame-work of the lids; where they meet they are thick, while their orbital edges are thin. That of the upper lid is about ten millimetres wide at its middle, and that of the lower lid is about five millimetres wide. Their general form is exhibited in the diagram (see Fig. 89). The space between them is called the palpebral fissure. Its temporal end is acute, while the nasal extremity is round- ed. The tarsi are united to each other at their extremities and also bound to the subjacent bone by internal and external palpebral ligaments. When open to its full extent the palpebral fissure is more rounded at its inner than at its outer extremity and is likened to the shape of an almond. At the inner angle (canthus) we find a fleshy mass called the caruncle (caruncula lachrymalis); just exterior to it are the openings of the tear passages (puncta lachrymalia) situated upon little eminences; that of the upper lid is usually the more elevated. The length of the palpebral fissure varies materially in different persons; it may be taken as 30 mm. in men. Its width at the mid- dle when looking straight forward is about 12 mm., and the border of the upper lid covers the upper edge of the cornea for 1 or 2 mm. The outer canthus stands at a level 3 to 6 mm. higher than the inner canthus when the lids are open, and when closed the Fig. 89.—The Tarsi seen from be- hind. They have been isolated from other tissues and remain joined at the external and internal angles by the lateral ligaments, external and internal (or medial). 1, Posterior surface of tarsus superior — on its edge the openings of the Meibomian follicles; 2, tarsus inferior; 3 and 4, punctum lachrymale superior and inferior; 5, external or lateral angle; 6, internal or medial angle of the eyelids. 248 DISEASES OF THE EYE. fissure is neither horizontal nor straight. When the eye looks up- ward the palpebral opening increases to about 15 mm. in width, and when it looks down the opening decreases to 7 or 9 mm. The borders of the lids are fringed with short, stiff hairs (cilia or eye- lashes) which are thicker and longer in the upper than in the lower lid. They are slightly curved and the respective rows oppose their convexities to each other. (See Fig. 90.) When the lids are open we have in the upper lid a deep fold caused by the retirement of the upper edge of its tarsus into the orbit, and called the sulcus orbito-palpebralis superior. Above it the skin is more prominent and is known as the orbital portion of the lid. Similar peculiarities exist in the lower lid, but are less conspicuous. We have the sul- cus orbito-palpebralis inferior, and in addition another less em- phatic line, the sulcus palpebro- malaris (Arlt). In certain per- sons and particularly in the obese and after middle life, the above- named sulci may be strongly marked. These features present in different persons the widest variations. Above the upper lids we have the eyebrows (su- percilia) situated at the upper edges of the orbits (see. Fig. 90). The inner surface of the lids applies itself closely to the eye- ball, and is lined by a membrane which is called the conjunctiva be- cause it joins them to each other. Its description will be given here- after. The lids are furnished with muscles to open and close them, and with several varieties of glands. The closure of the lids is effected by the orbicularis muscle, which lies just beneath the skin, to which it adheres loosely by connective tissue and without the intervention of any subcutaneous fat. Its fibres are more or less circular, con- stituting a sphincter, and extend over a part of the superciliary, the temporal, and the malar regions. They are inserted into a tendon which adheres to the lachrymal bone and are also inserted directly into the adjacent bony wall. The tendon crosses the lachrymal sac at about its middle and contributes to the internal palpebral ligament. Those fibres of the orbicularis which lie upon the tarsi are paler than the remainder, and certain bundles which lie close to the lid border and near the conjunctival surface are known as the ciliary muscle of Riolani; see figure, p. 251. The or- bicularis is supplied by the seventh or facial nerve. Fio. go.—Right Eye and surroundings. 1, super- cillum or eyebrow; 2, sulcus orbito-palpebralis; 3, papilla lachrymalis superior; 4, papilla lach- rymalis inferior; 5, canthus externus (lateralis); 6, canthus internus (medialis); 7, caruncula lach- rymalis; 8, plica semilunaris; 9, sulcus orbito-pal- pebralis inferior: 10,11, sulcus palpebro-malaris. THE EYELIDS AND CONJUNCTIVA. 249 The levator palpebrae superioris originates at the apex of the orbit, lies close to its upper wall, grows wider as it comes forward, and has a threefold insertion into and about the upper edge of the tarsus (see Fig. 91.) The most anterior part of its tendon runs as a layer of fibrous tissue down upon its anterior surface and merges with the aponeurotic layer which comes down from the upper border Fig. 91.—Vertical Section through the Globe and Orbit in the direction of the orbital axis, with closed Lids. 1, skin of upper eyelid; 2,2, musculus orbicularis palpebrarum; 3, fascia palpebralis superior; 4, border of frontal bone; 5. tarsus superior, schematically represented; 6, musculus le- vator palpebne superioris; 6a. its principal tendon which spreads out between the tarsus and mus- culus orbicularis; 66, the smooth musculus palpebralis superior; 6c, conjoined insertion of the mus- culus levator palpebrae and musculus rectus superior going to the conjunctivae; 7, musculus rectus superior; 8. 8, Tenon's capsule; 9, tendon of musculus rectus superior, passing through Tenon s space 10, limit between inner orbital fat, 11, and supravaginal space 12; 13, musculus rectus oculi inferior; 13a, extremity of its fascia, going to lower lid; 14, cross section of musculus obliquus infe- rior: 15, skin of lower lid; 16, tarsus inferior, schematically represented; 17, fascia palpebralis infe- rior; 18, 18, periorbita; 19, 20, fornix conjunctivae; a, optic nerve; b, vitreous; c, lens; d, cornea. of the orbit and pushes into the fibres of the orbicularis muscle, thus binding together all these structures. The middle layer is inserted into the upper edge of the tarsus and consists largely of smooth muscular fibres. A third portion of the tendon dips back to mingle with fibrous prolongations of the insertion of the rectus superior 250 DISEASES OF THE EYE. and goes to the superior fornix of the conjunctiva and sends lateral off-shoots to be attached to the outer and inner walls of the orbit. By this arrangement the movements of the upper lid and of the globe when looking upward are co-ordinated, and a layer of dense membrane shuts in the contents of the orbit above the eyeball. The levator palpebral superioris is supplied by a twig from the third nerve. It may here be remarked that the rectus inferior, after its insertion into the globe, sends a tendinous prolongation, in a man- ner similar to the arrangement of the levator of the upper lid, to the edge of the inferior tarsus and to the inferior conjunctival for- nix l (Schwalbe) and to the fascia palpebralis inferior. (See Fig. 91.) Still another muscle is to be mentioned which lies behind the lachr3rmal sac arising from the crista lachrymalis and bifurcating into two tendons, of which one is inserted into the border of the upper and lower lids respectively. It is called musculus lachry- malis posterior or muscle of Horner. The glandular structures of the lids are numerous. In the skin are sweat glands and xery fine scattered hairs. The follicles of the cilia are furnished with sebaceous glands, the glands of Moll, and in each tarsus is an important series of glands, arranged like cur- rants on a stem, known as the Meibomian, which run vertically in their substance near their posterior surface and open by minute orifices upon the free border of the lids behind the rows of cilia. A section parallel to and about one millimetre above the free border of the lids will cross the hair follicles, the glands of Moll and of Meibomius, and reveal a number so great as will be likely to sur- prise one who has not before looked at such a section. The eye- lashes of the upper lid are from 8 to 12 mm. long and said to have a life varying from 100 to 150 days (Donders). The relations of parts in the upper lid will be best understood by the figure (see Fig. 92). Still other glands are to be found in close relation to the con- junctiva, viz., the acino-tubular glands of Krause, which lie at the border of the tarsi near the fornix, more numerous in the upper than in the lower lid, and other similar glands, very few in number, imbedded in the tarsal conjunctiva and in the tarsus. These are regarded as accessory lachrymal glands. In the tarsal conjunctiva are certain follicular cavities formed by irregular involutions of its epithelium which are called the glands of Henle and will be re- ferred to again when describing the conjunctiva. The large number of glandular structures thus mentioned give rise, as would be expected, to many and various pathological condi- tions to which attention will be called, and some of them are obsti- nate and distressing. The function of the lids is to protect the eye both from mechan- 1 " Lehrbueh der Anatomie des Sinnesorganes," p. 242, 1885. THE EYELIDS AND CONJUNCTIVA. 251 ical injury and from excessive light, and to distribute over it the moisture furnished by the numerous glands. The movement of the lids is both voluntary and involuntary or reflex. The latter is de- termined by the fibres of the fifth nerve which supply the cornea and ocular conjunctiva acting upon the orbicularis and es- pecially upon those of its fibres which traverse the tarsal por- tion. The persistent opening of the lids during waking hours is provided for by the exist- ence in the levator palpebral superioris of certain unstriped fibres (H. Miiller) to which ref- erence has been made. The eyelids follow, as has been said, the movements of the cornea up and down, and in so doing the palpebral opening varies in width, becoming larger in look- ing up, and narrower in look- ing down. The opening of the lids is performed almost wholly by the lifting of the upper lid, but in looking down the lower lid is also made to descend by the indirect attachment to its tarsus of the tendon of the rec- tus inferior. (See Fig. 91, page 249.) Under special impulses the separation of the lids can be notably increased and so much, as to show a border of sclera both above and below the cornea. This occurs under emotions of surprise, of fright, of earnest attention, and ap- pears in exophthalmic goitre (Basedow's disease). Droop- ing or falling of the lids comes from fatigue, from paralysis of the levator, and from mechanical hindrance such as thickening of the conjunctiva, etc. Fig. 92. —Sagittal Section through the Upper Eye- lid. 1, skin; 2, palpebral portion of the musculus or- bicularis oculi; 2a, its inner portion, designated as the musculus ciliaris Riolani; 3, cilia; 4, gland of Moll, opening into a hair follicle; 5, Meibomian gland; 5a, its orifice; 6, indication of the ill-defined limit of the tarsus; 7, loose connective tissue be- tween tarsus and anterior insertion of the tendon of the musculus levator palpebrae superioris; 8, anterior connective-tissue-like insertion of the tendon of the musculus levator palpebrae superioris; 9, its middle layer non-muscular, called the musculus palpebralis superior. (H. Miiller.) 252 DISEASES OF THE EYE. Blepharitis Marginalis. Ophthalmia Tarsi. Blepharo- Adenitis. We have various degrees and kinds of this affection; for in- stance : 1st, chronic hyperasmia of the border with slight thicken- ing; 2d, some redness wTith an accumulation of yellowish, fatty material at the base of the lashes, the hypersecretion of the glan- dules, a kind of seborrhoea; 3d, ulceration, minute abscesses, crusts gluing the lashes together and sometimes severe inflammation of the whole border; 4th, after long continuance the lid border becomes smooth, red, glazed, everted, thickened, weeping, and destitute of lashes (lippitudo). It is characteristic that the hair follicles atro- phy, the lashes dwindle, become pale or curl up and fall out. Some- times decided ectropium, and eversion or occlusion of the lachrymal puncta, takes place, this more frequently in the aged or the un- cleanly. The disease occurs most often in the young with delicate skin and light hair, and in the strumous. It is sometimes a kind of eczema." In very many cases it is associated with some refractive or muscular error and is only an expression of functional strain, for which no local remedies will avail, until proper glasses or other correction are employed (Roosa) (Schirmer). Chronic conjunctivitis, trachoma, phlyctenula, are frequent con- comitants. The ailment is apt to be chronic, but except in the in- veterate form mentioned as the fourth type, will usually yield to proper measures. Treatment.— The first two forms require soothing lotions, warm water or warm milk and water, and for the seborrhoea it should be made a little alkaline with bicarbonate of potash; at night a mix- ture of boracic acid powder and vaseline, gr. xxx. ad oz. i., may be applied, or soft oxide of zinc ointment. For the ulcerative form the crusts are to be softened, and as much as possible removed, and the following ointments may be used: two grains of hydrarg. oxid. flavse to one drachm of vaseline or amylo-glycerin; or, ung. citrini, gr. x. vel. xx., vaselini, 3 i., to be applied night and morning, or, in bad cases, more frequently. In a large number of cases, the best method is to pick off the crusts with fine forceps or the finger- nails, and cauterize the exposed ulcers with a fine point of nitrate of silver. It often bleeds, and the caustic hurts. In cases of ex- tensive incrustation, and especially in young children, the lashes may be cut off with scissors to facilitate the denudation and cau- terization of the ulcers. The subsequent use of stimulating salve will then control the disease. But if the person be the subject of error of refraction, or of other error which causes eye strain, the "removal of the blephharitis will not only demand the usual local THE EYELIDS AND CONJUNCTIVA. 253 treatment, but also that the error be corrected. (See Part I. of this treatise.) In specially obstinate cases the evulsion of the lashes may be demanded (epilation) with use of lotions of acetate of lead (Liquor plumbi subacetatis, 3 i.; Aquae, § viij. M.) and the ointments above mentioned, especially the yellow oxide of mercury. Treat- ment of conjunctival disease by nitrate of silver, gr. ij.-v. ad oz. i., must not be neglected. For the chronic thickening with eversion and loss of eyelashes (madarosis, tylosis), squamous blepharitis,. stimulating ointments of more intensity may be used, such as an ointment of Hebra's: IJ Emplast. diachylon co.,1 Olei olivae,.....q. s. M. Or, 5 Olei cadini,.....1 Vaselini,......2. M. Apply every night. The crystal of sulphate of copper may be applied daily, or the nitrate of silver, pure stick, pro re nata. Sometimes constitutional treatment of scrofulous conditions is not to be omitted. Hordeolum or Stye. This affection is a phlegmonous inflammation at the tarsal edge, which forms a small and generally painful lump. It is apt to be associated with chronic blepharitis or conjunctivitis, and often de- pends on general debility. In its inception it may sometimes be checked by applying a bit of ice wrapped in muslin for a few min- utes repeatedly, or by pulling the cilium which passes through it. One is apt to follow another in succession. When suppuration is unavoidable, a poultice of ground slippery elm bark (ulmus flava) is most comforting, and a puncture should be made at an early period. General tonics and mild astringents are the proper reme- dies to prevent their recurrence; but it is important also to inves- tigate the state of refraction, because what causes eye strain will provoke styes. Another frequent concomitant and favoring condi- tion, is nasal catarrh, which will also need attention. 1 Emplastrum diachylon co. is made as follows: Emplast. litharge, 12 parts; flour, 1 J- parts; ammoniac, galbanum, turpentine, each 1 part. :254 DISEASES OF THE EYE. Chalazion, or Cystic Tumors. Obstruction and distention of some of the follicles of the tarsus, more frequently of the Meibomian, is the origin of these tumors. They are painless, imbedded in the tarsus, and the skin is freely movable over them. They vary in size, and are apt to come in crops. The sac wall is usually thin, and as the tumor enlarges it causes a reddish or yellowish projection on the conjunctival sur- face, and sometimes presents granulations. The contents are a glairy, mucilaginous substance. Microscopic examinations have shown that nutritive disturbance in a Meibomian folli- cle, excites chronic inflammation in the surrounding connective tissue which leads to an infiltration with small cells. By confluence of several foci of infiltra- tion, a nodule is formed composed of granulation tissue and giant cells. This results in mucoid softening and its escape by ulceration (Fuchs). Cocci are also found within them. Fluctuation is never felt, and I have sometimes found a solid, fibrous tumor when I expected to meet a cyst, and at times the cyst wall has been extremely thickened. When small, the tumors are not troublesome, and they occasionally disappear. If they reach a size to be annoying, they must be excised. We may do this on the skin surface, through a wound par- allel to the lid-border, and no perceptible scar is left. The cyst may be opened on the inside surface if it pro- ject notably in this direction, and the contents scooped out with a sharp spoon. Sometimes the tumor runs for some distance up the lid along the line of a Meibo- mian duct: it will be apt to point at the lid border. Here a deep puncture may be made with a narrow knife and a sharp curette pushed up into the tubular cyst to scrape its walls and evacuate its contents. Special forceps have been con- trived by Desmarres, Snellen, Prout, and Knapp, to inclose the tumor in a clamp to prevent bleeding. Before applying it, drop into the conjunctival sac a 4$ solution of cocaine and wait for its effect. Then put on the clamp forceps, screw it tight, and inject hypodermically three drops of 4$ cocaine solution alongside the tumor. In a few minutes the dissection can be made painlessly and almost without bleeding. Most of the clamps have a broad plate of metal or horn for one blade and this is sometimes useful. A simpler form will usually answer. (See Fig. 93.) In lack of clamps, a flat spatula or the operator's forefinger slipped under it, will hold the lid tense and check bleeding; the tumor is to be ex- posed and may be seized with a sharp hook by an assistant and THE EYELIDS AND CONJUNCTIVA. 255 excised, or if without an assistant, pointed scissors curved on the flat will remove the projecting part, and when thus opened the re- maining portion can be scraped out. Should a small perforation of the lid occur, no harm is done. For very large cysts with thick posterior wall, it may sometimes be well to touch it lightly with a point of lunar caustic instead of relying on scraping alone. To guard against recurrences, remove chronic palpebral conjunctivitis and correct eye strain, and in some instances cod-liver oil and means to improve nutrition, especially if there be a strumous dia- thesis, are important. Phlegmon of the Lid. If suppuration occur in the connective tissue of the lid, as may happen after debilitating disease, or in strumous children, or with- >■ out recognizable cause, there will be great swelling, and fluctuation will be detected early. It may come with very little pain and but little redness. It is also important to remember, that a general inflammation of the lids may occur in delicate children, and not re- sult in suppuration: there may be great oedema and slight redness, and the whole may disappear by resolution. On the other hand, the connective tissue may become gangrenous in cachectic subjects. If suppuration occur, the pus must have vent early, by a free incision, parallel to the border of the lid. The best knife is a Beer's cata- ract knife, or a very narrow, sharp pointed and curved bistoury. Stand behind the patient, pierce the skin, and run the point along with a quick, steady thrust. The earlier the incision is made, the less will be the likelihood of deformity after the abscess heals. In cases of erysipelas of the face, if there be much induration of the lids, care must be taken to watch for suppuration. It is very liable to occur, and considerable destruction of tissue may take place, which early incision would obviate. In the severe forms of the disease, it sometimes becomes needful to make deep incisions when there is no evidence of pus, to save sphacelation of the tissue. A very remarkable and fortunately rare occurrence is sponta- neous gangrene of the skin of the lid. Two cases of this character were reported to the New York Ophthalmological Society by Dr. Rushinore, of Brooklyn, in 1883, and another by Dr. R. H. Derby in 1SS4. See case by Hilbert: Centralblatt fur Augenheilkunde, Oct., 1883, p. 293. Deformity will ensue for which a plastic opera- tion may be required. Inflammation of the Tarsus. Tarsitis.—This does not occur very often. It is usually syphili- tic, yet maj7 be simple or idiopathic. It is very slow in progress and not specially painful; it is attended by great thickening of the 256 DISEASES OF THE EYE. tarsus, abscesses are apt to form in its substance and they break at the tarsal border. Hence, there will be ulcers, crusts and yellow projecting points, the eye-lashes will fall and their follicles atrophy. It will appear like blepharitis marginalis, but the great thicken- ing of the tarsus declares its character. A diffuse redness spreads over the lid border and the appearance may be very unpleasing. If, as is usual, syphilitic, constitutional treatment will be essen- tial; if simple, it will be difficult to control. Hot fomentations may be applied and the stimulating ointments above mentioned, while in the case of a young lady whom I treated for over a year the only control over the minute abscess and the thickening, was by inserting a red hot needle alongside a hair, or passing in a platinum needle dipped in strong nitric acid. (See Bull, Trans. Am. Oph. Soc, 1878, p. 405.) All varieties of diseases of the skin may appear on the lids and the following may be singled out: eczema, xanthelasma, molluscum contagiosum, herpes zoster ophthalmicus. Eczema appears in the acute and chronic form. It is common among children in connection with acute conjunctivitis and kerati- tis, presenting crusts and ulcerations and discharge. The scaly and hypertrophic form appears chiefly among adults and especially in the aged. For the former, complete and careful washing away of scabs, and application of vaseline, or boric acid and vaseline, or yellow oxide of mercurj7 ointment, may suffice. But in many cases, especially among children of the poor, it is better to give chloro- form, remove the scabs, dry the bleeding with absorbent cotton and go over the surface with pure nitrate of silver. After this the above ointments will complete the cure. Starch powder may be dusted on the surface if needful. Commonly similar crusts exist about the nostrils and perhaps at the angles of the mouth; all such spots should be cauterized. Treatment of conjunctival inflamma- tion w7ill at the same time be attended to. The squamous and hypertrophic eczema may be limited to the eyelids and vicinity, and may or may not be complicated with acute conjunctivitis. If the condition be chronic, the stimulating reme- dies may be used, viz., Olei cadini, 1 part; vaselini, 2 to 4 parts; or the diachylon ointment (vide p. 253). In acute conditions with serous effusion and, as may happen, with the whole face involved and the conjunctiva acutely inflamed, the milder ointments of oxide of zinc, vaseline and boric acid, of white precipitate of mercury, or dilute citrine ointment are to be preferred. Wet applications are generally decidedly unacceptable. Sometimes the irritation is ex- treme and may call for bromides and preparations of opium or other anodynes internally, as well as hypnotics: antipyrine, gr. x.; hyoscyamine, gr. jfo or gr. -g^ in tablets, chloral, phenacetine, etc. THE EYELIDS AND CONJUNCTIVA. 257 Such astringents, as tannin and alum, are better for the con- junctivitis than nitrate of silver, and cocaine may be employed to advantage. Xanthelasma or xanthoma is a fatty degeneration of the con- nective tissue of the skin, which has a predilection for the eyelids, although it occurs elsewhere. Yellow or straw-colored, slightly nodular patches appear at the inner extremities of the lids, usually symmetrically, and both upper and lower lids may be affected. They gradually extend and may become large and prominent welts. They come oftener in women than in men and after middle life. They are easily removed by excision, which is the only mode of relief; but I have been disappointed to find the disease return within a year in one case. Being without danger and simply a slight blemish, few persons care to submit to their excision. Molluscum contagiosum appears anywhere on the body and often about the lids. The little tumors may be as large as peas or hempseeds. The top is cupped and a little opening leads into the middle of the tumor. The sebaceous glands are probably the seat of the disease and they contain altered epithelial cells and peculiar bodies called molluscum corpuscles which are of a fatty nature. The contents may be squeezed out between the thumb nails through the little opening above mentioned; or, if needful, they may be opened with a knife. Evacuation cures them. That they are con- tagious does not seem to be well founded. Herpes Zoster Ophthalmicus exhibits conspicuous and important features. It is called by the French zona ophthalmique, and has been extensively described by Hybord, and previously by Mr. Hutchinson. It is, in truth, a neuropathic affection having its cause in degeneration of the gan- glion of Gasser, or of the branches of the trigeminus, or of both. Any of the branches of the fifth pair may be thus affected, and the eruption appears along the distribution of the diseased nerve-twigs. It therefore happens that vesicles may occur on the eyeball as well as upon the skin, and both ulceration of the cornea, acute conjunc- tivitis and acute iritis may take place. It may even cause loss of the eye by irido-cyclitis. It is also said that small abscesses have been found in the ocular muscles. The mode of occurrence, as illustrated in a boy ten years of age, was as follows: the supra- orbital nerve was the one affected. The initial symptom was in- tense pain along this nerve at the supra-orbital notch, around the lachrymal sac and side of the nose, upon the forehead, and up to the vertex. In a few hours the skin of the forehead became red and swollen, tender to touch, and a few vesicles appeared above 17 258 DISEASES OF THE EYE. the inner end of the brow. While the right half of the forehead, red and swollen, presented the look of erysipelas, the left half re- mained natural. The hair could not be combed because the scalp was tender, and a few vesicles were there discovered. The eyelids swelled, a slight conjunctivitis appeared, chiefly affecting the pal- pebral surfaces, and there was great photophobia. The pulse was quickened; it reached ninety, and some febrile reaction occurred. The urgent symptom was the pain, which continued day and night. A few vesicles appeared on the side of the nose; none whatever showed themselves across the median line. The treatment consisted in keeping the boy in bed and dropping into the eye every two hours a solution of sulph. atropia, gr. ij. ad 3 L, to abate the pain (cocaine would have been proper), using upon the forehead hot fomentations without intermission, and giv- ing full doses of morphia and quinia sulphate three times daily. By the fourth day there was decided mitigation of the symptoms, but it was not until the twenty-fourth day that the patient could go out. No lesion of the cornea took place. In case the latter should occur, it would be much longer before the patient would be well. When there is an eruption on the cornea its surface is mark- edly anaBsthetic. This suggests a reason for the long continuance of the affection in some cases, and also the need of keeping the eye bound up so long as the irritation continues. The special treat- ment suitable to cases of ophthalmic shingles, in which the cornea or iris may be involved, will be found under the chapters which treat of these troubles respectively. I have seen one case in which, while one eye was destroyed by the direct mischief of the disease, the other was also lost through sympathetic irido-choroiditis. I have notes of a case in which both sides of the forehead were attacked. Permanent scars remain, which may be recognized by their rounded form, and by a slight depression of the surface. The disease may take place at any age, and it is most hurtful to the aged and feeble. It is very apt to be regarded as simple erysipelas, but from this it may be discriminated by the intense neuralgic pain following certain nerve-twigs, by the strict localiza- tion of the skin trouble, and by the vesicles. The lesion may go down to the tip of the nose, or upon any part of the distribution of the trigeminus. The treatment, as above specified, should be both local and constitutional, the latter being such as may control neu- ralgia, the former to soothe the local inflammation. For a severe attack in a man who was nearly eighty years old, ten-grain doses of quinine were given at intervals of two hours until fifty grains were taken daily, with marked benefit and perfect tolerance of the drug. It is said that when the vesicles appear on the nose, the cornea is most likely to be involved. I cannot support this state- THE EYELIDS AND CONJUNCTIVA. 259 ment because I have found the corneal affection both with and with- out implication of the nasal twigs. See cases by Jeffries and Mathewson, Trans. Am. Oph. Soc, 1874, pp. 221, 228. Mathewson used constant (?) galvanic current with great relief to pain in five cases. Severe optic neuritis followed by atrophy has been seen (Daguenet, Rec. d'Ophth., 1877, 177); paralysis of accommodation and mydriasis have been repeatedly seen. Syphilitic ulcerations are sometimes found upon the lids—they may be chancres or secondary ulcerations; although the latter are more likely to appear on the mucous surface. It is hardly neces- sary to say anything about the recognition and treatment of these conditions. They only need to be mentioned (see paper by Dr. Bull, Trans. Am. Ophth. Soc, p. 408, 1878). French literature furnishes the greatest number (see paper by Dr. Beck, Trans. Am. Ophth. Soc, 1886; who has collected 94 cases). Epithelial Cancer and Lupoid Growths are quite often situated upon and near the eyelids. A discrimina- tion between them is hardly needful for practical purposes. If a nodular, irregular elevation appears on the lid border, or on the skin, and is covered by a dark crust which, when picked off, exposes a bleeding surface, and if this continue for months or years, some- times healing and again breaking out, but never going entirely away, this neoplasm, although quite painless, had better be excised. The true epithelioma is more rapid in development than a lupoid growth, and both may result in ulceration. In either case the neighboring lymphatic glands are not likely to be enlarged, except at a late date. The gland which we look for is that in front of the tragus—the pre-auricular gland. Grow7ths such as we are now considering, occur during and after middle age, and usually remain unheeded for a long time. Sometimes soothing lotions will pro- cure healing of the ulcer. The solution of chlorinated soda (Labar- raque's), diluted with five parts of water, will often be followed by perfect cicatrization of a suspicious and extensive ulceration. It is applied for twenty minutes by a piece of lint six or eight times a day. I have made this observation many times during the last fifteen years. For almost all cases, the best method of treatment is an opera- tion, and not caustics. If the latter be applied to the lids, deformity will follow which will necessitate an operation, while if the knife be resorted to, the deformity ma}7 be at once remedied by a suitable plastic proceeding. If there be a spot of ulceration on the cheek or temple or nose, covered with a thin brown crust, which leaves, when removed, a bleeding depressed surface; if, too, the skin be hard and infiltrated at this spot, the case is probably lupus non 200 DISEASES OF THE EYE. exedens. Scraping out with a sharp spoon, or thorough burning by actual cautery (Paquelin's thermo-cautery) will be likely to cure it. Escharotic plasters are to be eschewed; they cause great pain and wide destruction. In many instances of probable epithe- lioma upon which I have operated, there has been no return of the disease for man}- years. The prognosis is encouraging when a thorough removal is performed. If a relapse demands a second operation, even then, as I have seen, the disease may not recur. I have seen one case of amyloid tumor upon the border of the lid. The patient w7as a young woman under the care of Dr. Prout, of Brooklyn. Papillomata or warts are not uncommon on the border of the lids. They may be snipped off, or accurately touched with nitric acid applied by a platinum probe, or by a small and pointed stick. Horny growths have been known to occur on the lids. One in- stance I have had in my own practice. Milium presents a perfectly white tumor, not larger than the head of a pin. It is a retention tumor of a sebaceous follicle and simply needs puncture. For an account of very rare cases of adenoma of the Meibomian glands and of the glands of Krause, see Salzmann, Arch, filr Ophthal., XX., 3, p. 380, 1891. Njeyi and Teleangiectatic Tumors. Several varieties of vascular growths occur on or about the lids; they may be simple red patches, or slightly elevated and flattened patches, or they may be conspicuous and lobulated masses contain- ing large vessels as well as capillaries, and are called cavernous tumors. The diagnosis is simple and no extended description is required. Treatment.— Excision is advisable in the early stage of these tumors, and the lid clamp of Snellen or Knapp can often be used to check bleeding. Destruction of the tissue may be effected by punc- ture with red-hot needles (shoemakers' sewing awls are sometimes convenient). The dental blast lamp gives the requisite heat, if a Bunsen's gas burner or large alcohol flame does not suffice. A suc- cession of operations will be required. For a considerable number of tumors excision ma}7 be successfully practised, because they will be found inclosed in a distinct fibrous capsule, and if this be re- spected, no serious hemorrhage will occur. Care must afterward be taken to keep the cavity well closed and to treat it antiseptically. For certain large growths which may perhaps extend into the orbit, electrolysis offers a sufficiently safe and effectual method. The purpose is to coagulate the blood, not to destroy the tissue. A number of needles connected with the positive pole may be THE EYELIDS AND CONJUNCTIVA. 261 plunged into the tumor and the negative pole applied by a sponge to the temple. The needles should be of platinum to prevent oxi- dation. The current must not be strong, usually four small cells suffice. See Figure 230, under chapter on the Orbit. In all operations care must be taken not to excite severe re- action lest deformity ensue. I have seen a case in an infant for which the common carotid had to be tied. The tumor disap- peared. Injection of persulphate of iron is too severe, of alcohol has been lately recommended. Threads may be run through to excite sup- puration. In some instances small and even large vascular tumors have been known to disappear of themselves. Minute vascular growths, like little red warts, sometimes appear on the border of the lid. They may be easily tied or burnt off. Moles or brown patches may occur congenitally either upon the lids or in the neighborhood. They should be excised, and after- ward a proper plastic operation performed. I was called upon to do this for a young lady, whom I saw again after several years, and found that similar pigment-nodules had appeared upon the neighboring skin which had previously been healthy. The primary growth was congenital, was set with stiff hairs and seemed to be innocuous, although a decided blemish. The subsequent pigmenta- tion showed no malignant or ulcerating tendency. Diseases of the Eyelashes. They may fall out as the result of chronic marginal blepharitis, and when one of the symptoms of secondary syphilis without any noticeable inflammation; while at the same time the eyebrows will be shed. The condition is called madarosis or tylosis. Canities is the name given to decoloration of the lashes. There may be a cluster of white cilia on only one eyelid. I have seen all the cilia of one lid perfectly white and the cilia of the remaining lids dark; in the same lady there was a wisp of white in the midst of the dark brown hair of the head. Phtheiriasis signifies the presence of crab lice (pediculuspubis) among the lashes. Their eggs adhere in rows to the cilia, and the crawling of the creatures provokes itching. Mercurial ointment destroys them, locally applied. Distichiasis means that there is a double row of lashes, one of which touches the globe. As many as two displaced rows have been seen. As a rarity the condition is congenital, usually it is acquired. Trichiasis differs from the above in the irregular position and shape of the lashes which come in contact with the eye. A few or a j?reat number may be inverted, and they curl in various direc- 262 DISEASES OF THE EYE. tions. Many of them will be atrophied. There may be thickening of the tarsal border, but the tarsus is not bent or notably deformed. The state of the tarsus makes the distinction between trichiasis and entropium, although the former insensibly shades into the latter. Trichiasis is caused by blepharitis marginalis, by tra- choma, by burns, etc. We may practically distinguish between partial and complete trichiasis. Either the upper or the lower lid may be affected and the effects upon the cornea may be more or less severe. Treatment.