Read before the Philadelphia €unn 
June 27, /fejjoRFON GENERAL'S C 
SOME OBSERVATIONS ON CORNEAL ASTIGMATISM 
AND CONDITIONS THAT CHANGE 
CORNEAL CURVATURE. 
LOUIS J. LAUTENBACH, A. M., M. D., Ph. D. 
PHILADELPHIA. 
SURGEON TO THE PENNSYLVANIA EYE AND EAR INFIRMARY; THROAT AND NOSE PHYSICIAN TO 
ODD FELLOWS’ HOME, ETC., LATE CHIEF OF EYE AND EAR CLINIC, GERMAN HOSPITAL. 
The object of this paper is to call attention to a not infre- 
quent phenomenon met with by those who work much with 
the opthalmometer, viz., changes which occur in corneal 
curvature. 
You will recall that up to about twenty years ago the 
cornea was considered to be sufficiently hard and firm as to be 
unchangeable, unless inflamed; and that the astigmatism of the 
eye remained the same throughout life, undergoing no change 
of any kind. Of course there were numerous cases in which 
an astigmatic refraction ordered by a skillful ophthalmologist 
was changed to a cylinder of different degree of axis, or both, 
by another opthalmologist equally skillful, the latter contenting 
himself with the thought that the first correction was not 
accurate. Doubtless often both pairs of glasses were correct at 
the time prescribed, the corneal curvature having changed in 
the interim. 2 
CHANGEABLE CORNEAL ASTIGMATISM. 
Of late years it has been scientifically demonstrated that 
in cases of glaucoma there is a change in the curvature of the 
cornea accompanied usually by a change in the relation of the 
axis of greatest curvature—that of the horizontal meridian 
becoming more curved, and the vertical more flattened. The 
increased pressure from within is often manifested in this way 
before any of the marked glaucomatous symptoms appear. An 
eye which undergoes a change of this kind, an increase in 
curvature of the horizontal meridian, should be watched with 
suspicion. 
The subject of the changes of corneal curvature after 
cataract operations has attracted considerable attention in the 
past few’ years. It seems evident that if a curved surface l»e 
incised and the edges of the incision be separated by a mass of 
lymph, the curvature will be changed; and as the mass of 
lymph is gradually absorbed, so gradually will the curvature 
approach the more nearly to its original condition. If the 
Graefe incision be above or below, the effect will be to flatten 
the horizontal meridian; while if to the side, the vertical 
meridian will undergo a like change. 
Besides these changes in corneal curvature there are others 
which occur in cornea.* apparently poorly nourished, especially 
in patients of rheumatic, syphilitic, turbercular, or scrofulous 
diathesis. These changes occur not only from day to day, or 
from week to week, but also instantaneously, apparently as the 
result of the pressure of the lids and the external eye muscles. 
/ have Jound the corneal astigmatism to change from two to three 
diopters in perhaps eight or ten seconds, and the axis as much as 
2in these cases. These changes have been noted not alone in 
one case, but perhaps in from fifty to sixty patients. The vari- 
ations have of course been rarely as great as here noted, usually 
changes of from 0.25 to 1.00 diopters being noted. The instru- CHANGEABLE CORNEAL ASTIGMATISM. 
3 
ment by which these observations were made was the Javal- 
Schiotz ophthalmometer, made for me in 1892, by Myrowitz, 
of New York, and was used in the manner described by me in 
the New York Medical Journal, viz., strapping the head firmly 
in the head-rest, with the patient’s arms resting on the table 
and the feet on the floor. 
When first observed these sudden changes in the corneal 
curvature gave rise to the suspicion that something was wrong; 
that perhaps the apparent change in curvature must be due to 
a change in the depth of the layer of conjunctival fluid on the 
cornea. Guarding against this by the closure of the eyelids 
and the taking of new observations, as well as by the use of 
castor-oil or glycerin on the cornea, the same results were 
obtained 
Of interest in this connection, and confirming the 
observations, is the fact that the majority of these cases were 
examined at frequent intervals after they were put on local as 
well as dyscrasic treatment, and as their general health im- 
proved not only did the curvature become more constant, but 
the vision improved as well. May not some of the many cases 
of spasm of accommodation of which we have heard be truly 
relegated to cases of weakened corneal tissue with instantane- 
ous changes in its curvatures? 
I believe this change in the curvature but rarely occurs in 
good healthy cornese, not that there could not be theoretically 
sufficient pressure from within or without to occasion it. I 
believe it to be not infrequently present in the rheumatic and 
gouty, in the scrofulous and syphilitic, and in tuberculous 
subjects. Nearly all of these cases have been either in patients 
suffering from the above constitutional weakness or in those 
convalescent from long-continued fevers. In many cases I 
have observed the amount of corneal astigmatism of the prin- 4 
CHANGEABLE CORNEAL ASTIGMATISM. 
cipal axes to be altered under the influence of a mydriatic. In 
glaucoma the corneal nutrition is interfered with and at the 
same time the extra pressure from within is exerted upon the 
weakened cornea. 
These observations will in some part explain those cases which 
wander from doctor to doctor, obtaining from each a prescription 
for a pair of glasses, none of which prove of positive value to the 
patient. To such patients no astigmatic glasses can be of use until 
the nutrition of the cornea is so thoroughly restored that the curvatures 
remain constant. These cases will demand, first of all, careful 
examination, and after the diagnosis of changeable corneal 
curvatures is made then the history' and general health must be 
carefully studied, and when once the diagnosis is accurately 
made, treatment must be directed to the general as well as the 
local conditions. When the cornea becomes more thoroughly 
nourished, the curvatures remain more constant, and there is 
little or no variation in the axes. We are now almost ready to 
order glasses should such lie deemed necessary. 
Glasses ordered before this fixity in the curvature has been 
obtained unil prove but a source of annoyance, whereas, if ordered 
afteru'ard will be a source of comfort and relief. 
I have endeavored to give but a sketch of a truth—namely, 
that well-nourished cornea* withstand the ordinary variations 
of pressure exerted from within or without, without causing 
any material change in the principal axes or in the curvatures, 
whereas, if the cornea are poorly nourished these variations 
are often sufficient to change materially r.ot only the curvatures 
but also the principal meridians. Abnormal or extreme changes 
in pressure, w-hether exerted from without or from within the 
eye, are attended usually by a change in corneal curvature as 
well as by an occasional alteration in its principal meridians. 
1773 Walhut Steeet, Phil’a.