—For partial trichiasis the methods available are 1, epilation; 2, snaring them with a thread; 3, destruction by hot needles or by electrolysis; 4, excision of the follicles. Spasm of the orbicularis and conjunctival irritation often coexist and if the bor- der of the lids be forcibly inverted, spasmodic entropium. 1. Pulling out the hairs by forceps gives temporary relief and must be repeated every week or two. Often the offending lashes. are very fine and difficult to seize, and a patient will much complain if the " short hairs " are overlooked. After operations some errant cilia may remain and their evulsion be preferred to any other pro- ceeding, and will often be done by some member of the family. 2. Ensnaring the cilia in a loop of thread (Snellen) is done by entering a needle, through whose eye both ends of a fine silk thread have been passed, and as the loop is drawn to the base of the hair,, the latter is put within it and dragged up into the substance of the lid. This proceeding applies to single or a very few hairs. A thread may also be used to destroy a group of hairs by carrying it into the substance of the tarsus up, across, and then down, inclos- ing them in its bight, and tying down hard upon the lid border to crush the follicles and set up destructive suppuration. 3. Destruction by red hot needles, by a platinum needle dipped in caustic potash, or by electrolysis is better suited to the above con- ditions. The last was proposed by Michel, of St. Louis. A trian- gular gold or platinum needle is pushed into the follicle and con- nected with the negative pole of a constant battery of from eight to twenty elements; the sponge of the positive pole is placed on the temple or held in the patient's hand. When the circuit is closed, minute bubbles of gas are disengaged and the tissue whitens about the base of the cilium. There is considerable pain and about a minute is needed to destroy the follicle. The treat- ment sometimes fails. 4. Excision of the follicles is done by taking out a rectangu- lar portion of the tarsus, without encroaching on the Meibomian follicles. The superjacent skin is dissected up in a little flap, and this may be extended upward, and after the removal of the bit of tarsus the flap be dragged clown, its tip cut off, turned in to cover the lid border, and held in place by a suture at each corner. Slight THE EYELIDS AND CONJUNCTIVA. 263 traction is thus maintained and the gap is filled up (Anagnostakis). When trichiasis is more extensive, the mode of proceeding will depend upon collateral conditions. As already said, the cases merge insensibly into those called entropium, there being in both classes lesion of the tarsus, but in the latter it is more severe. The choice of method will depend upon the length of the palpebral slit, the quantity of substance in the lid, and especially on the state of the tarsus. It is convenient to deal with the subject under the head of en- tropium and indicate what modifications of method are suited to varying morbid conditions. Entropium. Besides simple inversion of the lashes, we find in old cases shortening of the palpebral slit, thickening and incurvation of the tarsus, as readily seen by the furrow along its middle when the lid is turned over, the tarsal border becomes sharp and thin, and often the lids hug the eyeball tightly. This last circum- stance produces almost as great mischief as the presence of the inverted lashes, by fretting the cornea and keeping up the super- ficial inflammation. The effect of entropium is, opacity of the cornea, and if the lids are tight, the softened structure loses its proper curve and may even become staphylomatous. Entropium may appear during the progress of trachoma, but is usually one of its sequelae, as will be hereafter described. We have, besides the cases above referred to, two other forms of entropium, viz., the senile and the spasmodic Senile entropium ensues from relaxation of the tissues. The skin becomes folded and droops, and the ciliary border turns inward, the orbicularis aiding in the effect. For relief of the senile variety, the removal of a properly pro- portioned piece of skin is all that is usually required. Threads run vertically beneath the skin and tied tightly down to cut their way out and reef up the tissues by the cicatrices, are objectionable from the puffy state in which the parts are left. It is easier to effect the object in the upper than in the lower lid. Entropium of the lower lid often complicates the treatment of cataract extraction, being both spasmodic and due to relaxation. Sometimes a piece of caoutchouc plaster or the application of contractile collodion will draw the lid down, but generally a portion of skin will need removal. This will run parallel to the border and vary from six to twelve millimetres in width. Spasmodic entropium of the lower lid happens in chronic kera- titis and in other conditions. A suitable operation for an obsti- nate case is indicated in the diagram (Graefe), (see Fig. 94), 264 DISEASES OF THE EYE. where the flaps being undermined, are brought together over the open wound. For a case of trichiasis at the outer third of the lower lid with entropium which was maintained by tracho- matous cicatrices of the conjunctiva I did the following: At four millimetres below and parallel to the lid, I raised a flap about six millimetres wide and equal in length to the lid. It was left attached at its temporal extremity and about one-half of it cut off. The remaining piece was trimmed and turned up to be imbedded in the lid border where the erring lashes grew, and stitched fast. Like a piece of tape it held the lid in permanent eversion. The wound below the lid border was closed by sutures. The girl disappeared from view for seven years after the parts healed. I then cut away the bridge of skin. The deformity was cured, the cornea was healthy, and no return of the trouble took place. Probably a month would have sufficed to effect the object. Still other methods of dealing with these cases exist, as by su- tures. (Saemisch, Wecker.) The methods of treating ordi- nary entropium are almost in- numerable. One must make choice according to the needs of a given case. It must be remembered that its essential cause is deformity of the tarsus and all operations must be adapted to modify and correct its malposition. The operations of Arlt, Jaesche, Flarer, and others begin by splitting the tarsus along the border into two layers for a depth of about three millimetres, and the ciliary border is drawn up after ex- cising a narrow strip of skin above it. Another proceeding is not to throw away the strip, but to leave it attached at each extremity, to draw it by the middle below the ciliary flap, and make it take the place of the latter on the lid border (Gayet, Dianoux1). Sw7an- zey figures the operation, but it hardly seems possible to avoid a clumsy and unpleasing result by such a device. Where no serious deformity of the tarsus exists, Arlt's method of transplantation of the loosened lid border, which is well known, serves an excellent purpose. If the incisions inclosing the semilu- nar flap are carried a little beyond the outer and inner canthi, in- verted lashes at the extremities will not be omitted in the effect. The excised flap of skin will be from four to six millimetres wide at its middle. The displaced marginal strip will be about four milli- metres wide and may or may not be fully loosened at its upper Fig. 94. 1 Annales d'Oculistique, 1882, xxxviii., p. 132. THE EYELIDS AND CONJUNCTIVA. 265 ■edge. The exposed surface at the margin of the lid is left to gran- ulate. It is better to depend on a spatula by which an assistant lifts the lid and keeps it tense, than upon a clamp. It restrains bleeding sufficiently. Acting upon another principle are the methods of Streatfield, Snellen, Pope, in which a deep groove is cut into the tarsus on its front surface just above the lid border, or the tarsus substantially dissected out; a strip of skin with subjacent muscular fibres is next removed, and the wound closed by sutures. A canthotomy may also be done. These proceedings are suited to cases where shrink- ing of the tarsus has begun, yet not advanced very far, and w7hile often effective, more confidence can be placed upon another opera- tion devised by Dr. John Green which will be presently described. Mention must be first made of Hotz's operation, which is care- fully described in Knapp's Archives, 1879. The theory of it con- sists in making the integument so adhere to the upper edge of the tarsus and the tarso-orbital fascia, that its tension shall draw the ciliary border outward. (See Anatomy, page 247.) The mode of performance is as follows: an assistant fixes the skin of the brow against the orbital edge, the surgeon draws down the lid at its middle with his thumb and finger or by forceps, he incises the skin horizontally along the whole length of the lid on a line which begins and ends two millimetres above the outer and inner canthi. The lid being stretched and drawn down at its middle, this line, although made horizontally, becomes a curve when the lid is let go, parallel to the upper border of the tarsus. The as- sistant pulls down the lower edge of the wound with forceps and the operator thoroughly dissects off the muscular fibres which cover the upper third of the tarsus. When bleeding stops, black sutures, three or four, are inserted by a curved needle through the skin at the lower edge of the wound, then through the superficial fibrous tissue of the upper part of the tarsus and made to dip into the aponeurosis just above its upper edge and finally emerge through the skin at the upper side of the wound. An assistant draws up this edge meanwhile. No muscular fibres must be in- cluded. The loop, when tightened by a surgeon's knot, draws the skin both above and below to the upper border of the tarsus and the aponeurosis, and fastens it down upon it. A lever action is thus exerted wrhich tips up the ciliary border. Unless this effect ensues, the method has not been correctly followed, or the tarsus has undergone so much distortion as to make it inapplicable. Con- siderable reaction follows: the sutures remain in situ two days^ never more than three, for suppuration must be avoided. Some- times, when very redundant, a narrow strip of skin is removed, but usually this is needless. It may be requisite sometimes to simulta- neously perform canthoplasty. See Fig. 95. There is no doubt 266 DISEASES OF THE EYE. about the great value of this method, and it shares with Green's operation well-deserved confidence. Its fundamental idea was em- bodied in an operation by Anagnostakis in 1857, but less satisfac- torily than by Hotz. With Green's1 operation my own experience has been highly satisfactory. The lid is everted and held by the fingers, and an incision made through the entire thickness of the tarsus upon its conjunctival side, parallel to the lid border and about two millimetres above it, and extending from end to end. A round - pointed scalpel is used by Green. I usually take a Beer's catar- act knife and push the point through. Next a strip of skin not more than one and a half or two millimetres wide is removed along a line about one and a half millimetres above the cilia. Muscular fibres are left intact, to aid in maintaining by their vascularity the vitality of the lid border. By a curved needle A (see Fig. 96), the sutures are carried out as shown in the diagram from the conjunctival side of the cilia through the free edge of the tarsus just above the lower border of the skin wound. The thread is drawn through, the needle re- entered through the muscular fibres upward along the outer surface of the tarsus, at the point B, going in deeply, and emerges about one centimetre or more (about half an inch), higher up, through the skin. When the sutures, usually three in number, are tied, the skin wound is closed and the ciliary border is everted. An additional security, on which, in my experience, great stress is to be laid, consists in turning the eyelashes back upon the skin and holding them down by collodion spread upon a few fibres of cotton laid parallel to the lid border. This dressing of cotton fibres and collodion rigidly holds the lashes in the desired position, closes the wound hermetically, and permits in many cases the withdrawal of one or more sutures when the collodion is dry. All sutures may be removed in twenty-four hours and a fresh dressing of collodion and cotton applied. The tarsal wound gapes widely and fills in a few days with granulations. Cantho- plasty may be combined with the operation. Fig. 95.—Represents a Vertical Section of the Upper Eye-lid. s, supra orbital margin; to, fascia tarso-or- bitalis; po, pars orbitalis; pc, pars ciliaris of orbicularis muscle; £, tarsus; c, »»ye-lash; /. lower border, a, upper border of the wound; a, b, passage of suture through aponeurosis. • Trans. Awer. Ophth. Soc, 1880, p. 167. THE EYELIDS AND CONJUNCTIVA. 267 Green's operation is suited to cases of all grades. It does not involve risk of sloughing of the ciliary border as sometimes happens with Arlt's operation. Hotz's operation is available after other methods have failed of success and especially if, as too frequently happens, considerable skin has previously been removed. It can be applied to the lower lid, but should not be done upon both upper and lower lids at the same sitting, because reaction would be severe. From Green's operation little reaction ensues, and it likewise is. effective on the lower lids. A choice between these two methods, which in the writer's view are superior to all others, is to be de- cided by the peculiarities of a given case and by the preference of the surgeon. Very many methods besides the above have been devised and are figured in text-books. Among them Snellen's is certainly good, but the writer finds those described adequate to all needs. He may be allowed, however, to men- tion a proceeding once employed in a desperate case, where great shrinking and shortening and tightness of the lid, from which all lashes had been re- moved, produced by its friction extreme vascularity and opacity of the cornea with distortion of its curve. Various operations had been done. The in- dication was to loosen the nip of the upper lid. The forefinger was pushed under the lid to the top of the scanty conjunctival sac. A narrow knife was thrust under the skin on the middle line of the lid flat-wise and when the point had got above the upper border of the tarsus the edge was turned to- ward the operator's finger and the point caught in the nail, then in drawing down, the tarsus was split in the vertical line into two halves and they sprang asunder several millimetres. The pressure on the cornea was relieved, no deformity ensued, for the skin was not cut, and many months afterward the cornea continued free from vascularity and irritation. The total ablation of the ciliary border has been formerly much practised, and it may in extreme cases be appropriate; but " scalp- ing the lids " leaves hopeless deformity and is a slur upon surgery. Only absolute necessity justifies its employment Ectropium. Permanent eversion of the lids arises, 1st, from chronic in- flammation and hypertrophy of the conjunctiva, especially of the lower lid in old persons—a condition due to relaxation of the skin with spasm of the orbicularis muscle. It sometimes occurs during recovery from operations, as well as spontaneously. Treat- ment consists in excising a suitable strip of thickened conjunctiva close to the ciliary border, and perhaps removing a V-shaped por- tion of the lower lid at the outer canthus, to draw the lid up to the globe as well as to replace it. The excision at the outer angle is only needed when the lid droops and the amount removed will de- pend on the degree to which it falls. Sometimes the destruction of '268 DISEASES OF THE EYE. conjunctiva by Paquelin's cautery is all that is required, and the slough is left to separate. No bleeding happens and by the help of ■cocaine, 10$ solution, the operation is very simple and easy. A fine point must be used and a deep furrow made. The second and more fuequent type of ectropium is caused by wounds, by burns, by caries of the edge of the orbit with adhesion of the skin, by removal of tumors, etc. The amount of deformity is extremely variable and after burns and explosions may be frightful. The following general suggestions in treatment are appropriate: While some kind of operation will be required, none which involves transplantation of skin should be done, until all tendency to con- traction of cicatrices has disappeared. While ulcerated surfaces are in process of repair, no operation is feasible, except the intro- duction of a flap either with or without a pedicle. Usually we wait until healing has occurred. The exceptions will be after severe burns. Yet it might sometimes mitigate deformity and protect the cornea, to pare the edges of the upper and lower lids behind the cilia and stitch them fast, so as to obliterate the palpebral slit, save at its extremities. The tendency to ectropium would in some measure be thus counteracted until healing had become complete and con- traction of scars had done its worst. It is easy to separate them when the time for operation arrives. Scars of moderate extent will yield to persistent traction; if attached they become looser and stretch. Subcutaneous division will not release them, because adhesion will be re-established; but it may render traction more effective. In a case of great deformity by loss of a large portion of the lower edge of the orbit at its temporal side, the deep hollow was suc- cessfully filled by inserting a thick flap shaped like a finger from the temple and covering it over by the thin integument of the diseased locality. An incision was made parallel to the border, the skin undermined freely and united by sutures above the buried flap. Union was satisfactory. Certain general rules are to be observed in plastic surgery. Adherent scars should be excised, or they should be buried under a flap of skin; if not, adhesion will return. Scar tissue should not be included in a flap unless the scar is very superficial and the true skin has not been destroyed. An apparent exception is in the case of the Wharton Jones sliding flap, where the whole ciliary border furnishes vascularity, yet sloughing of the tip of the flap is the risk of the proceeding. The existence of a syphilitic dyscrasia is preju- dicial to success. I once met a sad disappointment in a young girl who from hereditary syphilis had lost the nasal bones; attempting THE EYELIDS AND CONJUNCTIVA. 269' to make a new nose by flaps from the cheeks, the wounds showed no disposition to unite and underwent a torpid and unhealthy process of suppuration; the flaps shrivelled and the condition was worse than at the first. In constructing and placing flaps, allowance must be made for shrinking, which will amount to about one-fifth in length, and further shrinking will occur after the healing. Lines of union must be so planned, if possible, as not to reproduce the deformity as shrinking of the flaps slowly proceeds, but act in the contrary manner. Again, flaps will sometimes grow thicker during subsequent weeks if they be very loose. In plastic surgery of the face, one must fit parts as a tailor fits his cloth and not fear to cut out redundant material or to smooth down elevations. By a little ingenuity puckers and welts need rarely be left. In ectropium the ciliary border will be elongated and must often be shortened, and this is done by excision of a triangle of skin whose base is at the free border of the lid and preferably at the outer angle, while sometimes it may be done at the middle. The operation to be performed in a given case will of course depend on the conditions to be met, and each case must be studied by it- self. Wounds at the inner angle dragging down the lower lid are difficult to repair perfectly. In such a case as is shown in Fig. 97 the scar on the side of the nose should be undermined, the lid fully loosened and lifted higher up, a portion excised and the cut edge joined to the inner canthus; then to fill the gap a flap may be brought from the forehead with pedicle at the root of the nose and by properly managed lines, very little wrinkling need be made: vide infra. A small flap could be had beneath the brow. In both cases the base of the flap is above, or at any rate not below the site of the gap, and contraction tends to correct deformity. In such a case a flap from the side of the nose would be unfeasible be- cause the part beyond the cicatrix would slough. The sutures must be very fine and numerous and the skin thin. Fig. 98 shows ectropium of the outer part of the lower lid by cicatrization without adhesion to the bone. The mode of operating is clearly indicated. It will be noted that pin sutures are used. They should be very fine, be inserted well back from the wound, and are strongly to be commended. In the dissection of the flap and in bringing together the gap below the lid, the skin must be 270 DISEASES OF THE EYE. freely undermined on all sides. The cutaneous incision may be ex- tended right and left close to the border of the lid. The same pro- ceeding may be applied at the outer canthus and the lines be Fig. 98. Fig. 99. made more oblique outward and downward. This is a most im- portant suggestion. (See Fig. 99.) Another principle applies to more extensive deformities of this kind, both in the lower and upper lids. It is the operation of Whar- ton Jones, who intended it for the upper lid. (See Figs. 100 and 101.) The length of the flap is determined by the degree of deformity, and its dissection toward the conjunctiva must not be carried too far lest sloughing occur. In the figures the dissection does not go as far as it might. It is suited only to cases of moderate degrees of ectropium, and is to be chosen when the skin has not been deeply burned. The insertion of flaps is advisable for the greater degrees Fig. 100. FlG. 10i. of deformity. Von Ammon figures the same method on a larger scale. I must again repeat the caution that the method must not be pushed too far. There are many devices which may be employed in dealing with THE EYELIDS AND CONJUNCTIVA. 271 ectropium. A most ingenious one involving the formation of two flaps, one of which fills the opening made in bringing the lid border to its place, and the other fills the vacancy whence the first flap was dissected, we owe to Richet. It meets cases of caries at the outer edge of the orbit, resulting in dragging down the outer can- thus besides ectropium of the lower lid. To supplement it, the edges of the lids are pared and sewed together, not, however, de- stroying the cilia. See Meyer on Diseases of the Eye. Blepharoplasty. The transition from restoration of the lid by some method of displacement to its reconstruction by introduction of new skin, is most natural. Many cases of ectropium require the latter method, and for its accomplishment we may, 1st, use a flap from the adja- cent parts kept in connection with the general circulation by a pedicle; 2d, we may transport a very thin piece of skin from a re- mote part and apply it in a wound (Wolfe's method); 3d, we may make use of small bits of skin, grafting them into the wound as a mosaic, the method of Reverdin; 4th, we may put in a thin shaving of skin by Thiersch's method. The last two methods are suitable where the skin has been widely destroyed and healthy material for flaps is not available. They can also be happily employed during the granulation stage of burns to prevent or mitigate deformity. Partial closure of the lids by tarsoraphy may simultaneously be resorted to. The pieces (Reverdin) must be thin, say about two millimetres square, and as numerous as occasion demands. When in place they should be covered with gold-beater's skin, over this a pad of lint, and all held firm by plaster or a bandage. The outer dressings may be removed once daily, and the state of the grafts will be seen through the gold-beater's skin. They take on a white, sodden appearance, then become red and seem lost in granulation, but soon a healthy cica- trix, i.e., epidermis appears. The proceeding may be repeated. Analogous to grafting is the transplantation of a considerable piece of skin from a remote part. This proposal emanated from Mr. Wolfe, of Glasgow, 1875. The skin may be taken from the chest or the inner side of the arm. A pattern the size of the place to be filled, is to be laid down, and the outline of the piece to be transported must exceed it by eight to ten millimetres all around. Subcutaneous connective tissue is to be completely removed and this is most easily done while the piece is being lifted. When put in situ all bleeding must have stopped and fine sutures introduced; cover it with gold-beater's skin, then with collodion, and over all cotton or a bandage. The parts must not be disturbed, although 272 DISEASES OF THE EYE. the bandage may be taken off in two days. The gold-beater's skin and collodion will remain unchanged for many days. The epider- mis comes off and the piece looks very white; sometimes it becomes red, moist, and like ordinary granulation tissue. It at length as- sumes a firmer character and may correct the deformity. Such material is, however, subject to an extreme amount of contraction. A flap 3^ inches long by If inches broad has after three months been reduced to 1| x f inches. The tarsal margins may be united for several months to counteract the shrinking. It is both inter- esting and surprising that in so many instances (at least twenty are recorded) the flap survives and gives desired relief, yet it some- times sloughs, as twice has happened in my own experience. The conditions of health are extremely important, and that the flap be free from fat and connective tissue, that it fit accurately, that no hemorrhage shall occur beneath it, and that it lie absolutely undis- turbed for a week. If the operation fail, some other method may be tried, or it could even be repeated. The place from which the skin is taken may take several weeks in healing. The flap, accord- ing to Thiersch's method, is less liable to shrink, because the shav- ing is thinner, being taken by a razor, and is no more prone to slough. It is more simple. In a large class of cases, particularly where neoplasms are re- moved and more or less of the lid is sacrificed, other methods for im- mediate repair must be employed. Without attempting to describe all the possible ways of meeting difficulties, certain proceedings will be illustrated which have been found effective in my own experience. There are several situations from which flaps may advantageously be taken: 1st, from the temple; 2d, from the forehead on the median line; 3d, from the side of the nose, the naso-buccal flap. All these are available for both the upper and lower lids. 4th, a flap may also be taken from the region in front of the ear, whose base shall be above and near the zygoma. This is in a direction opposed to the course of the blood-vessels and in so far is disadvantageous, yet if necessity compel, it may be employed. A vertical flap from the temple whose base is below, may be allowed to run a little distance into the hair, and the hairs will to a great extent fall out and dis- appear by obliteration of the follicles. Sometimes the place from which the flap is taken, in the temple for instance, cannot be closed by sliding the adjacent skin—in the scalp this is easily remedied by moving forward a second flap to fill the gap, and the vacancy thus caused may be left to granulate. The scar which results is pushed so far back as to be covered by hair and be unobjectionable. Even on the face this device may sometimes be practised. A flap from the temple, when designed for the lower lid, should THE EYELIDS AND CONJUNCTIVA. 273 be more or less vertical and the pedicle be a little higher than the level of the lid. The cut on its lower or anterior side should run farther back and down than on the upper, and if much of a wrinkle occurs in turning it down, a triangle may be excised, and sufficient breadth of pedicle is to be allowed to permit it. Small trimmings should always be done at the time of operating, and ex- tensive undermining practised to liberate the neighboring integu- ment. The shortening of a flap after being lifted will usually amount to about one fourth its length. Accurate coaptation by numerous very fine black silk sutures and by fine pins, so-called insect pins, where any tension occurs is indispensable. All bleed- ing must first be staunched. The lines of union may be covered with contractile collodion mingled with fibres of absorbent cotton, which makes an air-tight, inflexible dressing of the utmost value. Adhesive straps are wholly needless. I never use iodoform and, if antiseptic dressing is required, depend on absorbent cotton soaked with sublimate solution 1: 3,000, retained by a flannel bandage; it is kept constantly wet and need not be renewed oftener than twice in twenty-four hours. Sutures are allowed to remain three to seven days; pins to be removed on the second or third day. If any ten- dency to suppuration appear about the pins or sutures, remove them, wash well with sublimate solution, and either continue to apply it, or sometimes the collodion and cotton dressing may be reapplied. If at an early date the wound reopen for a short space, insert a silk suture. Such are some of the suggestions suited to all plastic operations. Another mode of forming a lower lid is by horizontally sliding a flap forward, from the region of the zygoma (Knapp), and it may if needful, be met by one from the side of the nose. An instance is represented in Figs. 102 and 103. The divergence of the lines of in- cision at their base is very important. The case was one of can- cerous growth. The naso-buccal flap is proper for repair of the inner portion of the lower lid, and less satisfactorily for the upper lid. If the tissues are very loose, a considerable loss of substance can be repaired at the nasal side of the lower lid without making any flap. In Fig. 104, page 275, excision of an epithelioma removed the inner half of the lower lid and skin over the region of the lachrymal sac. The deficiency was supplied by merely sliding up the cheek which was very lax. A vertical cut was made down to the ala nasi along the naso-buccal furrow; an incision close to the border of the lower lid was carried horizontally backward almost to the root of the zygoma. The whole cheek was undermined, taking care to avoid the duct of Steno, and carried forward and inward and at- tached to the inner canthus. No conspicuous scars were left. 18 274 DISEASES OF THE EYE. The photograph was taken very soon after recovery, before swell- ing had subsided. Sometimes the incision backward may begin at the outer canthus and the remaining part of the lower lid be carried inward with the loosened cheek. Free division of the external can- thai ligament must always be practised when the lid is slidden. If the inner part of the upper lid is also involved, we must take a flap from the glabella, or may slide one across the root of the nose, relying on the vessels of the other half of the face. Figs. 106 and 107 represent a case before and after operation where slid- Fig. 102. ing the cheek inward and upward was combined with a flap turned down from the glabella. The ultimate result was comely. I once combined the operation of sliding the cheek with the intro- duction of a transported flap (Wolfe's method) to fill the lack at the inner part of the upper lid, but the piece sloughed and I was obliged to slide a flap from above the root of the nose. The naso-buccal flap can be made to form an upper lid. See figures illustrating case reported in "Trans. Fifth International Congress of Ophthalmology," 1876. (See page 277, Figs. 109 to 112.) A flap from the middle of the forehead can be utilized for the upper lid and for defects at the inner canthus and of the inner part of the lower lid. Fig. 105. represents a case where epithelioma had Fig. 103. THE EYELIDS AND CONJUNCTIVA. Fig. 104. Fig. 105. Fig. 106. Fig. 107. 276 DISEASES OF THE EYE. attacked the region of the inner canthus and begun to penetrate the orbit; the inner half of the lower lid, the caruncle and inner third of the upper lid had to be removed. The flap taken from the forehead was so arranged that its base was laid upon the opposite side of the root of the nose; the arterial supply coming from the trochlear branches and angular artery of that side. Before it was sewed down the wound in the forehead was closed after undermin- ing the skin freely, the brow7s wrere slidden to each other, the gap in the upper lid was easily closed, and then skin was removed to make a bed in which the flap could lie smoothly and with- out traction. By carrying down the incisions for the flap to the opposite side of the na- sal bones, the objectionable wrinkling of the flap is entirely avoided and it lies so smoothly that it is hard to be detected after a few months. This man was exempt for five years from a return of the disease, but now, seven years afterward, it has reappeared extensively and entered the orbit. How such a flap may serve for the upper lid is shown in Fig. 108. The photograph was taken seventeen days after the operation and the same plan of reaching across the nose can be recognized. The relief was com- plete. The ectropium had been total and had lasted nine years. Various other methods must be resorted to as exigencies arise, and they are described in text-books, but I have stated the means on which I rely. Blepharophimosis, or narrowing of the palpebral opening, is generally the result of chronic trachoma. Its hurtful effect is by pressure of the lids on the cornea, and it is to be relieved by two methods of operating. The more usual one consists in splitting the lids apart at the outer angle and releasing them from their attach- ment to the bone by clips of the scissors through the canthal liga- ment, and finally uniting the conjunctiva to the skin by three fine sutures. This is canthoplasty as designed by Von Ammon, and it is often done as auxiliary to operations for entropium. Instead THE EYELIDS AND CONJUNCTIVA. 277 Fig. 109. Fig. 110. Fig. 111. Fig. 112. Fig. 109.—The man's head and face had been burned by kerosene oil. There were numerous ulcers in the scalp and on the forehead and such deep cica- tricial tissue on the forehead that the best available material was by the naso- buccal flap. The blood-vessels to nourish it were chiefly those from the op- posite side of the median line. The ectropium of the upper lid was complete, and the flap had to be about four inches long. Besides inserting the flap and uniting the gap in the face, the edges of the upper and lower lids were fresh- ened by paring their edges behind the cilia for two-thirds their length and then uniting by sutures. Primary union was obtained to a sufficient degree and the cornea was covered. As seen in Fig. Ill, considerable thickening and irregularity remained, which was greatly remedied by a subsequent operation. Had not the lid borders been united, the deformity would have largely re- turned. Many months after, the appearance was seen in Fig. 112. The outline of the incisions is shown in Fig. 110. A shorter flap will sometimes suffice, but the incisions are the same in all such cases. The dotted line under the lower lid shows how far this cut was carried, and the whole cheek was laid back. The tip of the flap was cut off to give it proper shape. 278 DISEASES OF THE EYE. of cutting the lids apart with scissors, it is better to separate them by a speculum and push a Beer's cataract knife or Aery narrow bistoury into the edge of the lid at the outer angle, splitting up and down along the border, and then cut the skin in a straight line out- ward, but leave the conjunctiva undivided. The external canthal ligament will be severed by a few strokes of the scissors to free the lids, and then the conjunctiva united to the skin. In very severe cases of shrinking of the conjunctiva with blepharophimosis and perhaps with entropium, a plastic operation may be needed and this I have called canthoplasty, while the above operation might be known as cantholysis. The lids are split apart for half an inch and a flap, with apex upward, is inserted; to obvi- ate wrinkling, the cut is extended downward as required, both on the anterior and posterior sides. Tarsoraphy, or the uniting of the edges of the lids, has been re- ferred to. It is called for in total paralysis of the facial nerve including the orbicularis muscle, and may unite one-third of the length of the lids at the outer angle. Complete union of the edges of the lids is done as an auxiliary sometimes to operations for ectro- pium. The method is simple, viz., paring off the posterior angle of the tarsal borders by a Beer's cataract knife and uniting by stitches. If the lids are to be again separated, a point must be left ununited. Injuries and Lacerations of the Lids. Powder burns occur by accidents in blasting, and may be com- plicated with other and extensive injuries, as we find among miners; boys often suffer the penalty of playing with gunpowder. The pain and inflammation are relieved by cold lotions, while the removal of the unburn t powder is to be effected by patiently picking out each little granule with a spud or cataract needle. The process is tedious and rather painful. Much of the powder will come out with the desquamating skin, while what lies below the epidermis must be picked out bit by bit, soon after the burn is produced. Blistering after the skin has recovered, has been suggested to bring out the remaining granules, but it does not seem promising. Lacerations and wounds through the tarsal border may, when fresh, be easily united by putting a fine pin through the free border of the tarsus, carefully stitching the conjunctiva and putting in the skin as many silk sutures as needful. Over all apply the collodion cotton dressing. If the injury is old and the parts have healed, perhaps, with ectropium, the edges of the cut must be freshened, the normal position restored, and the same treatment adopted. (See Fig. 113 from Lawson; a probe is inserted in the canaliculus.) A case recently under treatment is illustrated by Fig. 114. An THE EYELIDS AND CONJUNCTIVA. 279 Italian was cut in the face by a razor. The wound involved the border of the upper lid, split the cornea and passed down through the lower lid three inches upon the cheek. The wound of the face was sewed up before he entered the N. Y. Eye and Ear Infirmary. There was prolapse of the iris and the lens was partially cataract- ous. The prolapse of iris was excised. In healing, adhesion of the inner border of the pupil, as well as of the lens capsule to the cornea, took place. Gradually by contraction of the thick scar on the cheek which had united with suppuration, the lower lid became everted. This was after many weeks relieved by excising the whole length of the cicatrix, undermining the cheek on either side of it, and at its upper extremity making incisions right and left at a point about one quarter of an inch below the lid border, stretching up the lid Fig. 113. to open out the horizontal wounds and pulling them together from the sides. This raised the tarsal edge to place and brought the lid in apposition with the globe. More than once I have known the lid torn away from the inner canthus by a button-hook which a young child had thrust under its own lid. The tarsus is detached from the superior conjunctival sinus, and in replacing it, sutures must be first inserted on the inner surface through the tarsus and conjunctiva to secure its re- placement, and as a separate step the wound of the skin united. In a recent case no deformity need remain. Very recently a girl four years old inflicted the same injury upon her lower lid, tear- ing it off for two-thirds its length, and when brought to me ten days later, suppuration was established. It was necessary to freshen the edges of the wound, to extend it farther outward along the zygoma to compensate for the shortening due to its having flapped loosely for so long, and carry it well inward. Fine silk Fig. 114. 280 DISEASES OF THE EYE. sutures and the collodion cotton dressing held the parts immov- able for a week, and despite the tardiness of effective surgical help, union per primam was obtained with no deformity. Such accidents happen by bursting of soda-water bottles, by falling upon butchers' meat-hooks, by the thrust of a stick or of the horn of a cow, etc. Sometimes the levator palpebral is torn off, and the walls of the orbit may be fractured. Treatment must be adapted to the various exigencies which arise. If a canaliculus is torn, one may have to search for the remaining portion and open a way into the sac, which probing a few times with a lachrymal sound will keep patulous. If this be impracticable, the uninjured canaliculus will usually fulfil the physiological requirements. A blow or fall upon the brow often produces a wound of the skin which does not externally indicate its real severity. It may seem small and likely to heal by first intention, but suppuration and great swelling often occur because the skin is cut beneath by the sharp edge of the bone. Sutures are of little use and indeed may be harmful; warm poultices and antiseptic lotions are proper until the reaction subsides. Ecchymosis of the lids happens by blows and falls and some- times from straining in whooping cough or from senile degenera- tion of the vessels. If moderate in amount, stimulating lotions may in the beginning do good, such as alcohol and water, or as follows: 1> Tinct. arnicae, 3iv.; Liq. ammonii acetatis, 1 i.; Aquae, ad 1 viij. If there be a large clot, the practice of the prize ring is to tap it with a lancet and squeeze or suck the blood out. The proceeding is not strictly antiseptic, but evacuation of part of the clot is some- times good practice, care being taken to suture the wound or close it with collodion and cotton. After a few days no applications can be useful, save the artist's skill who " paints your eye while you wait." Coloboma of the lids is a congenital deformity which rarely occurs and usually affects the upper lid. It may be on the middle or nearer the inner end, as in a case which fell under my notice. There may be no other defect of structure. But much more exten- sive deformities are seen with arrest of development of the face. Treatment by paring the edges and uniting the opening by su- tures, as in wounds, is obvious. Epicanthus, sometimes called encanthus, is also a congenital malformation whose name is derived from crescentic folds of skin which run downward from the inner end of each brow, skirting the inner canthus and disappear over the lachrymal sac But in many cases several other conditions coincide with this and are of more serious moment. These are, deficient development or absence of the levator palpebrae superioris muscle, narrowness of the palpebral THE EYELIDS AND CONJUNCTIVA. 281 slits, with a tendency to slope upward at their outer extremities, great flattening of the ossa nasi. The deformity varies in degree, is apt to be hereditary, and to be associated with defects in the de- velopment of the eye, such as hypermetropia, or albinism, or nys- tagmus. I have seen three cases in one family. A striking case is figured by Von Ammon. The frontal portion of the occipito-fron- talis muscle is constantly called into play as in cases of paralytic ptosis, and the head has to be thrown backward to look at objects which lie even a little below the horizontal meridian. In some in- stances nothing can be done, or requires to be done, while in other cases the wrinkle at the inner canthus is unpleasantly conspicuous, and can be remedied to some degree by excising from the root of the nose an elliptic piece of skin, and undermining the adjacent folds very freely, so as to loosen them from their periosteal connections. The wound is closed by harelip or fine pin-sutures, and a vertical scar remains on the median line. Besides this, it is sometimes use- ful to perform the usual operation of canthoplasty at the outer angles. I have a photograph of a child who had a high degree of this deformity and aggravated converging squint. Nothing was ever done for her, because her drunken mother found the pitiful condition of the child a means of profitable mendicancy. Affections of the Muscles of the Lids. Spasm of the orbicularis occurs in two forms: the tonic or partial, and the clonic The first affects only a few fibres, is hardly perceptible, and is merely a trifling annoyance. It comes from strained accommodation, or slight conjunctival irritation; rest and general tonics are appropriate. The clonic form is sometimes called facial tic and is discussed in treatises on nervous diseases (see Gowers). It is paroxysmal and painful and the spasm often seizes upon other facial muscles. I have seen several examples of this affection. The face is thrown into ludicrous and painful grimaces, and the spasm is excited by very slight irritations. In the case of a car-driver who had two attacks of it under my observation, it once seemed to be produced by the severe cold of the winter wind. Only one side of the face was af- fected, and when the attack came, it would be thrown into extreme convulsions: the skin would become red, the mouth be drawn up, the lids lightly shut, and he would suffer severe pain. Such turns would happen many times a day, and they recurred during several weeks. He appeared to derive benefit from full doses of bromide of potassium. I have seen a clergyman whose whole face was thus contorted in interrupted paroxysms, and for whom reme- dies were of little value, but after several years I was happy to 282 DISEASES OF THE EYE. find that his affection had become almost imperceptible. Aconitine and gelsemium are remedies relied on, but materia medica is often useless. A less serious spasm, which is a kind of nictitation, may occur as an unconscious habit or trick. It may be confined entirely to the eyelids, and be a congenital and life-long peculiarity. A dis- tinguished sculptor of my acquaintance is thus affected, and has a little impediment of speech. A lady friend had it for seventy years, and her powers of speech were not impaired. Sometimes there will be a point of tenderness over the supra- or infra-orbital nerves, or on the temple, and perhaps at the back of the neck, or the cause of re Ilex irritation may be a defective tooth. Should such tender spots be found, they suggest indications of treatment, such as neurotomy, local anaesthesia, counter-irritation, hypodermic injection of mor- phia at the place of tenderness, etc. The disease is often cerebral, either cortical or nuclear. See Gowers, p. 660, Am. Ed. In many cases no treatment avails. It is important to bear in mind that sometimes the intensity of the symptoms can be greatly relieved by removing optical and muscular errors. While there may be some positive nerve or cen- tral lesion, removal of peripheral exciting causes may greatly abate the distressing symptoms. The analogy of such cases with as- thenopia and epilepsy is obvious. The following case is in point and more briefly is referred to on page 209. Dr. D. Yv., 47, first seen Dec. 29th, 1889. His father's grandmother became insane after the accidental death of her husband. His father has been twice confined in an insane asylum. The doctor himself resembles his mother, in whose family there is no insanity. No history of chorea or epilepsy on either side. Dr. W. has always been easily excited, quick to take offence, but is now much better able to control himself than in his younger days. Never had syphilis, rheumatism, or gout. Children strong and healthy. Dr. W. has suffered much from malaria, which manifests itself particularly in hemicrania and frontal headache, recurring every two weeks, but con- trolled by quinine. In the summer of 1881 he first noticed twitching of the right orbicularis muscle and consulted Dr. Weir Mitchell who suggested nerve section, but referred him to Dr. Thomson, who thought the trouble was reflex and cor- rected his refractive error under duboisia, viz., 0. D. + 1.00s. C + 1.00c. ax. 10° V. = l. O. S. + 1.75s. . . ax. 180° V. = 1. The correction was ordered for reading only. "While using duboisia he was free from the spasmodic action of the orbicularis and was somewhat re- lieved by the use of the glasses for a time. Later on the trouble increased, so that now, Dec, 1882, all the muscles of the right, side of the face twitch, the twitching being most marked in the orbicularis, wing of nose, and angle of the mouth in the order mentioned. There is tremor of the ocular muscles, producing nystagmus which prevents a view of the fundus of the right eye. There has been diplopia. After prolonged twitching there is numbness of the right side of the face. There is now tenderness over the supra-orbital, THE EYELIDS AND CONJUNCTIVA. 283 infra-orbital, malar, mental, and palatine twigs of the right fifth nerve and also over the styloid process, with hyperesthesia of the right side of the face. Without atropine, 0. D. + ^sc. ax. 10° V. = f£. O. S. + ^c. ax. 20° V. = U- ' The above glasses were ordered for distance with an additional + ^s. for reading. R Pot. iod. in increasing doses. Mar. 5th, 18^:5.—Has been much relieved by distance glasses. Less tender- ness over branches of supra- and infra-orbital nerves, although the spasms occur at night with considerable severity. Had tried pot. iod., hydriodic acid, and galvanism without effect. Has seen Dr. Janeway, who thinks the lesion may be thickening of a nerve sheath. Feb. 15th, 1888.—The glasses greatly relieve the spasm and he is unable to get along without them. The twitching is excessive if he leaves them off, and is confined to the right side of the face as before; it is greatly aggravated by any excitement. The eyes tire more quickly in reading than from any other cause and this provokes the spasm. He is often obliged to close the right eye in reading. The twitching is at times so excessive that he has great difficulty in getting to sleep. At times there is twitching of all the muscles of the right side of the face with slight numbness. Occasionally there is ptosis (right) and considerable rubbing and manipulation is required before he is able to open the right eye. Diplopia is an occasional symptom. Drugs have proved almost useless, although the bromide of ethyl and a 4£ solution of cocaine are, however, of temporary benefit. He has also been somewhat relieved by galvanism. Out of doors he rarely has any trouble. The nose is prominent, limiting the field of binocular vision to about 45°. Movement of O. D. outward is limited and irregular; movement of O.S. outward is also limited. Prisms with bases out render objects much more steady and distinct; without them he sees the gas jet as if through a fog. 18' abd. = 3° add. = 13° v. d. = 5* latent conv. 13" gl. abd. = 10°+ add. = 15° v. d. = 3° conv. Javal's ophthalmometer shows: O. D. 0.5 ± ax. 55°and 145°. O. S. 0.5 ± ax. 90° and 180°. 3 O. D. 4- 0.75c. ax. 10°CPrism H°, base out. O. S. + 0.50s. 3 + 0.75c ax. 20" C prism 1|, base out. June 18th, 1888.—Has found above glasses " wonderfully restful." Before wearing them could hardly get to sleep on account of the twitching, and then only by pinching up the skin over the right temple. Now has no trouble in getting to sleep unless very tired. Has much less twitching and less ptosis than formerly. Sept., 1890.—Still relies on glasses. Twitching grows worse. Paralysis of the Orbicularis Muscle, or Lagophthalmus— causes annoyance by exposure of the cornea. The eye is fretted by external irritation and overflows with tears which cannot be di- rected into the lachrymal puncta. Both the tensor tarsi and or- bicularis are flaccid and the lids fail to hug the globe. Chronic conjunctivitis, and even inflammation of the cornea are to be ex- 284 DISEASES OF THE EYE pected. The cause lies in lesion of the seventh or facial nerve. It is not uncommon for the orbicularis to escape when other muscles supplied by the inferior branches of the facial plexus are involved; but, if the orbicularis is paralyzed, all other muscles are also apt to suffer. The causes of facial paralysis are peripheral, or lie along the track of the nerve, or are in the brain. From the crookedness of its course, and the variety of tissues which it traverses, the nerve is greatly exposed to injury and it may be wholly or partially af- fected. One need only remember that diseases of the ear, and of the lymphatic glands, aud of the parotid, are all liable to do mis- chief to the facial nerve. As to the cases of cerebral disease, Eulen- burg says that facial paralysis, originating from lesions of the pons, involves the orbicularis; while, if it proceed from the cerebral ped- uncles, or from the central ganglia, or from progressive paralysis of cranial nerves, or from spinal cord affections, the orbicularis is likely to escape.x Peripheral paralysis of the seventh nerve usually includes the orbicularis. The cases of partial impairment are most common. I have seen two instances of total paralysis caused by wound in the space between the angle of the jaw and the mastoid process. In the case of a mason the wound was inflicted by falling on his own trowel. I have seen this patient sixteen years after the wounding and found partial recovery of function in the facial mus- cles. For seven years the outer half of the palpebral fissure was closed by tarsoraphy and then they were fully reopened. At this date (January, 1889) he has power to close the lids enough to pro- tect the cornea. Union of the ends of the nerve has doubtless oc- curred. Treatment will be governed by the supposed cause of the lesion. The remedies to be used will suggest themselves. If the cornea be much exposed, it may be necessary to wear a bandage, or to partly close the lid by a strip of plaster near the outer canthus. During sleep the lid will drop a little from its own weight, because the leva- tor is relaxed and the cornea turns up so as to be covered, even when paralysis is total. One of the aggravations of the trouble comes from the frequent wiping of the eye to get rid of the tears, and the lower lid is dragged down to an additional degree, and may pass into permanent ectropium. When this state arrives, relief will be afforded by paring the edges of the lids for ten to fifteen millimetres at the outer canthus, and uniting them by sutures to shorten the palpebral opening (tarsoraphy). The cilia are left untouched. The sutures should be left in situ from four to six days. I have lately seen a man for whom I did this operation seven years ago, and the relief it gave continued until within a few months. The continued paralysis and the drag of the lax tissues 1 See Gowers1 " Diseases of Nervous System," p. 657. THE EYELIDS AND CONJUNCTIVA. 285 finally brought on troublesome ectropium of the lower lid at the inner canthus, with a return of the former epiphora. I per- formed another operation of tarsoraphy at the inner canthus, in a different manner, as follows: I dissected up a parallelo- gram of skin above and below the canaliculi, for a space which reached from the commissure to three millimetres beyond the puncta. I turned the raw surfaces of the little flaps, raised from the respective lids, against each other and stitched through them. The puncta were thus turned inward and out of sight. The edges united, and the palpebral slit was left as a narrow oval through which the pupil could peep, and the annoyance of the epiphora was removed. Ptosis.—There is a so-called spurious ptosis or drooping of the up- per lid due to chronic trachoma and which remains after the disease is practically cured. The lid can be raised, but not to the full height. The levator is not paralyzed, but its action is hindered. Genuine ptosis indicates partial or complete paralysis of the levator palpe- bral superioris. It may concur with impairment of other muscles supplied by the third nerve, or be isolated. If complete, the upper lid covers nearly all the cornea, and is raised only by extreme con- traction of the occipito-frontalis, lifting the brow, and by trac- tion on the skin pulling, the lid up enough to enable the patient to peep under it, when he throws his head backward. The attitude of the head, when such patients attempt to use their eye, is highly characteristic. The causes of the disease are peripheral or central; the most frequent is syphilis. It may be well to remark that a little drooping of the lids may be congenital, and may be confined to one eye or affect both. The true action of the levator is con- spicuously suggested, when the only muscle able to act on the lid is the occipito-frontalis. The latter simply stretches the skin, and if lax, can exert but little effect, while the levator pulls from the cavity of the orbit and rolls the lid over the convexity of the globe, and at the same time causes a furrow in the skin. The treatment of ptosis consists, first, in combating the cause if this be ascertained; second, in stimulating the muscle by the fara- dic current of electricity; thirdly in operating. As to the first in- dication, we give iodide of potassium in small doses, gr. v. ter in die, for supposed rheumatic cases, and in larger doses with mercurials in syphilitic cases. This treatment should be held to, for four or six weeks. After the first week or two, the battery may be used for a few minutes, once daily, or as often as practicable. With one pole behind the ear, the other is placed on the lid, and the current should be only of moderate strength. After the lapse of three or four months without adequate im- provement we may employ an operation. The removal of a por- 286 DISEASES OF THE EYE. tion of skin and orbicularis fibres is the old mode. Pagenstecher, 1881, suggested the introduction of sutures beneath the skin to run up to the forehead above the brow, to be tied tightly, and by the resulting cicatrices after they have cut out, reef up the lid. Wecker has combined excision with sutures in a manner portrayed in the figures. A portion of skin and muscular fibres is removed from the upper half of the tarsus and its breadth will depend on the fulness of the lid. A strong thread is entered at a above the brow, pushed beneath it and the skin of the lid, keeping close to the tarso-orbital fascia, and coming out at the upper edge of the wound; it glides over the muscular fibres and then dips under the skin and muscle at the lower edge of the wound, emerging is carried transversely Fig. 115. Fig. 116. for a space of about five millimetres and then travels back on a reverse course up to b. Two such sutures are introduced. They are tied with a bow knot over a roll of plaster and tightened from time to time as they grow slack. The wound is thus pulled together and the due amount of effect is to be attended to. As the sutures cut through the tissues, cicatrices are formed which hold the lid up permanently. The proceeding is ingenious and superior to simple excision of a flap. I have done it with benefit in a case of ophthalmoplegia exterior bilateralis, where not only ptosis but paralysis of all the extrinsic muscles existed. The case was con- genital and the lesion nuclear. If other branches of the third nerve are paralyzed, it may be inexpedient to cure the ptosis because the patient will be subjected to the distressing annoy- ance of double vision. The drooping of the lid succeeding trachoma may be relieved by THE EYELIDS AND CONJUNCTIVA. 28? sutures employed in a manner similar to Hotz's operation for en- tropium (Gruening). An incision is made just below the upper edge of the tarsus and parallel to it. Some orbicularis fibres may be ex- cised. With a sharply curved needle the thread is pushed along the surface and upper edge of the tarsus through the conjunctiva, until it loops up the cul-de-sac and returns upon itself beneath the skin to come out at the upper part of the wound. It never traverses the skin. Three sutures may be used. They are tied tightly and allowed to remain two to five days, according to the degree of re- action. The skin wound is closed as usual. By the same proceed- ing, if the needles are carried up to the edge of the orbit and en- gage the periosteum a much greater effect will ensue and superior to that secured by Wecker's operation just described. Drooping of the lid from redundancy of skin is easily cured by removing a suitable flap. The proposal to advance the tendon of the levator has not met with general adoption; it is not effective enough to be useful. An attempt has been made to enable a patient to open the eye by using a cord of india-rubber (Von Bibber), one end of which was fastened by plaster to the lid, and the other to the forehead. With the same object a spring clamp to pinch up a fold of skin has been devised, to be worn habitually. Neither the clamp nor the rubber band commend themselves in point of elegance and not much in utility. A moderate degree of ptosis is one of the symp- toms of disease of the sympathetic in the neck which was first pointed out by Horner. It will be referred to later. See page 469. Two cases of lipomata of both eyelids causing ptosis are reported by Schell. Burns of the Eye. Superficial burns of the tegumentary surface of the lids need not detain us, but those of the conjunctival surface are important be- cause they often lead to adhesions of the lids to the globe or to each other. Caustic materials or melted metal are the usual causes of the accident: for instance, fresh mortar, lime, nitric or other acids, ammonia, melted lead or iron; and red pepper may be mentioned, which, while not destructive, is extremely irritating. When lime gets into the eye, it must be washed copiously with water, but the only effective means of removal is by forceps, or a spud or curette; wiping out the coarser masses with a bit of rag will serve, but the little pieces which remain, eat their way into the tissue and become incorporated with it. At the inner canthus, and in the cul-de-sac, it will be lodged, and must be dug out patiently and thoroughly. Often ether must be administered. After com- plete removal, syringe away all particles with warm water. The relief for pain is cocaine and cold water. Of course an anodyne may be given. The danger is of adhesion of the lids to the globe, 2S8 DISEASES OF THE EYE. and of deep opacity of the cornea. The lids must be pulled away from the eye and adhesions torn several times daily, and in mild cases good will follow. Nothing can prevent the formation of attachments in case the burn is deep, as the resulting ulcer slowly granulates and contracts. Shields of lead, and dressing with lint and sweet oil, and pulling the lid away, are then unavailing, but a shell of glass resembling that used as an artificial eye, transparent and convex enough to leave the cornea untouched has lately been tried with some success. I should advise a mixture of iodoform and vaseline on the cornea, say 3 i. ad 3 L, in bad cases where its infil- tration threatens. Fulminate of silver or mercury, which are used in percussion caps and in boys' torpedoes, besides their terrific explosive power, have a peculiar destructiveness in the kind of burn produced. The conjunctiva becomes covered by a deep gray thick exudation, which can be pulled off in sheets, leaving a raw, bleeding surface, and is speedily reproduced. It resembles the worst forms of diphtheritic exudation and is attended by severe inflammation. The cornea may share in the process, and if it do not, is most liable to ulcera- tion. The destruction of the conjunctiva leads to adhesions of the lids to the globe. I have seen two accidents of this nature, and their results were deplorable. Burns by melted metal are, often less severe than those due to lime, because when the metal cools it is taken out as a cup, and there is no continuously destructive chemical action. Nitric, sul- phuric, and acetic acids, can do great mischief. They are to be washed out with cold water freely applied, and the case treated for subsequent reaction. Ammonia causes a more superficial es- char, and is exquisitely painful. Besides cocaine we may use castor oil, vaseline, ice, etc. For red pepper, however dastardly its inten- tional use, it may be said that it does not cauterize. The ulcers caused by burns are damaging to sight in the ratio in which the cornea has been involved. But a better result can generally be expected than the first look of the case suggests. Several weeks or months will be needed for recovery. Symblepharon. — When the ultimate contraction has been reached, we have adhesion of the lid to the globe, called symble- pharon, and the question of repair is to be considered. The diffi- culties are in proportion to the extent of adhesion. For columnar bands, good results are possible; for total attachment of the whole lid-surface, the difficulties of an operation are great. No good at all is to be had by simply dissecting the tarsus and globe asunder— the lid is sure to go back to its old site. Naturally, the lower lid is the most frequent sufferer. Frequent traction on the cicatrix will in time stretch it to a greater or less degree. The cure is attained THE EYELIDS AND CONJUNCTIVA. 289 by means which shall not only separate the lid from the globe, but prevent readaptation. For columnar attachments, the old pro- posal of inserting a lead wire through the mass at the fornix is of value. It has to be worn until a permanent hole is formed, which shall be lined by a kind of epithelium; then the adhesions may be :ut, and the parts can be kept from growing together. But this operation is superseded by one of Arlt's (Fig. 118). He dissects down the frenum, beginning on the globe, until he lifts it up to the fornix. Through its free end a thread armed with two needles is passed, and these are pushed through the cul-de-sac to the surface of the skin, and the thread tied over a roll of plaster or bit of wood; by this device the outer surface of the column is laid against the globe. The raw surface is now covered over by bringing down flaps of conjunctiva from either side. A glass shell may be worn over the Fig. 117. Fig. 118. globe which will aid in preventing contraction. If the new tissue overlap the cornea, it may be left in situ and the dissection made where the edge of the cornea should be, as in Fig 117. For more extensive degrees of symblepharon, another operation is available. The adhesions are dissected down to the fornix, then the vacancy on the globe is to be filled, while the lid is left to itself. Instead of sliding flaps of conjunctiva, as may be done in mild cases, a kind of sling is made in this way: from near one side of the vacancy a curved incision in the conjunctiva is carried around, just outside the cornea, to the opposite side of the vacancy. Then another incision, concentric to and outside this, is carried around, but its extremities must not come nearer to the vacancy than five to seven millimetres. It may even go up to the fornix, and with the first incision it incloses a band which may be from five to eight millimetres wide. Care is taken to make the ends of the band the widest part, by turning the extremities of the upper wound upward. The band is then loosened, except at its ends, and slipped down over the cornea to take its place in the 19 290 DISEASES OF THE EYE. gap made by removal of the adherent cicatrix. It is convenient to put threads into the edge next the cornea before making the outer incision: they serve to hold and draw down the flap, and are used to fasten it in place. They may be carried entirely through the lid and tied on the skin. Some readjustment of intervening and adjacent conjunctiva is required, while the flap is carefully fastened by fine sutures in its bed. The spot from which it has been taken is left to itself. That in time, by granulation, be- comes covered by a tissue which perfectly resembles normal con- junctiva. The result of the operation is most fortunate, and I have done it several times with great satisfaction. Operations by put- ting in separate flaps from either side, twisting them down, and uniting them by suture at their free ends, have been done by Knapp, Teale, and others. Mr. Teale, who first suggested conjunctival flaps, applied one to the inner surface of the lid after it had been dissected off and applied another flap to the eyeball, so that the epithelial surfaces should be in contact. For cases which may be too bad for this proceeding, grafting of bits of conjunctiva from the rabbit is available, and results in benefit. In most of these cases, the loosen- ing of the adherent scar is demanded, for relief of pain and discom- fort, without regard to sight. In many others additional opera- tions, chiefly iridectomy, may be needed to gain better vision. The transplantation of portions of conjunctiva from the rabbit is serviceable in extreme cases, and aided by wearing a glass shell will often, as my own experience has shown, give success. It is also the only available method in attempting to make a conjunc- tival cavity to permit the insertion of an artificial eye. I have lately seen a boy on whom I operated eleven years ago, when he was twelve years old. The eye was lost and reduced to a stump, and extensive symblepharon existed. It was impossible to wear an artificial eye. In March the adhesions were dissected away and as large a strip as could be taken from the rabbit's eye, inserted. Soon after a very small shell was worn and the size gradually in- creased. In May following, the operation was repeated, and larger shells employed. In four months longer, a suitable artificial eye could be worn, and now, 1889, he continues to wear it and the con- junctival cavity is capacious and perfectly healthy. Pieces of mu- cous membrane can be taken from the lower lip and transported. The skin of the lower lid or of the temple may also be employed, as has been done by Harlan and Snellen (see Oph. Review, Dec, 1890). I have lately employed skin grafts of large size (Thiersch's method) with good result for preparing a cavity in which to wear a glass eye. Similar grafts might be used to line the raw surface of a lid when dissected from the globe, stretched in place by sut- ures, dressed with aristol, and the whole covered with bichloride gauze, 1 to 1,000. THE EYELIDS AND CONJUNCTIVA. 291 Ankyloblepharon is the adhesion together of the tarsal bor- ders, and is a result of burns and of wounds. It is easily remedied if there be any free spot or hole from which to start in separating the lids. If not, the attempt is useless. One must establish a per- manent hole by wearing a metal ring or other method. But such a necessity has never occurred to me. Sometimes the lids are both completely attached to the globe, and also adhere to each other at their margins. For such cases no interference is proper. Such a case is exhibited in the illustration, where complete occlusion was caused by a piece of red-hot iron, both searing and sealing up the eyeball. The same result is sometimes procured when for cancer- ous disease both the globe and part of the lids must be removed. Under such conditions all of the conjunctiva, both palpebral and bulbar, must be dissected off and the edges of the lids pared. Such an operation was necessary in the case of epithelial disease of the lids which ultimately passed to the eyeball figured on Colored Plate No. VI. OHAPTEE III. DISEASES OF THE LACHRYMAL APPARATUS. Anatomy.—We have to do with the secretory and with the ex- cretory parts of the apparatus. The former, which supplies the tears, consists of a series of small follicles situated in the superior conjunctival cul-de-sac, and the lachrymal gland, while the conjunc- tiva itself secretes moisture, which may be counted part of the lachrymal fluid. The lachrymal gland is lodged in a fossa at the upper and outer angle of the orbit, and may be felt by the finger indistinctly under its overhanging rim. It is an acinous gland like the parotid, subdivided into a smaller and a larger lobule, which are separated by a septum of fascia. The smaller is sometimes called an acces- sory gland. There are numerous isolated acini lying near the prin- cipal masses. The size of the chief gland is variable, but may be stated at twenty millimetres in length, eleven to twelve millimetres from before backward (breadth), and five millimetres in thickness. It is concavo-convex, and lies against the periosteum. Numerous ducts, whose orifices are from ten to twelve in number, give exit to the secretion at the temporal side of the superior fornix. The tears contain 1.25 per cent of sodium chloride and 0.5 per cent of albumen. The excretory apparatus begins as minute openings (the puncta), about six millimetres from the inner angle of the lids, which lead into small canals (canaliculi), and they unite to empty by a com- mon orifice into the side of the lachrymal sac. The sac rises a little above the place of entrance of the canaliculi, and is continuous below with the lachrymo-nasal duct, which empties into the inferior nasal fossa, behind the tip of the inferior turbinated bone. The total length of the sac and duct is about one inch (twenty-five mil- limetres). Its section is ovoidal, with the long axis from before and outward, backward and inward. Its calibre varies greatly, and its shape may also vary. In the same skull, from which the soft parts have been cleared, I have seen the duct on one side to be round, and not more than three millimetres in diameter, and on the other to be oval in section, with its major axis six millimetres long. The membrane lining the duct and sac is like that of the nostrils, DISEASES OF THE LACHRYMAL APPARATUS. 293 being both a periosteal and a mucous membrane. It is highly vas- cular, thick, and covered by cylindric epithelium, lying on several layers of spheroidal cells. The cylindric cells are by some declared to be ciliated. Next the bone the membrane is spongy and erec- tile. It is thrown into folds at two or three points, viz., at the junction of the sac and duct, which corresponds with the beginning of the bony portion of the tube in the ascending process of the superior maxillary bone, and also at the lowermost part, where it communicates with the nostril. There is also, sometimes, a less distinct fold at its middle. The lining membrane of the canaliculi is thin and pale, and the puncta are a little whiter than the neigh- boring membrane. They point toward and rest in contact with the globe. Muscular fibres surround these openings like sphincters, and they are held in apposition with the eye by the action of the orbicularis and tensor tarsi muscles. The latter lies behind the lachrymal sac, and the tendon of the former crosses in front of it and is sometimes called the tendo oculi. It is brought into relief by pulling upon the lids at the outer can- thus. The orbicularis has additional insertion into the lachrymal bone, by bundle's of fibres which go to it directly. The tears are forced into the excretory passages by the action of the muscles just mentioned, aided by a kind of suction caused by the muscular fibres of the puncta and canaliculi (Klein). Unless the puncta are kept in tonic contact- with the eye, the tears cannot enter. The quantity of fluid is usually so small that evaporation and secretion balance, and nothing passes down to the nose. With any irritation of the eye, a larger flux occurs, and frequently the capacity of the tubes is overtaxed and tears brim over the lids (epiphora). Usually the follicles in the superior fornix and the conjunctiva furnish all the needed moisture, but on unusual demand the lachrymal gland comes into play. Diseases of the Lachrymal Gland. Acute inflammation, dacryo-adenitis, occurs in rare instances. I have in one case seen both glands inflamed at the same time. The symptoms are, swelling, by which the gland is pushed down out of its fossa and can be recognized on turning up tlie lid; there is oedema of the lid, tenderness of the gland and of the adjacent bony edge, together with dull pain. The amount of swelling can be great, and it is sometimes difficult to exclude periostitis or abscess of the lid. There ma}- be suppuration in the surrounding connective tissue, while often the inflammation resolves without suppuration. The treatment consists in warm fomentations and incision into acute inflammatory swelling. Constitutional treatment is not often 294 DISEASES OF THE EYE. needed, although the possibility of a syphilitic cause is not to be ignored. The gland may be the seat of neoplasms, such as sarcoma and other tumors, and of cystoid degeneration, and it is liable to chronic hypertrophy; but these conditions need no special consideration. Its extirpation to cure epiphora was practised by Mr. Lawrence, but is not now approved. Dislocation of the lachrymal gland came under my notice in a young girl and seemed to be due to slow relaxation of the inclos- ing capsule. The gland presented itself beneath the ocular con- junctiva over the insertion of the rectus externus muscle and was affected by slight degree of inflammation which was not, how- ever, the cause of the displacement. The opposite eye was phthisi- cal and there too the degenerated and atrophied lachrymal gland had descended below its proper place. Diseases of the Excretory Apparatus. We have eversion and stoppage of the puncta, occlusion of the canaliculi, catarrh of the sac, and obstruction of the duct. We also have acute dacryocystitis, chronic distention of the sac, and fistula lachrymalis. Sometimes there are two canaliculi in each lid. Eversion of the puncta is the consequence of chronic blepharitis marginalis or of chronic conjunctivitis, or it follows from paralysis of the orbicularis muscle in lesions of the facial nerve, and neces- sarily accompanies ectropium. In the first class of cases the orifice is apt to be made smaller; in the paralytic cases the punctum may be uncommonly prominent as a papilla, and while the lower one sags down, the upper also fails to lie upon the globe. The canaliculi are sometimes the seat of stricture, and in a few cases chalky concretions have been found in them. Leptothrix, one of the microscopic algae, has been found in them. Dacryocystitis or catarrh of the sac and duct is a lesion not often presented to us at an early stage, because people are apt to avoid the surgeon until the disease has lasted so long that simple catarrh has become complicated with obstruction. There is prac- tically no real distinction to be made between these conditions. In dacryocystitis we have swelling of the mucous membrane, h}Tper- trophy of its epithelium, and papillary growth—sometimes a state precisely like granular conjunctivitis, and with this a muco-purulent, glairy, somewhat tenacious secretion, which fills the cavity and is there retained. The calibre of the nasal portion of the passage speedily becomes choked, and the morbid secretion cannot find out- let; hence, the sac-wall undergoes distention. The three factors of thickening of the mucous membrane, excess of secretion, and dis- DISEASES OF THE LACHRYMAL APPARATUS. 295 tent ion of the sac, gradually conspire to bring about a more or less aggravated condition, in which the lachrymal tumor becomes larger and the stricture smaller. The skin, after a long period, becomes thin, and may even get to be translucent. It may in very old cases happen, that the lachrymal bone becomes diseased. The constant and annoying effect of this state of things, at almost any period of its existence, whether early or late, is to cause an undue quantity of tears to be formed; they overflow the lid or stand ready to drip over. On exposure to wind or to cold air, the eye waters, uncom- fortably, and the fluid sweeping over the cornea makes vision misty, and continuous use of the eye is sometimes, and more espe- cially at night, greatly embarrassed. The tears which thus flow too liberally are called forth, it is true, by a hypersecretion of the lachrymal gland; but they are likewise mingled with the products of the irritated conjunctiva and its glands. The universal concom- itant of dacryocystitis is palpebral conjunctivitis, sometimes severe, and not infrequently blepharitis marginalis coexists. The caruncle and semilunar fold are swollen and injected, and aid in hindering the entrance of fluid into the puncta. The patient is constantly using his handkerchief, and thus materially aggravates his troubles. But he may learn, and this should be taught by the physician, to keep the sac empty by squeezing its contents into the nose, if the passage be permeable, or the secretion gushes out of the puncta upon the eye. Wherever it goes, keeping the sac empty affords some relief. But when the disease has lasted long, the secretion acquires irritating qualities, especially if it be permitted to stay long unex- pelled from the sac. Then its contact with the eye sets up decided conjunctivitis, and the fluid may even have an offensive odor. The fluid then is sticky and unpleasant; especially is it mischievous if the eye is submitted to an operation. The pus has an infectious quality, and is extremely apt to cause suppuration in a corneal Wound. The reason of this pernicious quality is the populous- ness of micro-organisms of many varieties in the secretion. With the exception of the gonococcus none are known to be more hurtful to the tissues of the eye. It follows that cases of cataract, or cases which require iridectomy, should be first relieved from any lachry- mal trouble. The disease is of slow progress, and often for a long time causes little annoyance. Even after a tumor appears at the inner can- thus, the swollen sac may not cause great discomfort. But, if it be impracticable to empty it by pressure, the stricture is close and the condition will be both obstinate and troublesome. A most unpleasant complication in the progress of the disease is the occurrence of acute phlegmonous inflammation and abscess. This is severely painful, and may cause extreme swelling of the 296 DISEASES OF THE EYE. lids and neighboring parts. The tumor will be red, shiny, and tense. If not large, it will be very tender to the touch, and the conjunctiva will be hyperaemic. It is quite characteristic to find the swelling in the /old of the lower lid and sometimes there is so much infiltration of the skin as to suggest erysipelas. If the pro- cess be left to itself, the matter finally escapes by ulceration, and in this case a fistula lachrymalis is quite liable to ensue. The opening will be below the tendon of the orbicular, and may be large or small. (See Fig. 119.) In cases which have been long neglected, the subjacent bone may become carious, and a passage may even take place into the Fig. 119. superior nasal fossa, or into the cells of the ethmoid. In general, the disease will either remain stationary or grow worse__it does not get well. It may be tolerated for years with slight discomfort, or it may prove unpleasantly exasperating. (I have seen one case of congenital lachrymal fistula affecting both eyes. It was re- ported by Dr. Agnew *.) Before entering upon the consideration of treatment, a few words may be given to a condition which causes epiphora and is apparently not associated with the morbid lesions above described. I have seen a few patients who were annoyed by an accumula- tion of tears, in whom I could find no swelling of the sac nor ten- derness over it, nor could I elicit any discharge. At the inner can- 'Trans. Am. Oph. Soc., 1874, p. 209. DISEASES OF THE LACHRYMAL APPARATUS. 297 thus there was swelling of the semilunar fold, and turgescence of the caruncle; the puncta were prominent, but not everted nor choked, neither was there obstruction of the canaliculi. The cause of the epiphora seemed to be the swollen state of the caruncle and of adjacent parts; this irritation excited hypersecretion of tears, while the prominence at the canthus served to obstruct entrance of the fluid into the puncta. This rare condition has been noted by Graefe, and I have seen it a few times. Diagnosis.—We have epiphora and a swelling over the lachry- mal sac The tumor will be effaced by pressure of the finger, and its contents will either flow over the eye through the puncta, or else Fig. 120. pass through the nose. If by pressure the tumor do not wholly subside, the sac-wall may be very thick, or the stricture be very tight. If very large and the walls thin, its bluish color may sug- gest a cyst; but the history of epiphora will settle the doubt. The caruncle is red and apt to be swollen, and the puncta also to be swollen and red, and of unusual size. In some very quiescent cases no tumor appears, but pressure will force fluid into the nose. These varieties depend on the duration of the malady, and on the amount of secretion and the degree of obstruction. We sometimes meet cystic or solid tumors of the skin overlying the sac, they will be recognized by the possibility of grasping them with the thumb and finger, or by their mobility and the absence of other signs. A mucocele or chronic abscess of the ethmoid cells sometimes points in the lachrymal region. Its position will be higher than the sac, 298 DISEASES OF THE EYE. and above the tendon of the orbicularis instead of beneath or be- hind it (see Fig. 120). Causes.—The prevalent cause is catarrh of the nasal mucous membrane. This cannot, however, always be discovered. We have frequently the scrofulous diathesis and also frequently constitu- tional syphilis. A local periostitis at the nasal outlet of the canal may be the starting-point. In most cases the disease is essentially a periostitis and, remembering this characteristic, its special and pertinacious behavior will not be surprising. Prognosis, as has been intimated, is that recovery will be slow, requiring months. Six weeks would be a satisfactory period—six months not infrequent. Sometimes relief can only be partial, yet it can be absolute and complete. The pathological conditions are so varied that the expectation of cure must be determined by the fea- tures of each case. Treatment.—We have the palliative and curative. A consider- able number of persons are not greatly disturbed by their lachry- mal trouble; another portion are too timid to submit to surgical proceedings, and others are unwilling to spare the time which effec- tual treatment demands. For these patients, only palliative pro- eedings can be used, and they are as follows: To keep the sac empty by pressing on it with the tip of the finger from above, down, and backward, so as to force the fluid, if possible, into the nose, with firm slow pressure. A certain knack is often acquired by the patient which the physician cannot imitate. If the fluid must be disgorged on the eye, the handkerchief must be in hand to absorb the fluid at once without needless rubbing of the lids, and at all times the eye should be gently pressed, and not wiped. The sac must never be allowed to approach distention. The use of astringent drops or of a lotion upon the lids, or occa- sional astringent applications to the palpebral conjunctiva, e. g., Argent, nitrat., gr. ij.-v. ad | i., as this surface may become more congested, will do good service. Moreover, the state of the nasal cavity must be inspected, and duly dealt with. Washing out the nostrils with warm salt water by a syringe, the application of depurating and astringent fluids by an atomizing apparatus, or by the blowing of powders into the nostrils, in the manner called for in the treatment of nasal catarrh, will be well worth doing Dobell's formula is widely employed. ty Sodae biboratis,.......3 iv, Glycerini,........31. Sodae bicarbonatis,......3 ss. Acid, carbolici,.......3 ss. Aquas,......... | yi. M. DISEASES OF THE LACHRYMAL APPARATUS. 299 For powders, among many which may be chosen are the follow- ing: IJ Bismuthi trisnitrat., Gum. acacias, . . . . . . aa 3 i. Pulv. cubebae,.......gr. x. M. 1} Acid, boracic pulv.,......q.s. Under such management, some persons get along fairly well and are satisfied. Many do nothing more than keep the sac empty, and expect when they get a coryza to have more trouble—and so they do. The curative treatment involves a careful discrimination of the state of the sac and duct, and the suitable adaptation of means. If the lachrymal tumor is easily emptied into the nose—and this implies that the case is recent—external applications may suffice. In children of a strumous quality it may be only possible to use probes by giving chloroform, and often the cleansing of the nostrils by a camel's-hair pencil, and the use of cod-liver oil, iodide of iron, etc., will bring about recovery. Carefully wipe out the nostrils with cotton on a holder, and apply vaseline twice daily, and a solution of nitrate of silver, gr. x. ad § i., twice or thrice weekly, or the powdered boracic acid once daily. But the common run of cases call for treatment of stricture of the nasal duct. Becker uses conical probes with which he stretches the punctum and canaliculus and reaches the duct. The proceed- ing is painful and permits the introduction of probes of only mod- erate size, which are inadequate in many instances. The first step is to slit the canaliculus, which Mr. Bowman taught to be the best mode of approaching the sac. My preference is for the lower one. I also choose a beaked knife, with a blade wider than is generally used (see Fig. 121), attached to a long and stiff, but malleable shank. Sometimes a narrow blade is useful (Agnew). (See Fig. 122.) For a case of no long duration it may be needful to do no more than slit the canaliculus. The surgeon, if operating on the right eye, will stand behind the patient, hold- ing the head against his own body, use the left hand to draw the lower lid out and keep it tight, and insert the beak of the knife perpendicularly into the lower punctum. Sometimes this is partially occluded. The point of a pin or a Bowman's direc- tor (see Fig. 123) will usually open it for the tip of the instru- ment. When well engaged, bring the hand to the horizontal position, and push the blade with cutting edge inclined inward and upward into the sac until the tip is felt to strike the lach- rymal bone; keeping the point firmly against the bone, raise the 300 DISEASES OF THE EYE. handle up, and also lift up the blade so as to incise as freely as possible the conjunctival wall of the sac. Many surgeons stop at this point and let the patient apply cold water, and on the next day attempt to introduce a probe. In the greater number of cases I do Fig. 121. Fig. 122. Fig. 123. Fig. 124. Fig. 125. S.TIEMANN &C0 Fig. 126. Fig. 12?. not follow this mode of proceeding, but at the first operation carry the knife down into the nasal duct and divide the stricture. I make two or three incisions upon different sides of the duct, to gain the greatest enlargement. Blood issuing from the nostrils is proof that the passage has been opened. When the stricture is divided DISEASES OF THE LACHRYMAL APPARATUS. 301 as Stilling recommended, a large instrument should be inserted, viz., the larger end of Weber's conical probe (see Fig. 124), and afterward the probes of large sizes. Cases must be dealt with according to the calibre which is normal to each, and the fullest possible expansion obtained. The first operation may perhaps be done under an anaesthetic, and often two or three days will elapse before another introduction of a probe. Meanwhile the canaliculus must not be allowed to close. The introduction of probes is always painful and cocaine does not serve any useful purpose, no matter in what method employed. Usually the proceeding is less painful as the cure progresses. The probe may be used three times weekly, and be left in place from ten to thirty minutes. Progress can, in some cases, be made rapidly; others will permit only a gradual increase. The amount of reaction after probing will regulate the frequency of introduction and the rate of enlargement. In passing the probe carry it hori- zontally into the sac, and when its point impinges on the bony wall, bring it to a perpendicular and attempt to follow the axis of the duct. The direction is downward, outward, and backward, toward the wing of the nostril. The aim must be to get behind the edge of the opening into the superior maxilla, and until this is gained the probe must be handled with delicacy, and in the exercise of a nice sense of touch. Caution at this point is indispensable, and a moderate degree of it will avoid making a false passage. After this opening is gained, the probe may be firmly sent down until it reaches the nasal fossa. It should be left in place for ten min- utes, and then withdrawn. This exploration will indicate what kind of stricture we have in hand, and what instrument will best dilate it. I have, during many years, made use of Theobald's probes (Fig. 125), and find them exceedingly satisfactory. They go up to large sizes, No. 16 being the maximum. Dr. T. has advocated the use of large probes in a paper in Arch, of Ophth.,vi., and in Trans. Am. Oph. Soc, 1879, and was not aware that Dr. E. Williams, of Cincinnati, myself, and others had, for many years, sought to secure the full- est dilation which the anatomical and pathological conditions make possible. Dr. H. W. Williams, of Boston, has introduced probes with bulbous tips and elastic necks (Fig. 126) which, while stiff enough to handle easily, find their way around projecting obstacles or through sinuous passages better than straight instruments. I have often had occasion to be pleased with their qualities. But my ultimate resort is to a large instrument, smooth, with conical point, which must press its way through the inflammatory deposit—not with violence, but with some force; and this is to be left in situ from ten to thirty minutes, but not long if its pressure be extremely 302 DISEASES OF THE EYE. painful. Making haste slowly is the password to success with these cases, but I am convinced that the gate must be opened widely and made to stay open, to get full relief. Dr. Theobald's probes are of the following sizes: beginning with the diameter of one quarter of a millimetre, advancing by increase in diameter of one-quarter of a millimetre from No. 1 to 16, the last being four millimetres in diameter. I have found them so well contrived that I have adopted them almost to the exclusion of all others. The largest sizes are now made of aluminum with the advantage of lightness and greater smoothness. As the result of probing, abatement of the catarrhal secretion is soon manifest. In most case, nothing more than probing and treatment of palpebral conjunctivitis is needful. In a certain num- ber, secretion is copious, and does not measurably diminish. The syringe must then be employed with salt and water 2$ or with a weak solution of argent, nitratis, gr. v. ad \ i., or gr. x. ad § i. Perforated probes have been devised for this object, but a small, hard-rubber dental syringe can be readily adapted to the purpose by bending its nozzle in hot water to an obtuse angle. After the probe has been withdrawn, the syringe may be used. It will not require protracted employment. In cases where persons cannot spend the weeks or months with the surgeon which treatment requires, the plan may be adopted of putting in a leaden wire, about size No. 6 or 4 Bowman, which shall lie in the duct with its upper end properly bent downward and in- ward at the inner canthus. This style may be worn as in old times Scarpa's nail was worn, for two months, more or less, and it will then be found to have brought about absorption of the stricture. It excites considerable secretion, is not agreeable to wear, but an- swers fairly well. Granulations are liable to spring up at the en- trance into the sac, and when the style is taken out, the opening soon contracts and is difficult to find. I have another suggestion to make in this matter. Some cases permit dilatation of the stricture with reasonable rapidity and to a satisfactory degree, but the annoying epiphora does not stop, and the patient does not find the pain of the treatment compensated by good results. It must be remembered that there may be an- other stricture at the bottom of the duct where it enters the nose. Here I have many times found a nodular projection from the side of the canal, or a decided narrowing of its calibre. To overcome this stricture the common probe is futile. I have had a form made which is a repetition of a very old instrument, with a bulbous tip and of unusual length (see Fig. 127). It is carried down to the lower end of the canal in the ordinary way, and then, to get it into the nose the flat handle must be rotated toward the temple so as to turn the DISEASES OF THE LACHRYMAL APPARATUS. 303 point backward, and then push it onward. It will go down almost an inch farther, and it may so far penetrate the nostril as to touch the place of junction of the hard and soft palate. Some obstinate cases of epiphora have been cured by ascertaining the presence of this hidden stricture, and resorting to the instrument thus de- scribed. In cases where the obstruction at the bottom is osteoid, I have used a narrow gouge with a cutting end, and have bored a way into the nose (see Fig. 128). Afterward steady probing is needed to prevent the return of the obstruction. I have found Theobald's probes frequently able to cope with the cases just cited, because of their well-fashioned tips and greater length. But they deserve special notice, and the probe I have de- vised will sometimes be necessary. There remains another class of cases in which the passage can- not be restored to its normal state: either because of excessive Fro. 128. thickening of the lachrymal sac, or the duct is almost occluded by osteoid growth, and is practically impermeable, or there may be caries. The older writers proposed opening into the nasal fossa by perforating the lachrymal bone. The modern treatment is the ob- literation of the lachrymal sac and duct. This is done by dissect- ing out the hypertrophied sac, or by destroying it either by the actual or potential cautery. Excision of the sac may be combined with the cautery. After dissecting out with scissors as much of the sac as can be removed, the Paquelin cautery is thrust into the duct. Usually, fuming nitric acid is the agent employed. The sac is freely exposed by an incision in the skin, and when the bleeding stops, a bit of wood—the untipped end of a match—with some fibres of cotton on it, is charged with it and freely applied to the mucous surface. Care must be taken to protect the eye, and the edges of the wound must be held asunder by sharp hooks. This operation has been done by Dr. Agnew through an incision upon the mucous side of the sac, with simultaneous division of the canal- iculi, and he reports good results. I have not followed his method; and although, as commonly performed, a scar is left upon the skin, I have not found it a. conspicuous thing or a deformity. Still an- other mode of destroying the sac is by putting into it pieces of nitrate of silver. They cause prolonged pain, and are less effectual 304 DISEASES OF THE EYE. than the Paquelin or the nitric acid. After cauterization the sac is stuffed with lint, and cold water dressings applied. It will take two or three weeks for the wound to close by granulation. When the cavity is obliterated, the success which follows in reliev- ing the epiphora, depends on the fact that there is no longer an irritation in the sac to stimulate a superabundant flow. The ob- struction of the excretory passage causes no inconvenience, except when some special occasion for weeping arises, such as keen winds or mental emotion. In fact, however, it is not easy to perfectly obliterate the sac and duct, and hence this treatment does not give uniform results; but it is a great amelioration of the previous con- dition. In very young children a probe may be passed by the help of chloroform. I have seen lachrymal abscess with stricture, on both sides, in a child six months old, and treated it successfully by the usual method. I have sometimes instructed a patient to use the probe for himself, when he had reached the proper size, and simply needed to maintain the enlargement. Added to the above suggestions for local treatment, the possi- bility of syphilitic infection must be borne in mind and the suitable medical treatment adopted. In late tertiary forms I have found this condition. The iodide of potassium and corrosive sublimate will do the same service as in any case of specific periosteal inflam- mation. In all cases where nasal catarrh shows decided symptoms, this must receive attention. Phlegmonous Inflammation of the Lachrymal Sac. This takes place as an incident during the progress of a chronic dacryocystitis. The attack is always painful, may be ushered in by a chill, and varies greatly in severity. Swelling, tenderness, and hardening of the sac are always present, while sometimes the lids become puffy, especially the lower lid along the furrow which lies below it and in a few cases the oedema of surrounding parts has simulated severe orbital cellulitis. Even though the swelling be small and circumscribed, the patient commonly suffers much pain, and the reason is the same as in the case of any subperiosteal in- flammation, viz., the effusions are compressed by dense membranes and the nerves are numerous. Treatment.—It is rarely of any use to do anything else than to make an incision into the sac If the case be seen early, this may be done by way of the canaliculus and slitting freely the sides of the sac, thus preparing for the probe at a future period, when treatment of the original stricture shall be in order. But if much swelling have taken place, the knife should be put perpendicularly upon the skin over the middle of the sac and thrust through it to DISEASES OF THE LACHRYMAL APPARATUS. 305 the bone, and then with one sweep carry the incision down for half an inch, more or less, according to the extent of the tumor. The best surgery is an early and a free incision. By doing this the oc- currence of fistula is almost certain to be avoided, while it is very likely to be the disagreeable consequence of permitting the abscess to " break of itself." After opening the abscess, warm water dress- ings and poultices will be applied until the attack subsides. The cut will be kept open by a bit of lint. It is not denied that sometimes, when phlegmonous inflamma- tion begins, resolution may occur and this is best promoted by the continuous use of hot poultices, of which the ground slippery elm bark is the most eligible. Lachrymal fistula is occasioned by the imperfect healing of an abscess, and implies the existence of a permanent stricture. This Fig. 129. lesion is not seen as frequently as once it was, nor do lachrymal diseases often attain the extremity which the older writers describe. Surgical aid is better and more ready to be instituted than in the older day. Hence, a bad case of caries or of fistula does not often get an opportunity for development. It is needless to describe the condition—it declares itself; and if dead bone be present, the probe will soon discover it, if the foul odor and discharge do not betray it. Fig. 129 shows a case of lachrymal abscess and fistula during the regressive period. The fistulous opening afterward 20 306 DISEASES OF THE EYE. closed spontaneously, while the stricture was at a later period divided and treated by probes. For a bad case, cleansing by the syringe through the fistula may sometimes be proper, together with attempts to restore the calibre of the duct. If there be dead bone, this may be left to gradual elimination or be removed by a small gouge. For such cases destruction of the sac will generally be a necessity. In gen- eral, it is better for the great majority, to slit the canaliculus and deal with them as if there were no fistula. So soon as a route can be established for the secretions to make their way into the nostril, the fistula will heal. In case it prove sluggish, the process of clo- sure may be hastened by stimulating it with a pointed crayon of nitrate of silver (Squibb's caustic points). Cure of the stricture carries with it cure of the fistula. If the stricture be incurable, the obliteration of the sac is the alternative, in the manner above described. It may be remarked, in summing up the whole matter of lach- rymal troubles, that the larger number may be completely cured, another proportion are relieved of special annoyance, and the re- mainder gain some benefit, but still have trouble. That a perfect cure should always ensue, it would be unreasonable to expect; that palliation is better than no relief, is evident, while patient continu- ance and careful discrimination of the precise lesion, are indispens- able to success. Moreover, in no cases more than these, is the tactile address of the surgeon an element of value to win confidence and spare needless pain, and thereby contribute to success. A case reported by Dr. Bull (Am. Jour. Med, Sci., July, 1880) is worth remembering, where caries of the ethmoid bone caused a pre-lachrymal abscess, and on opening it the lachrymal sac was not involved, nor its cavity entered. In such cases there will be no epiphora. Treatment will simply be to provide for the escape of the discharge by washing out the cavity with antiseptic and slightly stimulating solutions. Leptothrix lachrymalis sometimes makes its home in the canal- iculi, especially in the inferior. The symptoms are slight inflam- mation and swelling about the punctum, suggesting a stye, and at the orifice a stringy mucoidal pus presents and can be squeezed out. There is swelling of the caruncle and semilunar fold and persistent annoying "angular" conjunctivitis. The somewhat tenacious se- cretion can be seen issuing from the puncta spontaneously; the apertures will be widely open and a sucking or pumping motion may perhaps be noticed. The secretion collects in flakes and small masses and beginning at the inner angle spreads over all the in- ferior cul-de-sac. While on the one hand the mistake may be made of regarding the condition as simply a hordeolum, on the other the case may be considered a mild dacryocystitis, There will be no dis- DISEASES OF THE LACHRYMAL APPARATUS. 307 tention of the sac, and the chronic character of the trouble excludes the diagnosis of a stye. The condition is somewhat rare, but occa- sionally appears. A very precise and ample description of it was given by Von Graefe1 in 1854, and again in 1855. By pressure a slimy yellow substance is brought out, but the swelling may not entirely disappear, because a number of small calcareous granules may remain. Microscopical examination shows a bacillary micro- organism, a fungus with jointed threads and spores, akin to the leptothrix buccalis which is found on the tartar of teeth and has the property of secreting lime salts. See Foster's " Encyclopaedic Medical Dictionary," Vol. III., 1892. Treatment consists in slitting the canaliculus to expose the cavity, emptying it, and applying a solution of nitrate of silver gr. v.-x. ad § i. for a day or two, and using a weak antiseptic solution as a lotion. So soon as the fungous character of the trouble is perceived, treatment will be readily un- derstood. A point to be noted is that only one eye is affected. Excessive lachrymation is caused sometimes by undue secretion of tears unassociated with disease of the excretory apparatus. This is by far more rare than the conditions above described. The epiphora is not constant, but appears when cold winds or similar irritation stimulates great conjunctival secretion. It may give no annoyance in summer or within the house, and be extremely trouble- some when facing a cold wintry wind. There may not be very marked congestion of the ocular or of the tarsal conjunctiva. There will be no swelling of the caruncle as uniformly attends catarrh of the sac, nor pouting of the puncta, nor can an}7 fluid be expressed from the sac The sedative effect of cocaine temporarily stops the annoyance, and if the upper lid be everted so far as the cul-de-sac (sometimes needing a forceps for the purpose and the aid of cocaine) a band of swollen conjunctiva will be found in or near the fornix betraying the enlarged and irritated glands of Krause, the isolated lachrymal follicles which are the source of the hypersecretion. Diagnosis is included in the above description, and treatment consists in applying solution argent, nitrat. gr. v. ad § i. to the site of the trouble twice weekly, or perhaps the more heroic method of slight touching with the actual cautery (Paquelin or a small gal- vano-cautery) will be admissible and more prompt. Nasal catarrh must be duly remembered. Extirpation of the lachrymal gland is scarcely to be thought of, although it was once practised by Mr. Laurence. This gland is not the source of the trouble, but the smaller ones referred to in the fornix. 1 Graefe, Archivf, Ophthal., Bd. 1, Abth- 1, S. 284, alsoBd, ii., Abth, 1, S. 224. CHAPTER IV. THE CONJUNCTIVA. Anatomy and Physiology.—The membrane presents for consid- eration its tarsal portion, the fornix or sinus, and the ocular por- tion. The tarsal or palpebral part is closely and smoothly adherent to the tarsi, and permits the Meibomian follicles to be seen through it. It has a faintly yellow color and a few vessels. The fornix, or sinus, or cul-de-sac, or fold of transition, is very loosely attached to the parts beneath, and slips freely back and forth; it has numer- ous folds, is of a turgid dark color, and has many glands. The depth of the fornix varies according to age and individual peculiar- ities. Sometimes the whole of the superior fornix can be exposed to view, by everting the lid, and often no effort will display it. The inferior fornix can always be fully seen. The ocular conjunctiva lies smoothly upon the globe, but is loosely attached, and can be moved back and forth by pulling upon the lids. At the outer can- thus the conjunctival sinus is deep, especially toward the lachrymal gland; at the inner canthus, on the contrary, the sinus, or fornix, is shallow both above and below. At the inner end of the palpe- bral slit we have the congeries of glandular follicles, called the car- uncle, and between it and the margin of the cornea is a slight fold of the membrane running nearly vertically, yet somewhat crescen- tic, called the plica semilunaris. It is bound rather firmly to the parts beneath, and is the analogue of the third eyelid of some animals, and in them it often contains a plate of cartilage. The caruncula lachrymalis is an isolated and modified portion of skin tissue covered by epithelium, containing fine hairs with their tributary follicles, and modified sweat glands resembling the glands of Moll. It also contains connective tissue and a little adipose sub- stance; it is dense and firm and of a pale red color. Both it and the semilunar fold are connected by fibrous tissue to the subjacent structures and in the movement of the eyeball inward, they are drawn inward with the action of the rectus internus muscle. This relation is too often made unpleasantly obvious by the sinking which occurs after tenotomy for converging strabismus. The different portions of the conjunctiva vary in structure. The tarsal part seems on casual inspection to be perfectly smooth, but THE CONJUNCTIVA. 309 closely examined, it is found to have a slightly velvety surface, and this is produced by numerous fine grooves and pits which reticulate irregularly, and constitute so-called papillae. The papillae are larger near the orbital edge of each tarsus. Their distribution is quite irregular. They are covered by epithelium whose super- ficial layer is cylindric and the deep layer flat. As the epithelium goes into the depressions between the papillae, it is in several layers and distinctly cylindric These depressions are irregular and complex in form. There is a layer of fibrous tissue beneath it, rich in elastic fibres and closely adherent to the substance of the tarsus. In the meshes of the fibres is diffuse lymphoid (ade- noid) infiltration which grows more abundant toward the orbital portion. Lymphoid tissue is gathered into distinct masses (Henle) and called lymphoid follicles, and is normal in many domestic animals, and whether their occurrence in man is to be counted normal or pathological is a subject of dispute. It is admitted that they do not appear in the young. That they may, when in moder- ate quantity, be considered normal in man, seems to be the best opinion. This question has a bearing upon the pathology of tra- choma. When the grooves and furrows of the tarsal conjunctiva are very deep and intricate, they form crypts and follicles lined by epithelium and may thus take on the appearance of glands. If their orifices at the free surface become occluded, they may resemble ductless glands. In young subjects the reticulations and furrows do not exist. The orbital part of the conjunctiva, the sinus or fornix, is loose and plicated, and both variable in extent and imperfectly defined in limits, except at the tarsal side. Its tunica propria contains abun- dance of elastic fibres. Its epithelium is in many layers, the sur- face cells are cylindric, those beneath are rounded and there are very few of the depressions described as present on the tarsal por- tion. The only glands are the acino-tubular of Krause near the upper edge of the tarsi, and there is no lymphoid or adenoid sub- stance. There is an abundant and loose submucous tissue. The ocular part of the conjunctiva has a flat epithelium in numerous layers and in this respect resembles that of the cornea. The tunica propria has no papillae and contains among its fibres many leucocytes. At the margin of the cornea the conjunctiva becomes closely united to the subjacent structure and its epithelium is more dense. This part is known as the limbus corneal, and it is about 2 mm. wide, but varies. The sub-conjunctival connective tissue is loose and elastic, although the membrane is held smoothly in place, and especially by fibres which run into it from the inser- tions of the recti muscles. The blood-vessels are very numerous in the region of the limbus, 310 DISEASES OF THE EYE. about the caruncle, and in portions of the tarsal conjunctiva, espe- cially at the outer and inner angles. The large veins of the ocular portion are to be noticed, especially those which go to the muscular twigs and empty into the ciliary body. The sensitive nerves of the conjunctiva are numerous, and come from the fifth pair. They form a special meshwork about the limbus, and in the tarsal portion special tactile bodies have been described by Krause. For this reason the presence of a foreign body beneath the lid is so intolerable, and reflex action between the orbicularis and the conjunctiva so prompt. The function of the conjunctiva is to act as a lubricating sur- face and in this it resembles the serous membranes. The fluid for ordinary needs comes by transudation from its vessels and glands and no demand is made upon the lachrymal gland except under special circumstances. The eversion of the upper lid may be most easily effected in the following way: The patient sits facing the operator, holds his head erect and looks at his lap, or the floor. Place the left thumb on the brow with its tip at the upper edge of the tarsus, while the other fingers rest on the forehead: gently press down the skin and with the other hand seize the border of the lid and bend it over the thumb nail as one would fold a piece of paper. When a patient offers no resistance one may turn the lid readily upon a pencil or a probe laid transversely across its orbital portion, but the thumb gives aid in forcing down the brow and skin and after eversion helps to extrude the fornix to view. A fuller exposure of the fornix is gained by pressing the eyeball backward through the lower lid as the cornea turns down and the eversion is maintained. As the globe is pushed backward the folds evert beautifully. If the lid be very short or swollen, or the patient rebellious, place one thumb at the upper edge of the tarsus, cover the tip of the other with a bit of muslin and pressing against the lid border push it up and over—one thumb aids the other. The muslin prevents slipping and the upper thumb catches the tarsal edge. For young children who make great resistance, lay them on the back in the mother's lap with the head between the operator's knees. Use the point of the forefinger as a fulcrum and with the other pull the lid over it. A bit of muslin will often be of service. It may be necessary to use an anaesthetic. Eversion of the inferior cul-de-sac is usually easy, but its complete exposure is secured by first having the patient look far down, then with the finger depress the tarsal edge and finally bid the patient look up—the cul-de-sac at once rolls out. Diseases of the Conjunctiva. According to Cohn's tables, 30$ of the diseases of the eye are furnished by the conjunctiva, and of these almost all are inflamma- THE CONJUNCTIVA. 311 tory. The phases of conjunctivitis are various, and numerous sub- divisions can be made according to the principles used in classifica- tion. It is better to do this so far as possible according to the pathological types presented. The general features of conjunctivi- tis (syndesmitis) are redness, cedematous swelling both in and be- neath the membrane, increase of secretion, which will consist of tears, serum, mucus, cast-off epithelium, and a greater or less amount of pus cells; there may be coagulable exudation upon or in the membrane; the lymphoid elements will be increased both in size and quantity, the papillary structure may be hypertrophied. It may be said that congestion and undue and abnormal secre- tion always exist in this inflammation and on the latter character- istic particular stress must be laid. It is also to be emphasized, that in general the secretions of conjunctivitis are contagious. For the milder forms this is measurably true, while in acute and florid types the contagiousness is extreme and the effect liable to be severe. In certain cases, viz., in most of the purulent and plastic types, the contagious element is a micrococcus of a distinct char- acter. Communicability resides not only in the secretions, but in some forms, seems to pervade the atmosphere, giving rise to endemic inflammations in asylums, homes, and hospitals, and in them the disease is prone to exhibit or degenerate into various pathological phases grouped under the name of granular conjunctivitis. We may make the following subdivisions: 1st hyperaemia of the conjunctiva; 2d, conjunc simplex or catarrhalis; 3d, conj. purulenta or blennorrhoica; 4th, conj. crouposa; 5th, conj. diphtheritica; 6th, conj. granulosa; 7th, conj. phlyctenulosa. To these inflammatory types we add, 8th, xeroma; 9th, lymphangiomata; 10th, hemor- rhage; 11th, wounds and burns; 12th, tumors and ulcerations; 13th, subconjunctival emphysema. Conjunctivitis. 1st. Hyperaemia palpebralis is frequent, may be acute or chronic, and is usually symptomatic. Mere hyperaemia of the ocu- lar part of the membrane is rare and apt to be traumatic. Yet there are persons who get a mild attack of this sort for which they apply a cold compress at night and find their eyes quite well in the morning. They are usually affected with nasal catarrh. Hyper- aemia of the tarsal conjunctiva is not seldom incorrectly called granular conjunctivitis, because the surface may be slightly more velvety than usual. The outer and inner angles always show the deepest congestion, while along the middle of the tarsus the vessels, both the large and fine, give a decidedly pink hue to the usually yellowish-pink surface. There is commonly only a trifling increase of secretion, almost no increase of thickness, and the papillary struc- 312 DISEASES OF THE EYE. ture is developed no more than may be compared to the surface of fine emery paper, and the transparency is not lost. Complaint is made of dryness, of smarting, pricking, or gritty sensations: per- haps the lids cannot be kept fully open, there may be some photo- phobia. The symptoms are worse at night and are aggravated by use of the eyes. The most annoying cases of this kind are those which are caused by various forms of eye strain. Whatever makes vision difficult, excites this hyperaemia. We see it in those who use their eyes to excess, for long hours, or late at night, in those who have wept extremely; in those who have errors of refraction, such as beginning myopia, or hyperopia, or astigmatism, or anisometropia or spasm of accommodation, or beginning presbyopia; in those who suffer from fatigue of the motor muscles (muscular asthenopia in various types). We see it with faint opacity of the middle of the cornea, with incipient cataract, or diffused haziness of the vitreous. It accompanies chronic ophthalmia tarsi, which is itself often occa- sioned by refractive or muscular errors. It is often coincident with chronic nasal catarrh, and if this develop at times into acute activity as "hay fever" or "rose cold," etc., the palpebral hyperaemia cor- respondingly increases and may grow to active conjunctivitis. Those who work in dust, such as millers or street sweepers, etc., naturally have this condition, and it always attends the lodgment of a foreign body under the lid. There is a chronic type of the dis- ease found chiefly in old persons whose eyelids are baggy and who may have ectropium. It always co-exists with catarrh of the lach- rymal sac and stricture of the nasal duct. Among all these sub- jects those who complain most will be the asthenopic persons, and the more excitable they are, the more will they emphasize their troubles. Treatment.—The important point is to ascertain and remove the cause. It may disappear upon receiving suitable glasses for refractive or muscular errors, upon the removal of a foreign body, upon the subsidence of a stye, the removal of a cyst of the tarsus, or the cure of nasal catarrh. Concurrently with the proceedings hinted at, direct remedies may be called for which will be both soothing and mildly stimulating. Weak solutions of common salt, half a teaspoonful in a pint of water, the addition of a few drops of brandy to a tumbler of water, or as the fashion now is, of " Pond's extract" (fl. extr. hamamelis) in quantity varying from a few drops to a teaspoonful in a glass of water, are in popular use. The cold douche from a fine rose jet arranged as may be convenient or spray of cold water from a double-bulb spray apparatus, are often grateful and to it the addition of a few drops of bay rum gives more efficacy. Some of the usual prescriptions are as follows: I> Sodae biboratis pulv., 3i.; aquae camph., § vi. 5 Acidi borici 3i.- THE CONJUNCTIVA. 313 aquae, ? vi. $ Zinci sulph., gr. ij.; aquae, 5 iv. B Fl. ext. opii., 3 ij.; aquae, \ iv. These mixtures are to be dropped between the lids by a dropper or may be put into an eye cup which is to be held to the eye and the lids being opened, the fluid remains for half a minute or more in contact with the globe. Afterward it may be' applied by a compress to the outer surface of the lids for ten minutes. Such applications are made morning and evening, or at such times as the patient prefers. If such measures do not remove the irritation, applications directly to the tarsal surface will be in order, and the surgeon must evert the lids. For this purpose a solution of nitrate of silver, gr. ss.-ij. to water 3 i. or in chronic cases, tannin, gr. x., glycerin, 3 i., or a smooth crystal of alum may be empoyed every second or third day. It is sometimes useful to apply to the tarsal border at night a weak mercurial ointment, such as, 1> hydrarg. oxid. flav., gr. ij.; vaselini, 3 i.; or t> Unguenti citrini, gr. ij.; vase- lini, 3 i.; vel cosmolini, 3 i., in lieu of the "touching" of the lids and often in connection with some of the above-named collyria. The mixture of borax and camphor water is most frequent and is widely known. Solution of tannin in glycerin, gr. xx. ad 3 L, may be ap- plied by a spray apparatus (Agnew). 2., Conjunctivitis simplex vel catarrhalis.—It is necessary to allow considerable latitude to the definition of this inflammation, because we meet it in various degree and phases. One might make of it three subdivisions, viz., C. Simplex, C. CEdematosa and C. Catarrhalis. The first is attended by little swelling and presents chiefly hyperaemia. The second is not frequent and exhibits little redness, but abundant serous effusion in and beneath the conjunc- tiva and in the lids. It occurs in young subjects of delicate and lymphatic habit, is not much painful and there is little sticky secre- tion. The membrane shows little vascularity and the prevailing tone of color is a tawny yellow. This occurs idiopathically, while precisely similar conditions accompany some cases of periostitis and other orbital inflammations. The third is the typical and usual form of catarrhal conjunctivitis and has the following appearances. Increase of vascularity both palpebral and ocular; on the globe the mesh-work of vessels forms close and irregular spaces and is somewhat closer near the cornea, the hyperaemia is nearly equal in intensity over all parts of the eye. There will be more or less effu- sion in and beneath the membrane, and pressure with the finger through the lid will move it about. There will be swelling of the lids and inability to fully open them, and some redness along their margins. But the striking and special symptom is the abnormal secretion which glues the lashes into bundles and the edges of the lids together after sleep, which is flocculent and turbid, a mixture 314 DISEASES OF THE EYE. of serum, tears, mucous epithelium and of some pus-cells. It collects in flakes and spreads in a thin layer upon the tarsal surfaces. When everted, the palpebral surface is deeply and uniformly red, succulent, and velvety. At the edge of the cornea there are often minute erosions and a fringe of vessels may after a time develop around its whole circumference and reach one or two millimetres into the transparent cornea. Sometimes there are minute hemor- rhages in the ocular conjunctiva and the color of the hyperaemia varies from a bright scarlet to a deep mahogany. The subjective symptoms vary according to the severity of the attack and the sensitiveness of the patient. There is heat, and burning pain, with pricking and itching and the constant sense of heaviness and of sand in the eyes. At the outer and inner angles these feelings are most pronounced and often the skin after a time becomes ulcerated at these sites, to the aggravation of the sensa- tions. The flow of scalding tears and the persistent collection of the secretion provokes constant use of a handkerchief and there is often marked photophobia. The symptoms are apt to be worse at night and better in the morning. Usually both eyes are affected. A form of this inflammation called by English writers catarrho- rheumatic ophthalmia seems to be a mixture of conjunctival and scleral inflammation. The secretion is more watery than sticky, there is a deep as well as superficial vascularity, and then there is acute pain in the globe, the temples, and forehead, added to the usual burning sensations. The eyeballs are tender to the touch, there is usually extreme photophobia and the sufferings of the patient are out of proportion to the apparent severity of the dis- ease. Such persons are apt to be gouty or rheumatic. Many times there is little discomfort experienced with catarrhal conjunctivitis, and especally in healthy persons, and frequently the services of a physician are not called for. The disease is idiopathic or symptomatic and in a few cases it seems to be metastatic. It comes from atmospheric causes, from the foul air of ill-ventilated rooms, from exposure to dust, smoke and heat. It is apt to occur at the seaside in the summer, from heat, glare, and dampness. Workers at the forge, millers, cigar-makers, moulders are its especial subjects. It is frequent in orphan asylums and crowded eleemosynary establishments. It is often part of the attack in acute coryza and in hay-fever or rose cold. Sometimes epidemics occur and are thought to be more frequent in the spring and autumn. A special type of acute conjunctivitis, usually called papillary, sometimes follicular, both which names indicate the differing phases set up by the same cause, comes in certain persons from a solution of sulphate of atropia. (Note previous remarks, p. 240.) With a THE CONJUNCTIVA. 315 few who are remarkably susceptible a single instillation suffices. Generally it must have been kept up for some time before this re- sult appears. There is often erythematous inflammation of the skin of the lid and of the cheek. The conjunctiva will exhibit besides redness and hypersecretion, enlargement of the follicles in the tar- sal folds. The attack promptly abates on withdrawal of the atropia. Furthermore we have epidemics of catarrhal conjunctivitis, usually of mild type with moderate quantity of secretion from the eyes and attended by coryza. The attack lasts usually from three to ten days and may be widespread in the community. It is pop- ularly known as "pink eye" and evidently resembles the "distem- per " of horses and other animals. Dr. John E. Weeks has studied its micrography and found it to be a germ disease communica- ble by contagion. He has isolated its special bacillus in pure cultures.1 We have mild conjunctivitis during extreme summer heat, espe- cially if combined with exposure to the sand of the desert, or the beach, or the arid dust of the plains. It happens to travellers among arctic snows. Facing the glare of the electric light will produce it: if the light is properly diffused no harm results. The symptomatic or secondary forms of the disease are numer- ous, as in dacryocystitis, acute and chronic, in hordeolum and ab- scess of the lid, in erysipelas, in eczema, in herpes zoster frontalis, in all the exanthemata, as measles, scarlatina, variola, and vari- cella. It is a serious and most annoying complication In acute eczema of the face, especially in old persons, and is utterly rebel- lious until the subsidence of the skin disease. It is an early token in measles, while in scarlet fever it comes during the later stages of the eruption, and similarly with small-pox. Certain fugitive attacks in cases of gonorrhoea (Haltenhoff) seem to be metastatic, expressly excluding their production by the conveyance of secretion, and this opinion is founded upon the nature of the attack, its mildness, its short duration, the absence of the purulent secretion, and (of obviously less value as evidence) upon the negation by the patient of any carelessness on his own part. There may "be coincident inflammation of the joints (gonorrheal). Such occurrences are rare. Cases have been observed in which a mild conjunctivitis has preceded each menstruation. Dr. W. O. Moore related such a case to the New York Ophthalmological Society. Duration, Complications, and Sequelae,.—There is a notable tendency to spontaneous recovery, and the duration of the disease will be from a few days to three weeks. If, however, the surround- ings be unfavorable, or if no care be taken or the person be cachectic or of bad habits, it may become a chronic malady. This is apt to 'Knapp, Arch, of Ophth., xv., p. 441, 1886. 31G DISEASES OF THE EYE. be the case among tenement houses, and in badly managed institu- tions, where a seemingly mild attack refuses to get well, and passes over into a state of thickening and infiltration of the tarsal and orbital portions of the membrane, with hypertrophy of the papillae and of the epithelium; a condition conveniently called granular conjunctivitis, and it is extremely obstinate although it may not seem to be severe. Again a simple attack in old persons is apt to degenerate into a chronic condition, and hard drinkers have been noted since the time of Solomon for " redness of eyes." It is rare that the cornea becomes affected, save in the moderate way above denoted. After measles the eyes are liable to remain irritable for a long period, and while no vigorous treatment seems needful, care in abstaining from use is required. It is generally true that the eyes are apt to be irritable for several weeks, even when a case has seemed to recover well. The possibility of granular conjunctivitis ensuing under special conditions has been mentioned and it is also possible for persons who give no attention to cleanliness, especially if aged, to have chronic blepharitis, lippitudo and ectropium, and perhaps impairment of the integrity of the cornea. Treatment.—The first and chief consideration is scrupulous cleanliness, and where an endemic has broken out in an institution, the removal of the affected into large and well-ventilated rooms, and giving each abundant air space. Simple cleansing of the eye from all secretion by mild lotions is often all that is required. The first question always is, what should be the temperature of the fluid? That may be left to the sensations of the patient, whether it shall be lukewarm or cool, but as to the mode of application instruction must be given that it shall remove the secretion and not retain it within the lids. Hence, poultices, tight compresses, bandages, raw oysters and a farrago of disgusting popular remedies must be pro- hibited. It is also prudent to discard sponges, because they are apt to become means of contagion. A simple compress of linen or muslin, or a pad of absorbent cotton wetted in the fluid, may be applied for fifteen minutes or more at intervals of one or more hours according to the seriousness of the case. It should be wetted afresh every three or five minutes and the secretion gently wiped away from the edges of the lids. The purpose is to keep the eye clean, to remove and antagonize septic elements and to exert by the lotion a moderate control over inflammatory action. For mild cases a cool lotion, for more severe a cold lotion will be chosen. Nothing serves so well in the great majority of cases as a 3$ solution of boric acid. It need not be accurately prepared, but the patient may be told to put a teaspoonful of the crystallized acid in half a pint of water and use it copiously. If the amount of secretion require, it may be squirted between the lids by a dropping tube ora small bulb. It is THE CONJUNCTIVA. 317 grateful to the inflamed surface and is of undoubted value. For a very large number of cases it fully meets the purpose and it has grown to be the stock prescription in the practice of the New York Eye and Ear Infirmary. It must not be forgotten that in all mild cases of conjunctivitis the diseased condition is of short duration, and that amid healthy surroundings a complete and prompt recov- ery is the natural order of events. Many persons prescribe for themselves weak sulphate of zinc solution dropped in the eyes at night. We therefore will carefully avoid unnecessary treatment, and especially any strenuous or harsh measures, which while they exhibit zeal, are in reality evidence of indiscretion. Under this cat- egory may be put leeches and blisters and the use of irritating " drops," etc. The treatment will be aimed at the uncomfortable symptoms. Under this head may be classed the cleansing of the eye, as has already been stated: before going to sleep the edges of the lids may be smeared with simple cerate, or unperfumed cold- cream, or vaseline (the last melts and disappears very soon), the same may be rubbed over the skin of the cheek or lids if the surface is irritated by frequent wetting. If there be much discomfort from feelings of grittiness or heat or smarting, a 2f0 solution of hydro- chlorate of cocaine may be dropped between the lids at intervals of ten minutes until the sensations are allayed. This remedy has also the happy property of contracting the blood-vessels, thus serving a double purpose. It is, however, not to be used except to relieve discomfort and not with great frequency. Many cases will require no other measures and a few days will see the eyes restored to health. For cases of more severity with a little swelling of the lids, slight sub-conjunctival effusion, more copious secretion and more pain, it may be needful to employ in • addition astringent solutions. Among the oldest is a mixture of acetate of lead with infusion of opium, a drachm of the former to a pint of the latter. It doubtless has useful properties, but it must never be used when there is any tendency to ulceration of the cornea, because the lead is liable to be precipitated upon it. Its utility is in the early stage of a somewhat acute attack, and then is most grateful if warm. The mixture should be strained and made clear. It may be made also as follows: r> Liq. plumbi sub- acetatis, 3 ij.; Fl. ext. oph. deodorat., I i.; Aquae, 3 vi. M. A solution of alum, a drachm to the pint, is with many a favorite application both inside and outside of the lids. Mr. Tweedy, of the Royal London Ophthalmic Hospital (Moorfields), and some others have asserted that it has a tendency to increase ulcerations of the cornea in virtue of a solvent effect upon its cementum. He thinks he has seen de- cidedly mischievous effects of this kind. For myself I have almost discarded alum in favor of boric acid, and when the quantity of 31S DISEASES OF THE EYE. secretion or the intense redness, or the degree of effusion call for active interference, the nitrate of silver is the most satisfactory remedy. A solution, two grains to the ounce, £#, may be dropped into the eye twice daily from a dropper. If the tenderness and swelling do not prevent, the same solution, or one five grains to the ounce, lfc, may be applied with a small brush to the everted lids once daily, or be dropped into the eye. It causes a littie pain, for which a solution of cocaine may be used, and compresses dipped in iced water sedulously applied until the reaction subsides. For very nervous patients it may be needful to resort to bro- mides, and possibly to mild closes of morphine or Dover's powder at night, or better still to phenacetine, gr. x., once in two hours. It is sometimes well to add sulphate of zinc to boric acid in the later stages of a moderately severe attack, as for instance: $ Zinci sulphatis, gr. iij.; Acidi boric, 3 i.; Aquae, 3" vi. One may resort to solutions of corrosive sublimate, from 1 to 3,000 to 10,000, as was formerly done, and this would be suited to the mild epidemic cases, and to hospital or tenement-house out-breaks. It is irritating to many patients, but it is effective. For cases where cedematous infiltration is great and secretion moderate, as in delicate children and sometimes in old people, solu- tion of tannin, gr. v. ad 1 i., or the liquor plumbi subacetat., 3 ij. ad 3 viij., is well adapted. For severe cases of so-called " catarrho-rheumatic ophthalmia " it may be needful at the outset to apply two or four leeches to the temple to allay pain, to make very hot fomentations for the first day or two, to employ sol. sulphat. atropiae, gr. ij. ad 3 i., two or three times daily in the eye, and also perhaps a 2$ solution of coca- ine. No astringents or irritating drops are to be used until muco- purulent secretion is set up, and the temperature of all applications must be comforting to the patient. A saline purgative and often small doses of Rochelle salt frequently given for diuretic effect, will be valuable. In these cases we have to do no doubt with a general dyscrasia. Especially must one look for symptoms of a gouty dia- thesis, of which the signs may be slight and the tendencies not readily admitted by the patient. As the acute attack subsides, if there be left a state of chronic hyperaemia, one may touch the everted lids once daily with solu- tion of nitrate of silver, gr. ss.-ij. ad 3 i., or with a smooth crystal of alum. Or if a patient cannot be so frequently seen he may drop into his eye a solution of zinc sulphate and boric acid. A patient never should have a solution of nitrate of silver given to him for this purpose. It soon decomposes, and its prolonged use causes brownish discoloration of the conjunctiva (argyria conjunctivae). It need hardly be said that during an acute attack a patient THE CONJUNCTIVA. 319 must not read or write or smoke, and will remain in a dimly lighted, well-ventilated room. Even when recovery has been attained, cau- tion must be given against prolonged use of the eyes, especially at night, and against exposure to wind, dust, smoke and foul air. Often colored glasses (light smoked or blue) will have to be worn in bright light. In healthy persons with favorable surroundings and with proper care, the outcome of acute catarrhal conjunctivitis is perfect recov- ery within periods varying from five days to three weeks. On the other hand, there may be ulceration of the cornea with its various possibilities, or there may be chronic thickening of the palpebral conjunctiva, ectropium, pterygium, etc., etc. These conditions have been or will be considered under proper heads. Not a few cases of so-called granular lids have originated in an acute conjunctivitis. 3. Conjunctivitis purulenta, Blennorrhcea, Pyorrhea.— This phase of acute conjunctivitis is of more severity than the foregoing and present itself at different ages: first it occurs in infants at or soon after birth, and secondly it occurs in adults. In both classes the disease is essentially the same, and originates from contagion in the great majority of cases, but it is convenient and customary to consider them separately. The first is commonly called Ophthalmia Neonatorum.—At birth the eyelids are always ag- glutinated by the parturient secretions. It is common too for the lids to remain red and sticky for a day or two. The nurse washes them off with warm milk and water, and soon the eyes are clear. A little attention may be required for several days, the principal point being the careful removal of secretion as fast as it may appear, and soon all is well. Should there be a little swelling of the lids, and secretion be rather troublesome, a compress wetted with a solution of borax or of alum may be laid on the eyes for fifteen minutes, once in two or four hours, and the edges of the lids smeared with simple cerate or vaseline. The great proportion of the cases of this disease will not require serious attention, and will not cause the physician any anxiety. A physician in large obstetric practice told me that he had had only one serious case in an experience of twenty years. But there are cases even in private practice which need active attention. Of these I have seen two varieties. The less frequent are some which have more the character of granular than of purulent conjunctivitis. There is very little swelling of the lids—secretion is almost wholly watery. There is little or no hyperaemia of the ocular conjunctiva, while the palpe- bral conjunctiva is reddened, and at the fornix is considerably thickened and swollen. This hypertrophy is the essence of the trouble. It is truly a form of follicular conjunctivitis occurring at an exceptional age. While this continues the eye keeps watering 320 DISEASES OF THE EYE. and a little sticky, and the condition goes on for weeks. The cornea does not get hazy, and there is no special danger. For the milder cases, where an anxious mother insists on something being done for the baby, I deprecate anything more than washing with a solution of boracic acid several times a day. But if a child is a month old, and the discharge continues and the fornix exhibits decided swelling, I have been obliged to use solutions of tannin and glycerin as strong as 3ij. ad 3 i. before the condition would yield. I had tried nitrate of silver in mild solution, and, unwilling to make it more caustic, had taken a solution of tannin, gr. x. ad glycerin, § i.; but this had only a temporary good effect, and the disease was not subdued until the strong solution was applied. It was done every second day to the everted lid, and was of course quite painful. Much more important is the purulent conjunctivitis which is generally spoken of as ophthalmia neonatorum. It presents itself under various degrees of intensity, with swelling of the lids, with yellow, thick secretion issuing from the eye, or, if dried upon the tarsal edges, it glues the lids to each other, and the conjunctiva, both ocular and palpebral, is reddened and swollen; at the begm- ning the secretion is comparatively thin, but soon it becomes thick and creamy. This quality indicates abatement in the ac- tivity of the process. There may be chemosis, and the palpebral conjunctiva be thickened and intensely red and spongy, with ridges and prominences, and be cleft by fissures between the en- larged papillae. The tumidity of the palpebral conjunctiva, which increases up to the fornix, is a notable feature. The cornea may remain clear, but its integrity is the object of anxiety. Its inva- sion may show, as the first sigh, a diffused haziness, or a single spot of purulent infiltration, or an ulceration; while in weakly infants, of whom premature births and foundlings are often extreme exam- ples, the cornea may suddenly break down with general infiltration, and become a mass of yellow putrilage. The place of ulceration in the cornea may be anywhere; if upon the periphery, and if it per- forate, the iris falls into the opening and becomes permanently adherent, and from this a partial staphyloma may ensue; or, in case of less extensive destruction, nothing more than a distortion or concealment of the pupil. Should the ulcer be central, and not too large, so that if it perforate and the sphincter iridis cannot be drawn into the opening, the lens will then come forward and rest in contact with the posterior surface of the cornea. Sometimes a fistula will give rise to prolonged contact of the lens-capsule with the cornea. As a consequence, there will be an opacity reaching a little into the centre of the lens, at its middle a small white dot and around it will be a fainter zone, and the whole will be apparently two or three millimetres in diameter. Sometimes, long after the THE CONJUNCTIVA. 321 eye is well, a fine thread is seen running from the lens to the mid- dle of the cornea, which is the attenuated vestige of the material deposited while the surfaces were in contact. The opacity belongs to the capsule chiefly, and is both upon it and overlaid by it, some- times having a distinct pyramidal form. It will be again referred to in speaking of cataract. In cases so marked as the above the secretion will be thick, creamy, and copious. The patients do not seem to suffer much pain, and usually nurse well. The skin of the cheek is apt to be excoriated by the discharge. Pi-ophylaxis.—The importance of preventing this disease will be appreciated from the statistics given by Haussmann.1 Of the inmates of blind asylums the number made blind by this disease was in Copenhagen, 8$, in Berlin, 20$, Vienna, 30$, in Paris among 208 blind young subjects, 45$. In 1876 it was shown that among the young persons admitted to the blind institutions of Germany and Austria, 33$ had been made sightless by this disease. In dif- ferent countries the variation was from 20$ to 79$ (Horner). In Philadelphia, Dr. Harlan found in 1871, out of 167 inmates of the blind asylum about 20$ had been admitted for this cause. In oph- thalmic clinics, Hirschberg had among 21,040 new cases 314 of this kind; Scholer among 10,000,156 of this kind. Horner in 1862 found among 10,000 cases, 161 of this variety and he gives this interesting analysis. Of recent cases there were 108, and of old cases in whom the disease had terminated, there were 53. Of the last named 53, 14 Avere blind in both eyes, 24 blind of one eye, and 15 had more or less serious corneal opacities. Of the 108 active cases only 24 were brought during the first week of the disease, and the remainder, viz., 84, came at later periods. Of the 24 cases seen during the first week, 2 already had corneal trouble; one healed with a trifling opac- ity, the other died before the end of the disease;—22 recovered with perfect sight. Out of the 84 less recent cases, 38 had disease of the cornea, and 46 did not have it. Of the 46, 3 acquired corneal ulcerat ion, but in none of these patients was the eye lost. For the statistics of lying-in hospitals on this subject, reference may be made to Haussmann, 1. c, and to Crede, "Die Verhiitung der Augenentziindung der Neugeborenen," Archiv f. Gyndkol, XVII., 1, S. 50 (also in separate form, Berlin, 18S4). The attention which of late years has been given to prevention of contagion, has proved by its success that to this, we are to look in the great majority of cases for its cause. The origin of the contagion is the morbid vaginal secretions. The healthy secretions of the parturient state do not produce the eye trouble, at any rate there is strong reason for this belief, both from general experience and because direct inoculation of healthy 1 "Die Bindehaut-Infection der Neugeborenen," Stuttgart, 1882. 21 322 DISEASES OF THE EYE. secretion has been practised without evil effects. Microscopic study has found that both in the morbid vaginal secretions and in the pus flowing from the eye a special organism appears which was first pointed out by Neisser, of Breslau, in 1879 (Centralblatt fur Med. Wissensch., No. 28), and called by him the gonococcus, because it is characteristic of gonorrhoea of the urethra. This kind of infec- tion is in the great proportion of cases the cause of the infantile disease. Other infectious causes cannot perhaps be absolutely ex- cluded, such as the lochial secretion, or that from a suppurating navel, while from the nature of the case few investigations are made on this point, and it is also impossible to prove a negative. The eye disease appears usually about the third day, but may be delayed as late as the eighth day. The prophylactic measures to be employed are on the one hand the washing of the vagina for some days before parturition, and while labor is going on, with a 3$ solution of carbolic acid in all cases where the secretions are of a suspicious character. On the other hand attention is to be given to the eyes of the infant. By some,washing the outer (not the inner) surface of the lids and the eyelashes with a 3$ carbolic solution is practised, while in accord- ance with the recommendation of Crede a single drop of a 2$ solu- tion (gr. x. ad 3 i.) of nitrate of silver is dropped between the lids of each eye by a glass rod. The effect of these measures has been to reduce the frequency of the infantile disease in the lying-in hos- pital of Halle from 12$ to 3$. In the lying-in hospital of Leipsic, where Crede instituted his own method, the cases fell from 7.5$ to 0.5$. It is impossible to resist the force of these facts and it becomes imperative to employ such measures in all cases where any suspi- cion may arise. This holds good especially in hospitals and lying-in wards, but it is applicable also to practice among the uncleanly and the poor. The solution of nitrate of silver in such strength, 2$, excites irritation, but a very small quantity is intended to be used (a single drop) and it neutralizes the poison. A 1$ solution will certainly suffice, and the rigorous proceedings of a public lying-in hospital do not fully apply to private practice. For infants where only the usual secretions are present, cleansing the lids and eyes with a solution of borax or with any mild antiseptic solution or with warm water will suffice. It is seldom but that both eyes are infected at the same time. In case one only is inflamed, the other should be hermetically closed, and this can best be done by strips of india-rubber plaster, which may be left on for forty-eight hours and then renewed. The disease is usually more severe in the eye first affected. Treatment.—If seen at the very beginning when the swelling of THE CONJUNCTIVA. 323 the lids and a watery secretion are the chief symptoms, nothing but cold lotions and assiduous cleansing are to be employed. Be- sides the attested clinical value of cold lotions, Weeks found that a low temperature destroyed the vitality of the germs which he isolated in simple catarrhal conjunctivitis; the same is true of the more virulent types now considered. For the cleansing, boric acid 3$ solution may be used. With the head upon the lap the solutions is to be squeezed from a rag or from a mass of absorb- ent cotton between the separated lids, and if needful is wiped away with a camel's-hair brush. The wetted cotton may be pressed lightly on the closed lids to squeeze out the flocculent secretion, and this is to be repeated as often as accumulation occurs. The cold application consists in laying linen or well-washed cotton compresses in iced water or on a block of ice, and transferring them every few minutes to the eye. In moderately severe cases the water need not be so cold. But the lotion is to be kept up day and night. As soon as the secretion grows a little thicker and the swelling of the lid grows less, so that it can be everted, we are to resort to nitrate of silver in strength varying from 1$ to 2$, gr. v. -x. ad 3 i. This is not to be dropped between the lids because it will thus endanger the cornea. But the upper lid is first to be everted, and if difficult to do, as often is true, the tip of the finger may be wrapped in a bit of rag or in the corner of the towel to aid in pushing or pulling the tarsal edge against the finger of the other hand which pushes down the brow. The physician has the back of the child's head between his knees and is provided with water and bits of rag. All secretion is to be wiped away and the caustic solu- tion pencilled over the exposed palpebral conjunctiva, carefully avoiding the cornea. Afterward the lower lid is to be similarly treated. The effect of the solution is in proportion to the quantity applied and the lid should be washed with water afterward. If there be a little delay in the washing, the caustic effect is greater. The degree of effect can be estimated by the degree to which the surface is whitened, and repeated pencillings will intensify it. With weak solutions one may obtain various degrees of caustic action. Such a proceeding is to be gone through once in twenty- four hours, very seldom will it be required once in twelve hours. Immediately after, iced cloths are to be applied and very frequently renewed until the cries of the child cease and the pain has presum- ably disappeared. For several hours the secretion is held in check, although the swelling increases, and during all the time of its in- crease and of the painfulness of the eye, the cold is to be continued; this may be for two or four hours. After a time flocculent portions of the eschar and renewed secretion appear. Now cleansing is in order and the lotions will be kept up with less assiduity as the 324 DISEASES OF THE EYE. swelling abates. If the daily personal attendance of the physician is not possible, a solution gr. v. ad 3 i. may be dropped between the lids three times daily, taking pains to insure its entrance beneath the upper lid by lifting it off the globe and at the same time avoid- ing contact of the caustic with the cornea. It is not easy and is very important to inspect the cornea, to watch the first tokens of its invasion. To separate the lids, Desmarres' elevators are inval- uable (See Fig. 130). In skilful hands what is known as the mitigated caustic stick (one part nitrate of silver with two parts of nitrate of potash) may be usefully employed. It is more energetic than solutions, it can be more accurately applied and finds its special utility in the later stages of the disease when papilliform swelling is extreme, and the secretion is very thick. Tlie cornea must be absolutely avoided Fig. 130. and the excess of caustic washed away. In ophthalmic clinics this is in considerable use. Frequently the conjunctiva bleeds under the handling; it is not, however, needful to resort to scarifications, nor is canthotomy to be practised. In infants, despite the great swelling, there is little danger of strangulation of the tissues, and leeches are never to be employed. In the event of the cornea having become affected, whether by opacity or by superficial ulceration, the caustic treatment is not to be interrupted, neither is it to be made more vigorous. If deep ulceration take place a solution of atropia, gr. ij. ad 3 i., may be dropped into the eye three times daily or oftener, to secure dilatation of the pupil. For marginal ulcers, eserine sulphate gr. i. ad 3 i. may be used twice daily according to effect, and atropine during the interim. If the ulcer threaten to perforate, a careful paracen- tesis at its thinnest point will sometimes do good, but one rarely has an opportunity to try it and it is always a delicate and difficult thing to do. On the other hand, if perforation spontaneously occur, there is generally an improvement in the condition. It is not meant that spontaneous perforation with the resulting prolapse of the iris is not to be deplored. Temporarily it affords relief, but it brings about permanent damage to sight. It is unwise to interfere THE CONJUNCTIVA. 325 with prolapse of iris unless it projects in a conspicuous prominence, when sometimes careful puncture, holding the needle at a tangent to the summit, will abate it. Excision is not to be practised. In l)ad cases the whole cornea may rapidly melt down, the iris exten- sively prolapse, the tissues rupture, and the lens escape. A staphy- loma of the cornea or phthisis of the globe may eventuate. Some writers have reported favorably upon finely powdered iodoform dusted over the everted lids (Grossman1 and others). It is said to check the discharge and have a favorable effect on the cornea after infiltration has begun. It is applied once or twice daily. Since its announcement in 1882, little has been said about it. The duration of treatment in favorable cases will be from four to six weeks, while in bad cases it may go on much longer. The length of treatment and the prognosis as to result are greatly in- fluenced for good or bad by the health of the subject and by effi- ciency as well as early commencement of the treatment. But even in cases which seem most unpromising the wonderful recuperative powers of early life, will eventually bring about a degree of im- provement for which there seemed to be no prospect. Sometimes the conjunctiva takes on extreme hypertrophy; the purulent secretion almost ceases, the cornea may be clear, the activ- ity of the disease is at an end, but there has not been subsidence of the swelling, and a constant eversion of the lids remains (paraphimo- sis.) It does little good to apply caustics or stimulants or astrin- gents. The lids may be inverted, but in a moment or certainly as soon as the child cries, the deformity returns. Nothing relieves this condition but mechanical methods. The lids must be inverted and so retained by strips of india-rubber plaster, and their ends may be held down by laying over them a few fibres of cotton and saturat- ing this with contractile collodion. In fact such a dressing may cover the whole of the lids save a spot for secretion to escape. Should this fail after a fair trial, and it is not likely to fail, one might in a severe case carefully pare the edges of the lids over the middle third without doing injury to the cilia and stitch them to each other. They will grow fast and may so remain for several weeks until the hypertrophy has disappeared. I should give sev- .eral weeks' trial to the other method, provided the dressing could be kept in place without irritating the skin. It must be renewed every three or four days. Purulent conjunctivitis in adults (gonorrhoealophthalmia), is essentially the same disease as above described in infants. In a few instances it seems to be of spontaneous origin, but these are very rare, while in the vast majority some source of contagion can be traced. This will be from an acute or chronic gonorrhoea either 1 Ophthalmic Review, Vol. i., 1882, p. 214. 326 DISEASES OF THE EYE. in the male or female, by communication from a similarly diseased eye, by indirect contact through the fingers or handkerchiefs, tow- els, clothing or rags. The secretions from diphtheritic conjunctivitis or from vaginal leucorrhoea cause it. A very minute quantity is sufficient and that derived from an old gleet remains effective. The right eye, for obvious reasons, is oftener concerned than the left. More frequently than with infants is one eye only involved. Reference has been made to the gonococcus Neisseri as the effi- cient agent in this disease. The micro-organism appears usually as diplococci in twos or fours within the pus-cells, or in isolated groups, and are also found at considerable depth in the epithelium and in the tissue of the conjunctiva. Their malignant influence has been unquestionably demonstrated by the fact that inoculation with pure cultures causes urethritis in the human subject. Moreover, Deutschmann reports a case of arthritis gonorrhoica in an infant with purulent ophthalmia (Graefe's Archiv, XXXVL, 1, 114, 1890). The cocci were in the conjunctival secretion and in the fluid ob- Fig. 131. tained from the joints by puncture. In the eye, the more active the gonorrhoea at the time of infection, the more violent will be the inflammation. The period of incubation is said to be about forty- eight hours. A physician must always be careful lest he incur infection. Sometimes pus spurts out in a jet as the lids are sepa- rated. Immediate washing and neutralizing by a drop of 2$ solu- tion of nitrate of silver will be indicated. The mystery which sometimes attaches to the transmission of the inflammation to a healthy eye is lessened, when it is known that the pus diluted 1 to 1,000 still retains decided contagious properties. It ought also to be stated that nitrate of silver, by its power of coagulating albumen antidotes in high degree the noxious character of the pus, and it has been shown that a one-fourth-per-cent solution, or gr. £ ad z i. renders it innocuous. This fact explains why so few cases of con- tagion occur in public clinics, where the same brush may be used for different patients, when it has passed through a solution of nitrate of silver. I instance this fact, not to encourage economy THE CONJUNCTIVA. 327 in the use of brushes, but as a point worth knowing. Every patient needing an application to his lids, should have his own brush; and purulent cases should be most vigorously quarantined from com- munication in any manner with other patients. The symptoms are at the outset hyperaemia of the ocular con- junctiva, swelling and closure of the lids, and a thin and ichorous discharge; there will be smarting and burning, which soon rises to pain both in and around the eye, oedematous infiltration increases until the lids become hard, tense, and shine with a dusky red, and the upper overhangs the lower. A similar infiltration takes place beneath the ocular conjunctiva, lifting it from the globe and making it mount over the edge of the cornea (chemosis). The secretion in a little time becomes more and more purulent and soon seems wholly of this quality. The temperature of the parts is elevated, and the whole picture is that of an excessively severe inflammatory process. If the lids can be separated, the conjunctiva is not only red, but is often speckled with hemorrhages; it is covered with pus, and especially on the palpebral surface during the early period, there will also often be a layer of plastic exudation, which will come off in rolls or may adhere rather closely. When wiped away the surface beneath it bleeds. It is oftentimes impossible to sepa- rate the lids enough to view the eye properly, and the attempt gives so much pain that the patient involuntarily and strenuously resists it. The great danger is mischief to the cornea. This may come during the full activity of the disease or not until we begin to felic- itate ourselves that the climax of the attack has passed. There may be a variety of ways in its manifestation. Either the whole surface may have a uniform opacity of varying density, or this may appear at the centre or periphery. Ulceration may occur in company with it or soon follow it, or may be the first invasion. A furrow at the margin of the cornea, beneath the overhanging che- mosis, may completely or partially encircle it, and it may eat through the cornea in a very few days. Ulceration at the centre, or at any point, is equally prone to occur. The degree of corneal mischief can never be predicted. It is the product of three factors, namely, the pressure of the swollen tissues, the corrosive action of the secretion, including the invasion of the gonococci, and direct con- tinuity of inflammation to the substance of the cornea. It is also favored by unhealthy constitutional conditions, and by bad hygienic surroundings. It is impossible to assign to each factor its exact measure of influence, or to assert that a peculiar lesion of the cor- nea must be attributed to predominance of one or the other of them; in most cases, all concur in the disastrous effect. The culmination of the active symptoms commonly arrives 328 DISEASES OF THE EYE. within ten days, and the duration of the disease is from four to twelve weeks. The final result upon vision, in case the whole cor- nea is not destroyed or the eye escapes suppuration, is apt to be better than would seem possible during the severity of the symp- toms. So much of the cornea as may remain will become far more transparent and serviceable than may seem at all likely. Treatment.—From the beginning active measures must be adopted, and the patient should go to bed. In robust subjects, or with intense initial swelling or pain, four to six leeches may be put upon the temple. Bits of muslin taken from iced water, or from a block of ice, should be kept upon the eye constantly, and changed every minute or two as they grow warm. In some cases a bit of ice, wrapped in muslin, may be held upon the eye if its weight can be endured. Continuous cold, to the degree which can be tolerated, is the rule. Absolute cleanliness of the inside of the lids is equally imperative. To effect it, the lids must be drawn apart and the secretion removed by a soft camel's-hair pencil inserted between them, or by dropping an antiseptic solution upon the eye from a small sponge, or by injecting such a solution with a small bulb syringe. Some one of these methods may be chosen, according to convenience. This process will be repeated every five or fifteen minutes during the days and nights of active secretion, and at longer intervals as the discharge lessens. The antiseptic fluid may be sol. corrosive sublimate, 1 to 3,000-10,000, or boric acid 4$, or of chlorinated water 10$. It is sometimes well to use an elevator in separating the lids, but by sensitive persons this will not be al- lowed, and extreme delicacy is needful in all manipulations, espe- cially when ulceration has appeared upon the cornea. In certain cases in which the discharge is not thick and creamy, but ichorous, gruel-like, and thin, and in which the attack is moderate in severity, nothing but this constant cleansing, by antiseptic lotions and the iced water, are needful; no caustic need be applied. I have seen a remarkably good recovery of a case like this, in a young man who acquired the disease from gleet. Mr. Grossmann of Manchester has recommended the ointment of yellow oxide of mercury in vaseline. Dr. Wilson of Bridgeport reported success by a mixture of boric acid and vaseline. Experience has shown that putting vaseline hourly between the lids is an important aid in getting rid of secre- tion and preserving the corneal epithelium. This practice is now generally adopted in New York. The fidelity and thoroughness of the cleansing by night and day have the greatest influence in the fight for preservation of the eye. Should the cornea become in- vaded, a solution of sulphate of atropia, gr. ij. ad § i., should be in- stilled every three to six hours. It will be seen that, to perform this laborious nursing, not less than two attendants, both strong and faithful, are necessary, THE CONJUNCTIVA. 329 Another indication is to be borne in mind in severe cases, viz.: the relief of pressure by incising the swollen tissues and un- loading the vessels. Mr. Tyrrell laid stress on scarification of the chemotic conjunctiva, the infiltration does not flow away however deep the cuts, because it is of a plastic and coagulable quality, but the depletion is of use, and the incision may be re- peated. Canthotomy freely done unloads the vessels and lessens the pressure of the lids by weakening the orbicularis and giving room for the infiltration to spread. I consider this proceeding in- dispensable when great swelling of the lids exists, and do it with little swelling if the cornea be threatened. It may be need- ful to again snip the tissues with scissors in the site of the cut, after a week or more, because healing quickly takes place, and conditions of partial strangulation by the lids may be reproduced. In resorting to such proceedings, a surgeon will require to act with discretion as well as boldness, appreciating the significance of the symptoms, the danger to the eye, and the general health of the patient. As against the propriety of incisions, the partial inter- ruption of the process of cleansing is to be considered; but this need not be wholly suspended; its method may be so modified that the lid need not be greatly disturbed for the next twenty-four hours. Mr. George Critehett once resorted to medial vertical division of the upper lid in an infant and thereby as he thought saved the eye. The writer be- lieves that such a proceeding might judiciously be sometimes done in adults, because the disastrous results of the disease are deplorably frequent and the deformity to the lid could be easily repaired. The advantage is obvious both by relief of pressure and in facility of cleansing. Exposure of the cor- nea is the one thing to be guarded against. Next, we have to consider the use of nitrate of silver. It will have no place during the period of invasion, and of copious thin, gruel-like, puriform secretion. But when the secretion becomes creamy and distinctly purulent, and the conjunctiva velvety, a solution gr. v. vel x. ad 3 i., may be tried on the everted lids. The longer the brush is held in contact with the surface, the greater is its effect, and this may not be small. Pain will ensue for an hour, or longer; for a time the secretion is suspended, or becomes watery, and if after twenty-four hours the swelling is less, and the secretion not so copious, the remedy has been well chosen and may be repeated. It must be remembered that the first application is tentative, and tG be carefully watched in its effects, especially on the cornea. The 2$ solution is generally to be preferred (gr. x. ad 3 i.). Formerly much stronger solutions were in vogue, but stronger than 4$ they are not to be commended. Thorough contact with all of the con- junctiva is very difficult even when the lids can be fully everted, 330 DISEASES OF THE EYE. but an effort must be made to effect it by thrusting the brush up to the fornix. The solution is by some dropped upon the ocular conjunctiva, but care must be taken to avoid the cornea; it may be dropped in three times daily when chemosis is extreme. The ap- plication of caustic to the lids will usually be made once in twelve or twenty-four hours, seldom oftener and frequently but once a day. The recurrence of the purulent secretion is the signal for repetition.' It is at this point that the good judgment of the physician is tested. That copious use of vaseline is a valuable co- adjutor is indubitable. No remedy has such general acceptance in this disease as nitrate of silver. Recently peroxide of hydrogen in watery solution con- taining 3$ by weight has been proposed by Landolt as of value as an antiseptic. It acts by the rapidity with which it liberates oxy- gen, and it has the effect of abating the quantity of pus, but exerts no special control over the inflammation. It must be kept at a tem- perature below 60° F., and in a bottle tightly corked. The tissues remain swollen and soggy and the cornea is no less liable to be in- jured. It does not supersede the caustic It is not irritating pro- vided in its preparation it is free from sulphuric acid. Iodoform has been dusted into the eyes, but iced water and other remedies have at the same time been employed, and we are not authorized to assign special value to it. It may do well for cases of mild type and with persons who will not submit to confinement and constant treatment. The powder must be extremely fine and be dusted freely over the everted lids. When corneal ulceration exists it may be used, but the remedy is less in favor now than it was. Recent authors, Heyl, Freyer, have substituted hot water, of a tempera- ture as high as 112° to 120° Fahrenheit, for iced water and reported useful results. Heyl uses it for one-half an hour three times daily, while Freyer employs it from six to eight hours. Heyl confesses want of success in dealing with adult cases, and his experience has chiefly been among infants. With them the disease, if attacked early enough, is seldom destructive to vision, and whether by hot water its duration is briefer than by iced applications remains to be corroborated. Freyer's claim of better success in the adult cases also awaits corroboration. Very recently corrosive sublimate has been again brought into use and in two different methods. The first is applications of solutions 1 to 500 to the everted lids with such frequency as will hold the purulent secretion in check. The strength of the solution may even be increased if the physician is con- stantly at hand and does the work himself; this is feasible only in hospital practice. Great pain is produced, and all usual precautions of cleanliness and cold lotions are maintained. Another method is to scarify the con- junctiva both palpebral and ocular by incisions 2 or 3 mm. apart and brush it moderately with a solution 1 to 1,000. An anaesthetic must be given. A THE CONJUNCTIVA. 331 common tooth-brush is used, and canthotomy may be done. A remarkable abatement of secretion takes place, although the lids may swell. The same proceeding may have to be repeated at intervals of three days for two or three occasions. The germicidal value of the remedy suggests the treatment. I have employed it in five cases with good effect, and purpose to use it further. An unpleasant complication is the ultimate production of more or less ex- tensive and irregular adhesions between the lids and the globe. The cases were patients of the infirmary who could not be taken under hospital care, and for conditions so unfavorable I was glad to find an effective treatment, although painful and attended by the drawbacks mentioned. In no instance was serious damage done to the cornea. The customary auxiliary proceed- ings were insisted on. The depth to which the gonococcus penetrates the tissues and the amount of oedema determines the need of scarifications and the method and vigor of the brushing. When infiltration of the cornea appears, a solution of atropia should be used and especially for central ulcerations. It is to be remembered that iritis is very liable to occur and hence atropia has an important indication in all corneal complications. Should there be a marginal ulcer, a weak solution of sulphate of eserine, gr. ss.-i. ad § i., may be used twice daily. But it does not exclude the intercurrent use of atropia. If strong eserine solutions are used, they may provoke pupillary adhesions. In many cases we are not allowed to debate the propriety of this treatment because of the rapid advance of ulceration. If it threaten to perforate, we may perform paracentesis—for actual prolapsus iridis we are to do nothing with the iris: excision does harm. While in simple corneal ulcerations without blennorrhcea, we derive advantage from the actual cautery such is not the fact in the situation now considered. The tentative use of very hot water, 110° to 120° F., may be sug- gested on general principles because of the perilous predicament, but the writer has no experience on the point. The issue of an attack may be in perfect restoration of the con- junctiva to its normal texture, in case it were healthy before, but it not seldom passes through a period of papillary hypertrophy (granulations) which may continue for weeks. The case may be under treatment for this condition long after the ocular conjunctiva has recovered its normal state, and at this stage, sulphate of cop- per crystal, tannin and glycerin, 3 i. ad 3 i. or stronger, will be the most useful applications. In the event of the cornea being dam- aged, all eventualities are possible, between a slight degree of opac- ity, almost amounting to transparency on the one hand, and sta- phyloma corneae, or atrophy of the globe, on the other. A partial staphyloma, or anterior synechia, for which an artificial pupil may be practicable, is exceedingly common. It is of course possible that both eyes may be lost, but the right is the one most often affected; and it is common, when a second eye is attacked, for it to be less 332 DISEASES OF THE EYE. severely inflamed than the first. The reason is, because the secre- tions are less noxious during the decline of the inflammation. For this reason, the pus of a florid urethritis will cause much more severe inflammation than that from the stage of gleet. The fatality to sight of this disease is great, and is set down by Klein as follows: Out of 40 eyes, 16 became totally blind, 9 retained some vision, and 5 had useful vision, or could obtain it by operation: in 30 the cornea was involved, while in only 10 did it escape. That is, corneal trouble occurred in three-fourths of the eyes, while 40$ be- came blind. The protection of the fellow-eye, in case it be intact, is of the utmost importance, and my experience has been that the endeavor to seal it hermetically by a bandage or plasters, is ineffectual. It cannot be carried out rigorously, because of the wretchedness which it inflicts in making the patient for the time wholly helpless, and because of the excoriation of the skin of the cheeks and lid, and of the impossibility of preventing the patient from slipping off the covering during the night, and unwittingly exposing himself to contagion by his soiled fingers or accidental communication from the other eye. In fact, the need of handling the eye to change the dressings, which should be done twice daily, involves more exposure than to warn the patient and attendants of the need of the utmost caution, and to insist that the patient sleep, lying on his back, or on the side of the affected eye. A device, whose authorship belongs to Dr. Buffer, of Montreal, has answered well, viz., to cover the sound eye with a watch-glass, attached by means of rubber plas- ter. It need not be removed oftener than once in several days, as secretion may demand. 4. Plastic Conjunctivitis, viz.: a. croupous and b. diphther- itic.—Under the description of purulent conjunctivitis, we have mentioned that sometimes the secretion is to a degree plastic either forming shreds, or adhering to the mucous surface. No special significance is to be attached to this fact, but cases some- times arise where the plastic quality of the secretion is a distinctive peculiarity, predominating over all other features of the case, and, therefore they deserve special mention. Various grades of this quality appear, and if we find that the layer of false membrane can be easily rubbed from the conjunctiva, there may be no need of regarding the case as differing essentially from a blennorrhoea because it will soon exhibit the features of the latter by transfor- mation of the plastic substance into ordinary purulent secretion. On the other hand, we meet cases in which a plastic exudation is the dominant fact. It will appear in greater or less degree and while the moderate cases differ so widely from the most severe as THE CONJUNCTIVA. 333 to warrant separate designations for each, we also meet interme- diate degrees of severity which it is difficult to bring under an exact classification. Some authors insist upon describing croupous and diphtheritic conjunctivitis as separate diseases. In the former (croupous) the eyelids alone are attacked, the exudation is moder- ately adherent because superficial; by rather severe friction with a rag it can be rubbed off and exposes a bleeding surface. The deposit may be in patches or spread over the whole surface. The general reaction is moderate, the lids not much swollen, the ocular conjunctiva red and somewhat oedematous, the cornea seldom in- volved either in opacity or ulceration. On the other hand, diph- theritic conjunctivitis is described as a condition in which both the palpebral and ocular conjunctiva is covered by plastic exudation, which is dense and gray, penetrates deeply into the tissue, involves the whole mucous membrane, and in the lids attacks so great a depth of tissue as to make them hard, stiff, and brawny. The material cannot be wiped away and the structures are deprived of blood by the intrusion of the plastic substance. The cornea is very liable to ulceration or necrosis. There will be fever and general prostration. The first distinct portrayal of this condition was in one of the earlier papers of Von Graefe: and it was limned with a master-hand. There is no doubt that under the above description of croupous conjunctivitis many cases may be ranged with correctness and that the disease is purely local. But if we attempt to be thus precise in our designations we fall into error. I have treated a case in which the plastic exudation was confined to the lids, but was not superficial, it was incorporated with the deep texture and never could be wiped away; and finally it disappeared by absorption or simple melting away, as I have seen similar material behave when exuded upon the tonsils and fauces in a fatal case of diphtheria. Again Nettle- ship describes (St. Thomas' Hosp. Reports, Vol. XIV., 1886) two cases of fatal diphtheria beginning in one instance on the conjunc- tiva of one eye and spreading to the nose, throat, and opposite eye, and in which both lids of the eye first affected, were lined with a moderately adherent membrane, but the substance of the lids was not infiltrated nor swollen; the ocular conjunctiva was infiltrated and the cornea was represented by a thick, white, soft slough. The fauces were covered with membrane. The other eye became af- fected, but the hard, brawny, rigid, and bloodless condition said to be typical of diphtheritic conjunctivitis was never present. Yet this case, by its complications and fatal issue, was unquestionably one of diphtheria and the ocular disease was diphtheritic conjunctivitis. Mr. Nettleship also reports another case of " muco-purulent oph- thalmia of the right eye" with membrane on the lower lid, both its 334 DISEASES OF THE EYE. mucous and cutaneous surfaces, also on the free border of the upper lid, but not on its palpebral surface. The other eye was normal. The pillars of the fauces on both sides, the tonsils, uvula, and soft palate were covered with a thick, gray, ashy membrane; the glands about the jaw on both sides were enlarged. This was of course diphtheria, and the eye considerably impaired; the other eye re- mained free, and on the tenth day the child died. It seems more logical to speak of such cases in a general way as plastic or diphtheritic conjunctivitis, and not to expose ourselves, by a rigid definition, to a false description of a certain number. We may meet with all the types which have been referred to, and we may choose to call the lighter forms croupous, but it would be less erroneous to style them mild degrees of plastic conjunctivitis, and we may call the graver forms intense degrees of plastic con- junctivitis, or when constitutional symptoms appear we may cor- rectly call the cases diphtheritic irrespective of the depth or extent of the plastic infiltration of the conjunctiva. It may be proper to quote from Flint's " Practice of Medicine," 1881, p. 38, a passage which describes the pathological anatomy and which will also serve to explain the cause of the various forms of the disease we are discussing. He says: " The terms croupous and diphtheritic are applied to fibrinous exudations upon mucous membranes. Unlike the inflammations of serous membranes, the ordinary inflammations of mucous membranes are not accompanied by a fibrous exudation. The term catarrhal is sometimes applied to those simple inflammations of mucous membranes characterized by an exudation of serum, mucus, and some pus-cells. According to the careful investigations of Weigert, fibrin is present in the inflammations of mucous membranes only when the epithelial covering is partly or wholly destroyed. The epithelium may be destroyed from various causes, among the most important of which is coagulation necrosis. The necrosis may extend deeper than the epithelium into the subjacent tissues. When only the epithelium is destroyed, the fibrinous exudation lies upon the membrana propria of the mucous mem- brane, from which it can readily be stripped off without loss of substance. This form of exudation is called croupous. When the primary necrosis in- volves the tissue-cells as well as the epithelium, the fibrinous exudation ex- tends from the surface into the tissue of the mucous membrane, and cannot be removed without loss of substance. This second form of exudation is de- nominated diphtheritic. When the fibrinous exudation adheres closely to the mucous membrane without really infiltrating it, it is called pseudo- diphtheritic. It is to be observed that croupous and diphtheritic exudations require destruction of the epithelium only in one place, and that they may extend themselves over the surface of the surrounding intact epithelium. The fibrin in croupous and diphtheritic inflammations is derived partly from the blood, partly from metamorphosis of the epithelial and other cells, and perhaps, partly from fibrinoid degeneration of the intercellular substance (Neumann)." The remark made in this quotation " that croupous and diph- theritic exudations require destruction of the epithelium only in THE CONJUNCTIVA. 335 one place and that they may extend themselves over the surface of the surrounding intact epithelium " was emphatically exempli- fied in a patient whom I saw with Dr. R. H. Derby; a young child with a thick coating of plastic exudation over the upper lid as the special feature of a severe inflammatory condition. It could be easily pulled off as a whole, and displayed at one point a mass of sprouting granulations as large as a pea where the mucous mem- brane seemed to be perforated. Observation for successive days proved this spot to be the focus whence the exudation extended. When by cauterization these granulations were destroyed, the ten- dency to diffuse plastic exudation speedily disappeared. The case continued for several weeks. It must be added that cases are recorded in which a film of plastic material continued to form and be thrown off for many months, not only upon the palpebral, but on the contiguous ocular conjunctiva, while the reaction was moderate both in swelling and other inflammatory features, and finally the eye recovered. In other words, plastic conjunctivitis appears rarely as a chronic af- fection. Cases which persisted as long as five months are given by Nettleship, St. Thomas' Hospital Reports, Vol. X., 1880, and by Critchett and Juler, Trans. Oph. Soc of United Kingdom, Vol. III., p. 1, 1883, with colored plate. Sometimes one only, but usually both eyes are affected. While usually spontaneous, it may occur after operations upon the eye, as happened once in my experience in a boy ten years of age oper- ated upon for strabismus; the dense gray plastic infiltration ex- tended from the wounds over the ocular and then over the palpe- bral surfaces, with the typical characteristics of stiff and bloodless structures. It sometimes occurs after the exanthemata, measles, or scarlet fever, and broncho-pneumonia; it may go up from the throat and nose: chronic inflammatory conditions of the conjunctiva pre- dispose to it. Epidemics may occur. At its outset it may be ac- companied by severe swelling and great redness of the lids, almost erysipelatous, but ordinarily the swelling is moderate and the dis- charge slight. In certain instances, which seldom occur, the lids are firm, stiff, hard, difficult to evert because of the depth of the infiltration. Their temperature is increased, and handling produces much pain; it ma}r be impossible to evert them. The contrast between the abundant plastic infiltration and the absence of secretion in these severe cases is remarkable. The cornea is liable to opacity at an early period, and may easily succumb either by ulceration or by diffused infiltration. When cut into, the lid is gray, lardaceous, and little disposed to bleed. The tissues are filled with micro- organisms. Not infrequently diphtheritic patches are found in the 336 DISEASES OF THE EYE. nostrils. The period of infiltration lasts from six to twelve days, when the membrane begins to be dissolved and comes off or is ab- sorbed; reddish streaks and patches appear'in the white deposit, the lids become softer, the conjunctival tissue is more succu- lent and velvety, showing a papillary outgrowth, and a discharge, which gradually becomes purulent, sets in; after a time the case takes on the aspect of an ordinary blennorrhcea. During the process of healing of severe cases, an abundance of cicatricial tissue is de- veloped, giving rise to atrophy and shrinking of the conjunctiva. The prognosis is in these cases extremely grave, and life itself is sometimes at issue. It must be added to the above description that a membranous exudation may form on the cutaneous surface and edges of the lids, and the conjunctiva present simply a blennOrrhoeal condition. Even sloughing of the skin has been observed (Nettleship) and there may also be ulcerations and exudations or herpetic eruptions on the cheeks about the nostrils and lips, and perhaps exudation in the throat. The health of the patient and his surroundings are of great im- portance in contending with this malady. Treatment.—For the milder cases cleanliness and not very cold lotions are sufficient; boric-acid solution may be employed, and the disease will readily yield within a few7 days. As the tendency to production of plastic membranes abates, a weak nitrate of silver solution, 2 or 5 grs. ad 3 i., may be employed once in twenty-four hours. There are, however, exceptional cases, of which within a year I have seen one, where the disease is more obstinate. The exudation, though confined to the lids, penetrates the membrane, cannot be wiped away, and persists for weeks; at the same time some ulcer- ation may take place at the edge of the cornea. In the instance in my mind, applications of cold with cleanliness and mild remedies had no controlling influence. The best result was at length ob- tained when a solution of corrosive sublimate, 1 to 2,000, was pen- cilled over the everted lid several times a day, and a solution, 1 to 5,000, used as an external wash. Antiseptic and germicidal substances are obviously indicated. In selecting them and their degree of concentration we must be guided by the intensity of the process and its stage. The very grave cases are fortunately rare, and in them the dense infiltration imperils the vitality of the tissues, threatening gangrene. If this confronts us we may use hot instead of cold lotions, and resort to antiseptics cautiously. A trial of corrosive sublimate, 1 to 1,000, may be made when some secretion appears, and if not too greatly re- sented may be repeated, carefully watching its effects. In fact the treatment must be tentative and the case frequently inspected. THE CONJUNCTIVA. 337 If swelling be great we will use cold, even iced lotions, and employ mild antiseptics cautiously to remove secretion. The germicidal use of corrosive sublimate, meaning in strength 1 to 500 or 1 to 2,000, requires caution and judgment. Its antiseptic use 1 to 5,000 will be persistent. One may employ as antiseptics aqua chlorinat., sol. sodae chlorinat. (Labarraque), 1 to 5, sol. potass, permanganat 2r;. Finely powdered iodoform, dusted into the eye, or mixed with vase- line, 3 i. ad 3 i., is to be suggested. If swelling be so great as to make canthotomy advisable, the cut surfaces will be invaded by the exudation. Wolfring recom- mended the ung. hydrarg. oxid. flav. with vaseline 3$ rubbed oh the mucous surface once or twice daily with energy, but its value has not been sustained, although approved by Schmidt-Rimpler, 1885. When the plastic material begins to disappear and a red and succulent surface emerges, the nitrate of silver will find place, but never until this stage. Its utility is precisely the same as in cases of purulent inflammation, and the rules for its employment will be the same. As the disease abates, the cold lotions and the cleansing will be less frequent. Leeches and depressing remedies are out of place. Constitutional treatment may not in many cases be neglected. Foremost is the necessity of sustaining the nutritive power by careful feeding, by iron in full doses, by quinine, and perhaps by stimulants. Milk will be largely employed, and all the measures called for by other complications, whether in the nostrils or the throat, on the face or in the chest, will be resorted to. By v. Graefe and by some of his followers mercurials have been given, but they are not to be relied upon. The disease may be very serious and the great danger is to the cornea, while in certain types the conjunctiva undergoes atrophy, sometimes causing broad adhesions or fraena at the retro-tarsal folds, and may eventuate in entropium or trichiasis. The risk to life has been referred to, but this is not often met with. The cornea in some instances suddenly and totally breaks down with yellow infiltration, while usually the damage comes by ulceration and per- foration beginning at a particular spot. Graefe, out of 40, lost 9 eyes; Hirschfeld, out of 94, lost 34 eyes; Jacobson, out of 22, lost 5 eyes. The fatality in epidemics is apt to be most severe. 5. Granular Conjunctivitis—Trachoma.—Under this name is grouped a variety of conditions apparently quite dissimilar, whose chief characteristic is hypertrophy of tissue, and which has received its name from the presence of certain granules or follicles which under one form or another are considered essential to it. It may or may not be attended by acute inflammation. The name tra- 338 DISEASES OF THE EYE. choma was popularized in ophthalmology by Stellwag, who called attention to the granules as marking the disease, and they are often called trachoma granules, but have nothing in common with the granulations of a healing wound. In many cases of granular con- junctivitis they are not recognizable to the naked eye because im- bedded in the tissue; in some cases they do not exist, in some cases they are few and hard, in other cases they are most exuberant and very soft. We find them as semi-transparent, seed-like bodies, compared to grains of boiled sago or the spawn of frogs; they may, in old cases, be dull red and in hard, flattened masses. They often appear in a ridge along the orbital edge of the tarsus as a semi-opaque infiltration, and their seat of election is the fornix of the upper lid and not much less frequently of the lower lid. In these localities they exhibit clefts and prominences like a cauli- flower, owing to the laxity of the tissue. Besides these granules we have more or less hypertrophy of tis- sue, which may appear as fine or conspicuous papillary outgrowth; the membrane is deep red, usually rough, sometimes is smooth, and occasionally is enormously thickened. After long continuance fibrillae of connective tissue appear, and in the end it supersedes all other textures, bringing about atrophy and various degenerations. Under certain phases there is secretion, either watery or mucoidal or puriform—in most cases, and these the chronic ones, there is little or no secretion. While of necessity a source of discomfort, the chief misery and mischief are through the lesions of the cornea. This becomes hazy, vascularized, ulcerated, densely opaque, sclerosed, perhaps perfora- ted and staphylomatous. The vascular haziness is called pannus and may be in most various degrees of density, called p. tenuis (thin), or p. crassus (fleshy). The upper portion of the cornea may alone be affected, the whole may be implicated. The pannus may occur during the period of hypertrophy; its worst forms are found in the last sad stage of conjunctival atrophy. The disease affects the upper lid more than the lower; very rarely does it attack the ocular conjunctiva, save in the form of follicular trachoma, and then by continuity from the fornix. It is chronic in its duration, liable to intercurrent inflammations, affects chiefly those in poverty or living in unhealthy conditions; is a pest in asylums, orphanages, barracks, and poor-houses; is found among children (seldom in infants) and adults of all ages; in later life is seldom begun, but merely continued. It has general geographical limitations, in the sense that in certain countries it is far more severe and prevalent than in others. For example, in Ireland Holland, Belgium, Turkey, and Egypt it is the curse of the common people. In Russia it abounds, in middle Germany it prevails less THE CONJUNCTIVA. 339 than in southern Germany and Austria. In the United States it affects the dwellers in tenement-houses, and goes with unhygienic conditions in large cities. It prevails in the Western prairies and is found scattered widely over the country. A high altitude is un- favorable to its production, as proven in Switzerland. See Chibret.1 The negrcr race are said to be exempt (Burnett), although mulat- toes of every grade are its victims. It occurs among the Western Indians. Most important is the favoring influence of the so-called lymphatic (scrofulous) temperament. On this point sufficient stress has not until lately been laid, although clinicians have always rec- ognized the fact in practice. This accounts for its appearance oc- casionally among the wealthy and well-cared-for, and it is not less obstinate among them than their poorer fellow-creatures. See True2 For its dispersion another cause must be assigned, viz., a degree of contagiousness. On this point careful discrimination is requisite. Those phases accompanied by secretion are undoubtedly contagious, and in the degree of its copiousness. For example, the so-called Egyptian ophthalmia, which is a mixed condition; the dis- ease as found in public institutions, educational and eleemosynary; the so-called acute trachoma, some cases of follicular trachoma— all are attended by muco-purulent or other secretion, and in all a great variety of microbes are to be found. The means of contagion are in Egypt flies and other unsavory media (Howe), use of towels and toilet articles in common, washing in the same water, and the innumerable modes of conveying filth practised by filthy people. The contagium may adhere to the walls and floors of the places where the patients live (Cohn3), it being assumed that these places are prone to be dirty and the inmates will always be more or less crowded. Accidental conveyance to the eye of a cleanly and healthy person by the secretion is of course possible. On the other hand, the large proportion of chronic cases, of whatever variety, do not communicate the disease to others, because the quantity of secretion is a minimum. A single person in a cleanly household does not spread the disease, and if there be several pa- tients its extension may be prevented by strict care and attention to hygiene. It has been stated that numerous micro-organisms are found in the secretion, and they are of many varieties, sometimes includ- ing even the gonococcus, while the usual pus-producing organisms and the streptococcus can always be detected. This fact explains easily the rapid and insidious extension of the disease in suitable localities and among susceptible persons, and does away with the 1 Annales d'Oculistique, t. cv., Jan. Fev., 1891, p. 22. 8 Annales d'Oculistique, t. cvi., Aout, 1801, p. 81. s Lehrbuch der Hygiene des Auges, p. 139, 1891. 340 DISEASES OF THE EYE. mystery which has seemed to conceal its mode of propagation, be- cause the air as well as numerous recognizable agencies become the ready means of transmission. Yet another supposed possibility of contagion is to be mentioned, viz., a micro-organism peculiar to and residing in the follicles of trachoma, a coccus first described by Sattler1 in 1882, and by Michel,21885. It is a diplococcus smaller than the gonococcus and appears in groups like sarcinae. Some observers have confirmed this discovery, while not a few deny that its culture can give rise to trachoma. Contrary opinions yet pre- vail, but the belief in the important influence of micro-organisms is universal, because antiseptic treatment has become so efficient and widespread. We have now given an account of the disease in its general features, and we must set forth its subdivisions. We designate them from a clinical standpoint, and in so doing point out the con- spicuous features of each variety, admitting that sharp divisions are impossible because one type shades into another, and this is true not only in external appearance, but in course of development, and in pathological anatomy. We may speak of: 1, Papillary trachoma; 2, Acute trachoma; 3, Follicular conjunctivitis, fol- licular trachoma, foil iculo sis; 4, Chronic trachoma; 5, Sequelce. (1) Papillary trachoma or chronic blenorrhcea presents itself under two phases. The first is a condition of velvety hypertrophy of the palpebral conjunctiva with moderate injection and no se- cretion, and not thick enough to conceal entirely the normal yellow tint of the tarsus. It is the outcome of mild but chronic conjuncti- vitis; no granules are ever to be found; the papillae are very fine and short. The second phase exhibits greater thickening, resem- bling plush rather than closely shaven velvet—the papillae com- pletely conceal the color of the tarsus, they stand thick and high, may present clefts and prominences; the whole tarsal surface and the fornices are involved; the semi-lunar fold and the ocular con- junctiva are injected and more or less swollen. There is constant, perhaps copious secretion with photophobia, erosions of the corneal epithelium, vascularity at the limbus. The condition follows acute, usually purulent conjunctivitis, and has been strenuously separated from " true trachoma " because the fibrous degeneration rarely occurs. Nevertheless the follicles are to be found imbedded in the tissue, although not visible during the distinctive papillary period and perhaps never seen by the physician. The cornea may be superficially hazy, but eventually clears up if proper treatment is used. (2) Acute trachoma, a condition in which there is great swelling 1 Archives of Ophth., xv., 452, 1886. 2 Bericht der Congress Heidelberg, 1882. THE CONJUNCTIVA. 341 of the whole thickness of the lids, great hypertrophy of the con- junctiva, which comes on rapidly, accompanied by severe pain, heat, injection of the ocular conjunctiva and discharge of an almost purely watery quality. E version of the lids is difficult, and the palpe- bral conjunctiva has a dotted look, is intensely red and shiny, and does not exhibit special papillary prominences or trachoma gran- ules. After the subsidence of the acute symptoms, viz., in from one to three weeks, trachoma granules and moderate papillary hypertrophy will be seen. This condition is not very liable to cica- tricial degeneration, and the cornea usually escapes. It is some- times evidently dependent upon an acute exacerbation of hyper- trophic nasal catarrh. It may begin without previous conscious trouble, it may come as an exacerbation of chronic trachoma, es- pecially in lymphatic subjects. It passes into the chronic type as the acute symptoms decline. (3) Follicular Trachoma—Folliculosis.—The subject is usually young, apt to be of lymphatic temperament. For some time has been unable to use eyes with comfort, either one or both. The lids droop, perhaps seem swollen; no redness of ocular conjunctiva, but it is moist. There is moderate sticky secretion. The patient shuns the light, is much irritated by wind and dust, but has no pain; cornea clear. The lids are easily everted, and if pains be taken to unfold the fornices (see p. 310) a most striking picture is sometimes displayed. We find the tarsal surfaces dotted with small seedlike bodies, semi-transparent, perhaps as large as hemp-seeds; they lie in and upon the pale pinkish-gray membrane, and as we pass to the folds of reflection they increase greatly, perhaps enormously in number, crowding forward in great, succulent, gelatinous-looking masses. The conjunctiva at the culs-de-sac is pale, yellowish-pink, but thrown into transverse ridges. The conditions vary in inten- sity, but it is not rare to meet a case of prodigious redundancy of follicular masses of which no serious complaint had been made and accompanied by no important symptoms. The condition has de- veloped slowly, is slow to disappear except by surgical treatment. It may pass over into the usual phase of chronic trachoma with fibrous tissue formation (Raehlmann,1 Reich2), but this issue is not frequent; nevertheless, the attested fact proves the cousinship of the disease. The cornea is not affected unless the case be neglected. It yields readily to proper treatment. By some writers this con- dition is regarded as standing apart from trachoma. The evidence of recent investigations, clinical and pathological, is in favor of its kinship, although it is far less serious than chronic trachoma. 1 Graefe's Archiv, xxix., 2, 73, 1882; also, Wiener med. Wochenschrift, 41, 1890. 2 Nagel's Jahresbericht, p. 283, 1S89. 342 DISEASES OF THE EYE. (4) Chronic or Mixed Trachoma.—We meet with extremely different degrees of this condition—the characteristic of all being the presence in varying quantities at some period of their duration of the trachoma follicles, or, as it is also called, of lymphoid infil- tration. We classify the different degrees into the following: (a) Isolated deposits of granules with little or no thickening of the conjunctiva. These are found almost exclusively in the folds of reflection; they may be single or in groups. They cause slight or sometimes no irritation and no secretion. Frequently no history of either previous or present inflammation can be elicited. Yet it may have occurred. (b) Lymphoid infiltration disseminated in granules, or forming a ridge at the orbital margin of the tarsus, and sometimes pre- senting also thick deposits in the culs-de-sac and accompanied by thickening and more or less papillary hypertrophy of the con- junctiva. This condition is most pronounced in the upper lid, while the lower may not escape. The ocular conjunctiva is very rarely implicated. There is little secretion, but there may be lachryma- tion; the amount depends on the activity of the attendant inflam- matory action—it may be almost wanting. There will be photo- phobia, and to an intense degree, if the cornea have become vascular. Serious implication of the cornea is the tendency of the lesion. Occasionally lymphoid infiltration occurs in its substance. The diversified appearances of the palpebral conjunctiva cannot be fully described. One must imagine a very great variety of pos- sible pictures, both in quantity and distribution of the infiltration. After a certain duration, with or without abatement of thickening grayish lines of fibrous tissue make their appearance; they form a mesh, and patches, and sometimes hard masses of lymphoid sub- stance are left projecting above intervening spaces of dense and shrunken conjunctiva. The shrinking after development of fibrous tissue sometimes affects the membrane uniformly and leaves a glazed, red surface or a patchy piebald mixture of red and yellow- ish spots, with a concave tarsus which has shrivelled in breadth and length, sometimes reduced to a solid ridge. Meanwhile the folds of reflection have been shortened or possibly obliterated and the conjunctiva may spring out into vertical ridges when the lid is everted. The degenerative process in the final stages reduces the conjunctiva to a dry cuticular membrane, xerosis. Reference has already been made to the possible damage which may be en- tailed upon the cornea, and this feature commands the constant vigilance of the physician. Without dwelling on the desperately bad conditions which are possible, it must be emphasized that hazi- ness of an apparently unimportant degree will sadly reduce vision so that V=-iV may be considered fortunate, while to the naked eye THE CONJUNCTIVA. 343 the corneal tissue is pretty clear. Add to this the depreciation due to change of curve under the softening tendencies of the process and the pressure of the lids, and we find irregularities which defy correction by any glasses. I have recently seen a patient, observed twelve years ago, who requires cylinders — 20.D at oblique axes, and gains vision of 0.2 in one eye and 0.05 in the other. She is now forty-five and dates the lesion to her childhood. She is on the whole fortunate. (c) Still another phase of chronic trachoma is that in which enormous hypertrophy of the palpebral conjunctiva takes place, increasing to a uniform thickness of 5 to 7 mm., as I have often witnessed. There is marked ptosis; eversion is very difficult, for the tissue is hard and brawny; the conjunctiva when exposed is smooth and glazed and very red; there are no granules visible, or they are deeply set and scarcely discernible. I have known such cases looked upon as amyloid or tuberculous, or syphilitic. In fact, a condition called hyaline degeneration of the conjunctiva has been described by Raehlmann and by Kansocki and Vossius.1 It cor- responds very closely to the sketch above given; the pathologi- cal examination does not exclude the possibility of its origin in trachoma. The duration of cases of chronic trachoma may be months and years, perhaps a score of them. Much depends on the attention be- stowed and the wisdom of this attention. Too often patients lose heart and cease trying to get well, or their exigencies compel them to turn to work as soon as matters begin to mend. Hence with increasing trachoma they are liable to relapses and continue to be the patrons of public clinics for long years or decades. Results and Sequelos.—Under this title is included what we or- dinarily mean by prognosis and considerable more. It has already been stated that the milder types may under suitable handling be fully controlled without injury to sight and with no important changes in the conjunctiva. The time required will vary from one to several months. With the softer and more papillomatous vari- eties, provided lymphoid infiltration be not great, and including some cases of true trachoma, the same good result may be achieved, only after a longer fight. I may call attention to a condition which I have never seen mentioned, presented at the very late stage of the cases now considered when most of the hypertrophy has been removed. In the pockets and clefts of the tissue, and to some de- gree imbedded in it, I have sometimes seen white specks of soft molecular substance, suggesting calcareous matter but probably mere detritus of degenerated cells, which keep up troublesome irritation. Under cocaine they may be picked out with a cataract 1 Bericht Ophth. Gesell, Heidelberg, 1889, pp. 108, 114. 344 DISEASES OF THE EYE. needle, and after two or three sittings the irritation has been en- tirely removed. The result of the disease, too often aggravated by heroic treatment, is in severe cases the development in the conjunc- tiva of connective tissue to excessive amount, altering its texture and impairing its secreting functions. The more moderate cases exhibit smooth red patches or lines, or a satiny surface; a higher grade is indicated by fraena and ridges at the folds of reflection; be- yond this stadium the fornix becomes shallow and loses its loose texture in a smooth scar surface, and the last stage is xerosis with posterior symblepharon, and the ocular conjunctiva is reduced to the same cuticular condition, while the cornea has become dry and densely opaque. The connective-tissue growth and resultant contraction enters also into the tarsus, thickening it, bending it inward, and causing the free border to press against the cornea, and on eversion exhibits a furrow along its whole length about 4 or 5 mm. from its edge. The deformity in extreme cases reduces the tarsus to a thick cord which shows a ridge on the exterior surface of the lid and at the same time causes shortening of the palpebral fissure and partial ptosis. Coincident with these changes the numerous glands and follicles of the lid border and tarsus become obstructed, atrophied, obliterated, and in the hair follicles the effect is loss of cilia, trichia- sis, and entropium. It is superfluous to dwell on the mischief wrought upon the cornea, because this is obvious, and it has been already more than once referred to. To prevent it, to mitigate it, to cure it is the great end of our treatment, and our success in this particular is the gauge of the wisdom of our method and the value of our remedies. To shorten the duration of the malady is a great desideratum, but to protect or restore or to save as much sight as possible is of course infinitely more important. Pathological Anatomy.—Much has been written on this topic, and the chief authorities of the last ten years are Raehlmann, Reich, Sattler, Michel, Noiszewski,1 Mutermilch,2 and Reid.3 For more authorities consult Cohn, '•' Hygiene des Auges," p. 780. As to the trachoma coccus, about which something has already been said (see p. 340), the last word is to the effect that the described organ- ism does not have the specific qualities ascribed to it, but that the generative cause of trachoma is a vegetable fungus called micro- sporon trachomatosum s. Jagium, which bears very close analogy to the microsporon furfur, which is the cause of Pityriasis versi- color, and can be seen by a low magnifying power (Noiszewski, 1. c). 1 Centralblatt f. Augenheil, March, 1891. sAnnal. d'Oculistique, Oct., 1891, and May, 1892. 8 Trans. Oph. Soc. United King., x., 1890, p. 57, with plates. THE CONJUNCTIVA. 345 The author declares that he has produced trachoma by pure cul- tures of this fungus in calves and rabbits. Dr. German has traced three Cases of acute trachoma to the poisonous effect of the soil which entered the eyes. The patients were farm laborers and with dirty hands and clothing easily infected themselves (St. Peters- burg med. Wochensch., 1890, 29). Evidently the end of this inves- tigation is not yet. Almost all authorities have bent their attention upon the trachoma follicles and their various appearances as the typical ele- ments of the disease, and have classified cases accordingly. What gives birth to them has not been clearly set forth, and little interest attaches to the shades of difference which follicles from follicular trachoma or from chronic trachoma exhibit. They consist of lym- phoid cells, some within, dead and shrivelled, others without, liv- ing and active, enveloped in a capsule of adenoid tissue, and the mass penetrated by connective tissue, fibres and blood-vessels. The Fig. 132. interior of the glomerule undergoes further degeneration by either hardening or liquefaction, and the capsule is thick or thin accord- ing to age and natural abundance of adenoid tissue. There are also numerous papillae, covered with a thick layer of epithelium in various* stages of proliferation. As they are crowded together, are ulcerated, and adhere more or less perfectly, pockets and clefts and tubules lined by epithelium are produced, and sometimes cystoid cavities are developed. The epithelium easily breaks down and by its metamorphosis gives rise to goblet cells which undergo various regressive changes, and the epithelium may assume a stellate form after its nuclei have become vacuolated. Combine with this the development of connective tissue and the presence of a large amount of adenoid tissue, and the picture as usually given is complete. To the above nothing would be added but for the fact that a paper by Mutermilch (1. c, 1891-92) describes an investigation be- ginning with the earliest phases of conjunctivitis and tracing the 346 DISEASES OF THE EYE. process step by step to the various manifestations of trachoma, and shows how follicles, papillae, epithelial degenerations, fibrous tissue, etc., make their appearance: it shows up the whole panorama. It is a study in pathogenesis as well as in pathology. It were too long to attempt to reproduce this most masterly description even greatly condensed. This may be stated: he traces all the morbid changes to the epithelium and its alterations. Of it he gives a careful description with its superficial mucous corpuscles and its deep layers which send fine processes into the subjacent adenoid tissue, which is a cellular tissue infiltrated by lymphatic cells. De- scribing what transpires with ordinary chronic and acute inflam- mation, he finds the follicles an accidental production dependent on the amount of adenoid substance and the quantity of lymphoid infiltration. He shows how the papillae appear, and the various phases with which we are familiar. But the dominating and novel feature of his exposition is the importance given to the role of the epithelium. He makes this new and striking assertion, that the success of treatment lies in destroying the hyaline lacquer of fused and obsolete cells and in bringing to the surface the living epithe- lium which has been buried beneath effete inflammatory cells and material, and therefore our remedies must not be too harsh. Moreover that pannus appears when the epithelium has been de- stroyed, and corresponds to the degree of its destruction. That the roughness of the palpebral conjunctiva is not its cause, but the absence of living epithelium. Moreover that disappearance of pannus attends the regeneration of healthy epithelium. As to trachoma follicles, he traces in them the effect of a low vitality of constitution with imperfect oxygenation as the predisposing cause why lymphoid cells exuded in inflammatory action cannot main- tain their activity, are soon devitalized and incapable of amoeboid movements, and become grouped into globules by the mechanical influence of the loose adenoid cellular tissue beneath the epithelium. Such enfeebled cells undergo regressive changes and absorption and may quite disappear, but if in large masses they form the be- ginnings of the future follicles. It is inexpedient to go extensively into this fascinating exposition, but the writer finds no essential difference between the follicles of follicular trachoma and those of the more chronic malady. He recognizes that when formed and solidified they become foreign bodies liable to provoke irritation and while themselves the product of an arrested or imperfectly resolved inflammation they may be the exciting cause of persistent or renewed inflammation. He also makes clear how the inflamma- tory products of acute trachoma and of the occasional enormous hypertrophic forms of hyaline material are not anomalous but are in accord with the usual phenomena of inflammation. He makes THE CONJUNCTIVA. 34; it reasonably clear that granular trachoma is no strange exception in pathology, but simply a special appearance due to special local conditions of tissue and interesting because easily observed. Prophylaxis.—A few words are needful as to the measures to protect the healthy from infection, and to put the diseased in the best conditions for recovery. We face this requirement in families, in orphanages, barracks, and places where many persons congre- gate under unfavorable hygienic conditions. It will be remem- bered that the conspicuously dangerous element is the secretion —that this contains numerous pernicious germs, that the air may be foul with them and the walls and clothing may be tainted by them. Hence the rigor of precautionary measures will be in direct ratio to the number of affected persons. In crowded insti- tutions the inmates may have to be scattered, or put into tents, or assigned to other and larger quarters. In schools the piti- ful meagreness of the toilet economy, the few and numerously used wash-basins, the vile roller-towel, and other easily imagined vehicles of filth like rags and handkerchiefs and fingers, et id genus omne, must be thoroughly and peremptorily destroyed, abolished, or purified. Cleanliness, proper air space, sleeping-rooms healthful and well ventilated, good nutrition, out-door life, plenty of water, rea- sonable separation or even isolation are the prime requisites. Next to these come antiseptic lotions, of boric acid, corrosive sublimate, and permanganate of potash (see Cohn, 1. c, p. 139). Treatment.—For the sake of convenience we shall depart from the order observed in describing trachoma and begin with the acute conditions. We consider attacks of primary acute trachoma and the acute aggravations which may take place during chronic trachoma. If there be acute pain and photophobia, more or less swelling, the ocular conjunctiva injected and possibly vascularity with or without ulceration of the cornea, we must employ atropia, cocaine, and cold lotions vigorously. The pupil must be kept dilated; ano- dynes may be required. It is always best to use an antiseptic, and while boric acid has value, corrosive sublimate, 1 to 2,000 to 1 to 5,000, is most worthy of favor (the old lotio flava of sol. corrosive sublimate and lime-water is nowadays fully justified). Scarifications of the conjunctiva may be serviceable. Frequently the aggravated situation depends on the bad (strumous) condition of the patient. The best hygienic surroundings and confinement to bed are necessary. The scratching sensations may be mitigated by free use of vaseline under the lids. If the secretions are copious and watery, medicated applications avail little; so soon as a muco- purulent material appears, sol. nit. arg., gr. v. vel. x. ad § i., may be tried, but with caution. It is always imprudent to employ irri- 348 DISEASES OF THE EYE. tating proceedings during an acute inflammatory stage. It may require from three days to three weeks for this period to pass. It is imperative to keep the pupil dilated, and a 4^ solution of cocaine muriate has useful effects in relieving pain, causing the vessels to shrink, and in reducing tension. Hippel and Sattler recommend sol. corrosive sublimate, 1 to 1,000, applied with a brush to the lid, as soon as any granular prominences appear. It is to be tried with caution, and though painful does prove remarkably useful. If an acute attack supervene during the chronic period, we must abandon the usual remedies of nitrate of silver and sulphate of copper, and endeavor to find out the cause of the outbreak, which may be found in a severe nasal catarrh or in a depreciated state of health. If the former exist, sol. nit. arg., gr. xx. or xl. ad § i., or in less acute conditions chromic acid inside the nares will help us. For the low health, food, change of scene, tonics, cod-liver oil, iron, fresh air, regulated baths will be our reliance. As to the local treat- ment, what has been said above need not be repeated. Papillary trachoma requires moderation in treatment; touch- ing the lids lightly once a day with a crystal of sulphate of copper or alum, with solutions of tannin and glycerin (gr. x.-xxx. ad 3 i.), or with a solution of nitrate of silver (gr. v. ad § L). The patient, if unable to see a physician, may himself make use of an ointment consisting of three grains of sulphate of copper to the ounce of vaseline. As the parts become accustomed to one rem- edy, another must be substituted. Patients may often be pro- vided with astringent washes of alum, of boric acid with sulphate of zinc, and, if no corneal complication exists, of sugar of lead. Powdered boric acid may be dusted on the everted lid. It must be added that for even this class of cases one may make trial of the solutions of corrosive sublimate, 1 to 1,000plus or minus, believing that this potent remedy will do for them what it has so signally done for other cases to be presently related. Follicular Trachoma.—The annoying secretion may be washed away by lotions of boric acid 3$, or of acetate of lead 1%. But there is no reason to lose time on such merely palliative methods. The effective treatment is to destroy and squeeze out the follicles whether they are in isolated masses or in such exuberance as to re- semble the everted rectum of the horse during defecation. Since this method was proposed, I have practised it with much success and to the exclusion of every other proceeding. The patient lies on his back. I use two forceps (see Fig. 133), one in each hand, and hav- ing thoroughly cocainized the surface by a pledget of cotton soaked in 10# solution, evert the lid and hold one end of the tarsus with one forceps and applying the other, pull against the first, thus squeezing and stripping out the granules (see Fig. 134). The for- THE CONJUNCTIVA. 349 ceps enable one to pick up the deepest parts of the membrane, and the line of demarcation between ocular and orbital conjunctiva is usually well marked. I have seen the follicles on the ocular membrane. Bleeding is rather free and must be wiped away with cotton and by drenching with sol. sublimate, 1 to 3,000. All the morbid material can be removed at one sitting. Fig. 133. Some and occasionally smart reaction occurs, requiring cold lotions. This subsides in a few days. For a certain period appli- cations of nitrate of silver, gr. ij.-v. ad 3 i., will be made once a day or every second day and simple lotions employed. Some cases are perfectly cured in ten days; others require a month, according to the severity of the case. I have occasionally seen reproduction of the follicles requiring repetition of the operation. Efficient and truly curative treatment consists in excision of Fig. 134. the redundant folds at the cul-de-sac. For many years I have, in selected cases, done this, and fully recognized the importance of not doing it to excess, and of careful judgment in the selection of cases. I strongly deprecate resort to such a method in ordinary cases, but for some it is adapted. Galezowski has followed this 350 DISEASES OF THE EYE. practice. It is only when the folds are very loose that excision is proper. It may be done with forceps and scissors, leaving sufficient tissue not to restrain free movements of the conjunctiva after cicatrization shall have occurred. It is also important not to go so deep as to damage the thin expanding tendon of the levator. The effectiveness of the squeezing process, of which the method is indicated in the sketch (Fig. 134), renders excision unnecessary. I may add that the forceps depicted are more workable and will give access to the semi-lunar fold and to the recesses at the angles much better than either ring forceps or a roller forceps. One must always employ two and often give an anaesthetic, because the proceeding is severely painful. Chronic Trachoma.—We have to consider first the simple con- dition where isolated granules or groups of them lie imbedded in an apparently normal membrane, or we may have the case of an old trachoma with a few hard and red deposits lying like boulders on a devastated plain where the fury of a fire has been spent. To both these classes of cases similar treatment is suitable. In the former instance there may be no history of previous trouble, in the latter there has been a long-standing lesion of which the ex- isting status is the remnant. In this the slight irritation will be soothed by lotions of boric acid 3$, or of sublimate, 1 to 10,000, or po- tass chlorat. 2$. But the effective remedy is to pick out with a needle or squeeze out with cilia forceps the imbedded granules. If this cannot be effectively done, the forceps previously described, or the ring forceps of Prince, or a roller forceps of Knapp may be em- ployed. When the expulsion is accomplished, sol. nit. arg. gr. ij.-iij. ad 3 i. may be used every second or third day in addition to the lotions. For the second class of cases more rigorous means are needful, and the best success is by burning the separate masses with the galvano-cautery, or the fine point of a thermo-cautery (Paquelin), or by a hot needle. With cocaine several may be de- stroyed at once and all at two or three sittings. After-treatment will be indicated by the conditions—perhaps light touching with sulph. copper or alum stick, or solutions of sublimate, 1 to 3,000, as may be suitable. Before discussing local treatment further, it must be insisted on that severe cases, i.e., those with considerable pannus or thick- ening of the conjunctiva, with hyperaemia of the bulbar membrane, with acute photophobia and lachrymation, cannot be successfully dealt with unless placed in good hygienic conditions. They need protection from wind, dust, smoke, and bad air. They may have to go to hospitals, but the utmost pains must then be taken to secure free ventilation, good food, and absolute cleanliness in hands and person, clothing, utensils, habits, and surroundings. When THE CONJUNCTIVA. 351 such conditions are fulfilled, and they are difficult to fully realize both in hospitals and in the houses of the poor, the battle is half won. Frequently a patient must stay in bed a good part of the day to permit the continuous fomentations; but sufficient exercise must be given to secure good digestion and assimilation. Some- times with absolutely perfect hygienic conditions the disease as- sumes an acute type, and then we have to contend with a feeble or strumous constitution. It is very rare for trachoma to develop acute and obstinate forms among healthy persons in healthy con- ditions. Next we discuss the cases of chronic or mixed trachoma. The hitherto established treatment consists in sol. nit. arg., gr. v.-x. ad 3 i., every second or third day to the everted lids, if possible reach- ing the retro-tarsal folds, or the more painful sulphate of copper in crystal, or for mild cases the daily use of a crystal of alum. By some the yellow oxide of mercury ointment, gr. v. ad 3 i., or pow- dered boric acid is rubbed on the everted lid with the finger: tan- nin and slycerine, gr. xx. ad 3 i. or stronger, is employed during the late stage when cicatrization and patches of hyperaemia ap- pear. As a lotion, to be used several times daily, nothing equals sol. corrosive sublimate, 1 to 3.000, pro re nata. Under the plan thus sketched cases get well after many months, with liabilities to acute exacerbation and prolongation of the disease for years. Because the poor are the usual victims, their necessities compel them to omit treatment as soon as they can return to work. Soon they present themselves again, and the process must be begun de novo. In view of the obstinacy of the malady, and the conviction that its malign character is found in the presence of micro-organisms which provoke cell growths and other changes, and guided by the beneficent effect of corrosive sublimate in collyrium, a vigorous and effective employment of this remedy has of late years been widely adopted. In strong solution, 1 to 500, it is painful and caustic. This has been used in France and Italy after cocaine anaesthesia, once and even three times daily to the everted lid, while a solution, 1 to 120 (Arnaut's), has been twice a week employed. Von Hippel, whose judgment and experience are worthy of respect, reports good re- sults in 300 cases, by vigorously rubbing the surface with sublimate sol., 1 to 2,000, once daily by a mop of cotton. The severity of the friction is proportioned to the density of the tissue—if soft and much swollen it will be light, if hard and the follicles firm it will be ener- getic. The endeavor is to rub out the contents of the follicles and the lymphoid infiltration. In some cases of diffused thickening and infiltration this is impracticable, but even in them the treatment is greatly effective. Cocaine is needful, but on repetition the treat- ment is less painful than at first. With hyperaemic and soft tissues 352 DISEASES OF THE EYE. the reaction may be sharp and require cold lotions for several hours. On the following day there will be a thin layer of gray exudation, which is easily removed, and the proceeding may be renewed every day during the first week. In old cases with beginning atrophy exudation does not appear. Pannus and slight erosions of the cornea respond favorably, unless the conditions are severe or there be co-existing iritis. Heisrath, commenting on this treatment, re- ported good results, but stated that he had seen instances where the healthy cornea became ulcerated and infiltrated (Berlin. Klin. Wochensch., 1891, No. 5). When the follicles disappear treatment of the chronic catarrh which remains " requires lotions of acetate of lead, 1 i, and discontinuance of the rubbing." Some caution must be given as to the use of lead lotions at any period of such cases. Alum or weaker sublimate solution or boric acid will be safer, and sol. nit. arg., 1 i, or light use of copper will be proper. Von Hippel does not make extraordinary claims for this treatment, but holds it superior to our old methods, and in this he is supported by others. To his statements1 so much space has been given because his experience leads up to another plan which embodies the same ideas and which has been practised and witnessed by myself ex- tensively during the past year. The fundamental ideas are to get rid of the follicles and lym- phoid infiltration, to apply sublimate solution in effective but not destructive strength, to avoid such violence either mechanical or medicinal as will provoke development of fibrous tissue; when the follicles have disappeared to treat the case as one of chronic conjunctivitis. Severe reaction, if present in the cornea, must first be made to subside and must not be excited by treatment. Es- pecially must iritis be respected and brought under control by atropia, and all irritants until then be avoided. The removal of the follicles is best done by the two pairs of for- ceps referred to on p. 348. I find them superior in most cases to roller forceps. But if the tissue be somewhat firm and the lym- phoid infiltration cannot be sufficiently expressed, a more heroic method is practised, which was first instituted in Abadies clinique in Paris. An anaesthetic is given; the lid is rolled completely out- ward by a small pair of dressing forceps. (A special forceps has been contrived by Dr. Gibson which is of decided advantage in not cutting the edge of the lid and in securing full control—Fig. 135). The fornix is fully exposed and the membrane lightly incised by a three-bladed scarificator in parallel lines about 2 mm. apart. With a rather soft tooth-brush the corrosive sublimate, 1 to 500, is rubbed into the lid and the bleeding checked by wads of cotton dipped in the same solution. The epithelium is of course considerably de- 1 Bericht Ophth. Gesell., Heidelberg, 1892, p. 91. THE CONJUNCTIVA. 353 stroyed and wiped away, but one must not deal harshly with the tissue. The depth of the scarifications, their number, and the vigor of the brushing must be in proportion to the induration and thick- ness of the structures. The eyes will be covered with cotton soaked in the same solution and bandaged firmly for a few hours to pre- vent undue swelling. In a markedly lymphatic patient reaction will be severe. There is always considerable secretion the next day and the surface will be covered with a gray pellicle. Some swelling will occur and cold lotions be necessary. Sublimate solution, 1 to 500, will be applied daily to the everted lids by a little mop, taking care to reach the fornix and prevent formation of ad- hesions. If severe reaction contra-indicate the sublimate, the manipulation will not be omitted. A patient will remain in hos- pital about a week, less or more. As already intimated, the cases suitable for the above proceed- ing (" grattage ") are those in whom squeezing by forceps cannot sufficiently remove the lymphoid infiltration because it is buried amid great general thickening, which also prevents the effective contact of the sublimate with the tissue. Experience has shown Fig. 135. that while a rapid removal of the granular thickening is effected and the hazy cornea clears up, there is a tendency to production of connective tissue which may easily induce unpleasant deformity of the lids, causing bridles, ridges, and degrees of symblepharon. In numerous instances it has been found that the superior fornix, six months after a judiciously mild grattage, has been obliterated. This condition may not be important, but one must not let zeal for a rapid cure run into rashness which may occasion deformity. Such cautions seem needful lest enthusiasm in behalf of a valuable method of treatment overstep the limits of prudence. In public institutions where children are assembled there is especial fitness in the sublimate treatment, and it soon establishes a practically aseptic condition among the patients which is the great desidera- tum. It is also to be remembered that steady treatment must be continued by usual remedies for weeks after the first favorable im- pression by squeezing or sublimate, or both, has been made. Cases of less duration and severity, and especially such as con- sist largely of papillary hypertrophy, do well enough under the nitrate of silver gr. v.-x. ad 3 i., where there is decided secretion, 23 354 DISEASES OF THE EYE. or sulphate of copper where there is little of it, but the present tendency is to use sublimate solutions in all cases for which me- chanical means are not indicated. My most recent experience favors solutions of sublimate 1 to 600 or 1 to 1,200 rubbed upon the lid with a small cotton mop daily or once in two or three days, in moderate cases, as the most satisfactory proceeding. " Grattage " will be reserved for the more obstinate. In them a canthotomy is. often requisite to sufficiently expose the field of operation. A repe- tition of squeezing or sometimes of grattage may be necessary. In former days cantholysis was often employed to help alleviate the corneal lesion; we now resort to it only when deformity of the lids, " phimosis," indicates its necessity. It will be referred to later. I have in a few cases of extreme and general thickening of the conjunctiva used the Paquelin thermo-cautery once in ten days or two weeks and with considerable vigor. It has served me well, and the subsequent fibroid degeneration was not excessive, although it was considerable. The cases were exceptionally severe, and the remarkable feature was the moderate reaction after extensive burning. As the thickening of the conjunctiva subsides, the corneal trou- ble will, pari passu, abate; when, however, the cornea has become very opaque and vascular, the vessels thick, the epithelium dense and the surface insensitive, the sulphate of copper may be applied directly to it, and with advantage. Excision of the conjunctiva for the breadth of one-fourth of an inch around the entire circumfer- ence of the cornea has been employed under the name of peritomy, and has been of some service, but it is far less resorted to now than in former days. Curetting the corneal surface by a small knife has been done by Dr. Gruening, and with improvement and little reaction (see Trans. Am. Oph. Soc, 1889). In these extreme cases, and also in cases less severe, improve- ment of vision has been sought for, especially in Belgium, by resort- ing to inoculation with blennorrhoeal pus. In doing this an acute purulent conjunctivitis is set up which is left to run its course with but little interference, occupying from four to six weeks, and in some cases valuable improvement in the cornea has been obtained; there is, however, always risk of the destruction of the cornea and of sight. This proceeding is at the present time little employed. Within a few years an infusion of the jequirity bean, a Brazilian plant, abrus precatorius, has been extensively employed in treating not only the advanced and extreme cases of granular lids, but all forms of the disease. Brought to notice by Wecker, of Paris, in 1882, it has had large trial, and experience up to the present time seems to show that its chief value is during the later stages and when the cornea has become seriously vascular. The bean is to be THE CONJUNCTIVA. 355 powdered and macerated for three hours in water of the ordinary temperature in the concentration of about 3$ (Wecker).1 The in- fusion when old is not as effective as when recent. With a brush it is applied two or three times to the lids; within twenty-four hours reaction should appear; if it do not, the application may be re- peated. The mucous surface becomes covered with a grayish membrane which adheres for days. The lids swell, copious secretion occurs and the cornea is apt to become very hazy. The patients suffer pain, and iced water is to be freely employed. The inflamma- tion will run for two weeks or more, and in favorable cases not only does the cornea clear up, but the conjunctiva recovers a much more healthy appearance and old cicatrices become softened. The secre- tions from this inflammation are not contagious. The active principle of the plant is called abrine and is regarded as a ferment; there is no specific microscopic germ associated with it. A patient who has once been treated by jequirity, though less susceptible, may be again brought under its influence. If it be em- ployed in unsuitable cases, or with too great freedom, suppurative inflammation or even destruction of the eye may follow. The rem* edy is to be used with safety only in inveterate cases where other remedies have failed and where vision is seriously impaired. Its non-contagiousness permits its use when one eye only is affected. It is never right to inoculate both eyes at once. Coppez, who treats in Belgium a great many cases of trachoma, sometimes uses the infusion as strong as 10$. But the cases must be extremely severe and unyielding to warrant the proceeding. Similarly the jequirity infusion is employed in so-called scrofulous pannus of the cornea not caused by granular lids, and also in sclerosed conditions of the cornea after parenchymatous keratitis. It has been tried to a limited extent in torpid ulcers, but not with advantage. It is imperative to know that for cases of simple chronic blennor- rhoea, or chronic conjunctivitis, its use is contraindicated, because it is likely to do serious mischief. So, too, in recent trachoma with succulent hypertrophy and moderate secretion it is not a safe remedy. When the conjunctiva is hard, nodular, or cicatricial and the cornea decidedly opaque, it becomes a useful agent. It is employed by some surgeons (Roosa, Cheatham: see also Widmark, " Beitrage zur Ophth.," Inaug. Diss., 1884-1891) at the present time, but it is far less in vogue than five years ago. It sets up a very uncomfortable reaction and threatening appearances. The methods previously described are in my esteem to be preferred. In summing up the treatment, while old and well-established 1 Others have used a smaller quantity, say one bean to an ounce of water and infused for twenty-four hours. 35G DISEASES OF THE EYE. principles and methods have been reiterated, certain new proceed- ings are set forth, viz., the squeezing by forceps of flabby, gelatin- ous, extremely redundant masses of granules; exceptionally they may be excised; the picking out the contents of the granules with a broad needle, scraping the tarsal conjunctiva with a sharp curette or by a fine rake so as to get rid of moderate prominences. The same effect is attained by touching the granules with a hot needle. For large masses, whether left as isolated projections in old cases or occurring as general and extreme hypertrophy, a more decided use of the actual cautery is proper, viz., the thermo-cautery of Paquelin. For this and sometimes for the use of the forceps an anaesthetic as well as cocaine will be needful. (Mem. Ether is in- flammable, chloroform is not.) For chronic cases, grattage, with or without expression and canthotomy, is a recent valuable resort. Like all surgical methods it demands good judgment. The infusion of jequirity will im- prove vision in desperate cases, while it, too, demands care and discrimination. It happens that patients cannot always remain under the hands of the surgeon for the completion of the treatment of this tedious disease, and it becomes advisable to instruct a friend in the manip- ulation of turning the lids and applying either sol. tannin and glycerin, alum crystal, or the sulphate of copper crystal. In case the patient must depend wholly on himself, he may be supplied with an ointment of sulph. cupri, gr. v.-x., ad vaselinum, § i. The vaseline may in warm weather be stiffened with powdered gum arabic or starch. The usefulness of corrosive sublimate solution will vindicate itself, and an ointment of hydrarg. oxid. flav., gr. x. ad 3 i., once or twice daily between the lids is well worth trial. The necessity of remitting active treatment when relapses of inflammation occur, as they may frequently, must not be forgotten, and then warm water and atropine will be the best relief. The use of the latter is often kept up during the continuance of the local stimulants. Sometimes with prominent eyes the lids in the atro- phic stage of trachoma are left so shortened as to press disagree- ably on the cornea. Canthoplasty may have done all that it can, and the skin operation above described (see p. 278) may not be desirable. In such cases, continual pulling at the skin of the tem- ple, forehead and cheek, a kind of massage, will, in time, loosen the subcutaneous connective tissue and secure some relief. Xeroma of the conjunctiva, which is the stage of consummate atrophy of the membrane, only admits of palliation by emollients, such as vaseline or olive oil, several times daily. An admirable summary of treatment of trachoma has been published by Sattler, " Die Trachombehandlung einst und jetzt," Berlin, 1891, p. 44. THE CONJUNCTIVA. 35? Sequelae of Granular Conjunctivitis.—The secretory glands become obliterated, the conjunctiva cannot supply the proper amount of fluid, and hence there is an unpleasant dryness and irri- tation of the lids. By the shrinking of the tissues the hair follicles are distorted, the hairs become few and some or many or all of them may be turned upon the globe. In other words we have trichiasis or entropium. In the latter condition the palpebral fissure is shortened, the lids cannot be sufficiently separated, the tarsi become prominent and are shrivelled into dense ridges. The cornea loses transparency and its curve becomes altered in irregu- lar forms. To the casual observer it may seem normal, but a test of the acuity of vision and the failure of glasses to improve it will show how serious is the mischief. If examined by the ophthalmo- scopic mirror (preferably by the plane mirror) or still better by the ophthalmometer of Javal, the corneal irregularity becomes apparent. It may become conical and no satisfactory view with the upright image will be possible. Treatment of some of the above conditions has already been described when discussing affections of the lids (see Entropium and Trichiasis, etc., pp. 262, 276, 278), and those which concern f.he cornea will be hereafter referred to. Sometimes during the progress of the treatment of trachoma, the lids become tight or even short- ened, the cornea is greatly irritated, and the operations of can- tholysis or canthoplasty are resorted to to check the distressing symptoms. A. few years ago these proceedings were employed very frequently, but their use is now more limited, yet occasionally suitable. The writer's experience in one extremely bad case for which relief was gained by subcutaneous division of the superior tarsus on its median line may be again referred to (see page 267). To operate during acute symptoms will often aggravate them, while the free use of cocaine and other measures, such as cold lo- tions, etc., will control the condition. Partial ptosis is not infrequent. It may be corrected by deep sutures from the orbital margin of the tarsus, carried up under the edge of the orbit by a curved needle, and tying the sutures tight to remain several days. A similar operation might also be done on the conjunctival surface with excision of some of the fornix. 6. Morbid Growths on the Conjunctiva.—Under this head are included syphilitic lesions, tubercular deposits, epithelial, lupoid, and cancerous disease, amyloid degeneration, cystoid growths, congenital fibrous growths, papillomata, even a bony growth has been observed and calcarous deposits occur; we also have angio- mata, and pigment patches. The syphilitic lesions of the conjunctiva occur oftenest in the 358 DISEASES OF THE EYE. papebral portion, under the form of chancre or of mucous patches. On the bulbar portion gummy tumors have been seen, and while they often include subjacent structures, sometimes their mobility shows that only the conjunctiva is affected. The diagnosis cannot with certainty be made from local appearances, but rests also upon constitutional symptoms. Mucous patches have also been seen on the ocular conjunctiva. In all these lesions it is usual to find swell- ing of the pre-auricular lymphatic gland of the corresponding side. As has been said, we may have upon the conjunctiva either the primary, the secondary, or the tertiary lesions of syphilis. Cases of this kind are rare, yet they must not be overlooked. Among many contributions to the subject are papers by Bull,1 and by De Beck 2 in which the literature is extensively quoted. Local treatment will be the same as would be proper if the lesion were on another locality, save that cauterization of an ulcer must be done so as not to harm the cornea, and the liability of this structure to suffer mischief will modify the proceedings. Soothing applications will be preferred, such as atropia and the milder anti- septics, boric acid, diluted chlorine wrater, iodoform, etc. The chief dependence will be on constitutional treatment. Within the last few years attention has been much called to tubercular disease of the eye, which may invade any part of it, and has been found in the conjunctiva, both of the lids and of the globe. The tendency of the disease is to attack in its progress deeper structures, and it presents ordinarily an open ulcer, with grayish surface, from which nodules spring up either within its area or upon its margin. The disease more frequently seizes upon the inner than upon the outer structures of the eye primarily, and reference will be made to it again. The chief importance attaches to diag- nosis, and we have to distinguish tubercular deposit from granuloma and from lupus. The former (granuloma) is a firm, reddish, highly vascular mass of uniform character, and the neighboring lymphatic glands are not swollen. Persons of any age may be affected. A tubercular deposit is a mixture of nodules and ulceration, it in- volves all the tissues of the part affected, its edges are beset with trachoma-looking masses. In lupus the skin is generally also affected; Arlt, 1863, speaks of two cases in which the disease began on the conjunctiva bulbi, and the eye was attacked by continuity of invasion. In tubercle we find giant cells, and the peculiar bacilli. In lupus we also find bacilli closely resembling those of tubercle, and at the present time the two diseases are coming to be regarded as essentially the same. 1 " Syphilis of the Conjunctiva," by C. S. Bull, Anier. Journal of Med. Sciences, Oct., 1878, p. 405. 2 " Hard Chancre of the Eyelids and Conjunctiva," by David DeBeck, Cincinnati, Ohio, 1886. Press of Robert Clarke & Co. THE CONJUNCTIVA. 359 There is no satisfactory treatment of tubercular deposit in the lids, and if it occur upon the globe, enucleation will be the ultimate resort. The suitableness of operating for tuberculous disease of the lids will depend on the stage of the disease and on the state of the patient. He is usually young. If possible, thorough excision should be done, to guard against general infection. There are numerous cases recorded in literature, but one which is typical and carefully described is by Baumgarten.1 Epithelial disease and lupus attack the lids quite frequently, beginning at their margin. They may, if neglected, extend to the globe (see Plate VI., Fig. 18, colored illustrations). We also some- times find an epithelioma as a reddish lobulated mass growing at the limbus corneae. A tumor of this kind which displayed the char- acteristic microscopic structure I removed from a man fifty-seven years old, and it has not recurred for nine years. I have also re- moved a pigmented (melanotic) epithelioma from the same region, and with no recurrence up to the present time. For details of the case and references to the literature, see A rchives of Ophthal. and Otology for 1879. Cancerous ulcerations may attack the ocular conjunctiva. I have notes of such a case. Sarcoma,either white or pigmented, may also appear, and while removal of the disease without sacrificing the globe is to be pre- ferred, such a course is not always possible. Complete removal is imperative and that will often compel the loss of the globe. Papil- loma is found at the inner canthus as a favorite site and is easily recognized by its softness, its clefts, and its small pedicle. In the lesions now considered other organs, such as the lymph glands, the lungs, the liver and other viscera, are to be scrutinized to learn the true meaning of the case. Cysts sometimes appear beneath the conjunctiva, usually on the globe, sometimes over the caruncle. Their contents are commonly watery, sometimes oily or sebaceous. Young persons are more often the subjects. The sac may grow to hold as much as two drachms of fluid and sometimes it reaches back into the orbit. (The occurrence of true orbital cysts is not meant.) Their walls are usually very thin, and their transparency suggests their char- acter. Greater firmness has, however, been observed. Treatment requires either simple puncture, or besides this a silk seton, or if obstinate, cauterizing the wall with nitrate of silver. See an article by Dr. C. S. Bull.2 Fibroid tumors, or more properly dermoid growths, appear on the ocular conjunctiva, and especially as a congenital formation. 1 " Ein Fall von tuberculosen Greschwiiren der Lid-Conjunctiva," Graefe's Archives fur Ophthal, Bd. xxiv., Abth. hi., S. 225. 3 " A Study of Sub-conjunctival Serous Cysts," Amer. Journal of Medical Sciences, Jan., 1878, p. 85. 360 DISEASES OF THE EYE. There may be more than one, and there may be stiff hairs growing upon them. A not infrequent condition is to find at the outer angle a dense plate of hard tissue with thick white covering pushing for- ward from the orbit usually on the temporal side upon the sclera, half-way perhaps to the cornea, with a thin, rounded edge. It is imperfectly movable, but with a rigid base, and resembles to some extent the plica semilunaris of rabbits and sheep. Between it and the cornea may be small hard tumors. This is a congenital mal- formation. A careful description of such a case and an account of others is given by Hirschberg.1 A tumor of similar kind was described by Graefe as coming from the orbit between the rectus superior and rectus externus muscles from the superior fornix. I have notes of the case of a man who had three hard sessile dermoid tumors growing upon the limbus corneae about equidistant from each other. The outer angle of the lids was tied by a band of fibrous tissue which stretched across it and also adhered to the conjunctiva bulbi. A similar band ran across the inner angle be- tween the lids. These bands were quite dense and prevented the lifting of the lid. The condition was congenital. The other eye was normal. Tumors like the above may be removed to get rid of a blemish, but if they reach into the orbit, the rules of antiseptic surgery must be strictly observed, because the proceeding becomes serious. Pinguecula is the name given to a small yellowish elevation be- tween the semilunar fold and the edge of the cornea. It consists of connective tissue, elastic fibres, and epithelium, and contrary to the import of its name it does not contain fat. Most persons in adult life or at its later periods will present this little elevation more or less conspicuously. It causes no harm, never becomes large, and is not to be meddled with. Pigment patches of a brown or even deeper hue are sometimes seen on the conjunctiva; they may be stationary and innocuous, or they may increase, and they may be associated with co-existing pigmented malignant growths. Angioma sometimes occurs. Its most frequent seat is the car- uncle. In the same region we find more frequently polypoid growths or granulomata. In gouty subjects cretaceous deposit is sometimes found in the conjunctiva. Loring2 has reported the remarkable fact of a bony growth. Xerosis of the conjunctiva or its extreme degeneration and atrophy is brought about by trachoma, is a result of pemphigus 1 Centralblatt fur Augenheilkunde, Jahrg. vii., S. 295, 1883. 4 " Case of osteoma of the conjunctiva," by Dr. E. G. Loring, New York Medical Journal, xxxvii., p. 12_, 1883. THE CONJUNCTIVA. 361 also appears in small glistening patches three or four millimetres across upon the inter-palpebral ocular conjunctiva, and lastly hap- pens idiopathically to the production of complete symblepharon when it reaches its ultimate development. Taking up the third form, we remark that these satiny white spots were described by Kuschbert and Neisser and also by Leber,3 and have a special interest because bacilli and cocci are found in them. In some instances the patients have the form of amblyopia called hemeralopia. The connection between the two facts is not explained, nor do they always concur. When these patches exist there is also a little foamy secretion gathered along the edges of the lids due to fatty degeneration of the cells, and in some instances the cornea becomes infected and ulcerated by the penetration of the microbes. The disease occurs mostly among children and especially among the poorly nourished. It was observed as early as 1874 by Bezold, and by Horner in 1877: the lesion of the cornea was severe and the dryness of the conjunc- tiva was regarded as incidental. Leber considers degeneration of the epithelium the first step, followed by loss of sensibility through injury to the terminal nerve twigs; the consequence is imperfect closure of the lids and additional dryness of the conjunc- tiva—naturally the cornea becomes most seriously exposed to ulceration. The same kind of degeneration takes place in the epi- thelium which clothes the pelvis of the kidney, and the same micro- organisms are found as in the conjunctival epithelium. Cultivation of these was found to cause the corneal lesion and also the degen- eration of the conjunctiva. For cases among negro children, see Kollock, Trans. Amer. Oph. Soc, 1890, p. 626. Leber proposes to give the name xerophthalmus to the altera- tion which follows trachoma and which includes atrophy of the whole membrane, but he points out that this condition may arise without trachoma, and both he and Arlt have noticed that it may be attended with atrophy of the lachrymal gland. There is almost complete absence of normal secretion, which can be only imper- fectly supplied by water containing \