A Few Thoughts about Ophthalmometry, 
as to what the Javal Instrument will 
do, and what it will not do. 
BY 
LOUIS J. LAUTENBACH, A.M., M.D., Ph. D., 
PHILADELPHIA, PA. 
Surgeon to the Pennsylvania Eye and Ear Infirmary, Chief of the Eye 
Clinic of the German Hospital, Etc. 
Reprint from The Ophthalmic Record, December, 1893. 
NASHVILLE, TENN,: 
A. II. Gray & Son, Book and Job Printers 
1893. A FEW THOUGHTS ABOUT OPHTHALMOMETRY AS 
TO WHAT THE JAVAL INSTRUMENT WILL 
DO, AND WHAT IT WILL NOT DO* 
By LOUIS J. LAUTENBACH, A.M., M.D., Ph. D. 
Philadelphia, Pa. 
Surgeon to the Pennsylvania Eye and Ear Infirmary, Chief of the Eye 
Clinic of the German Hospital, Etc. 
The value of the Ophthalmometer, as a factor in the deter- 
mination of the axis and amount of astigmatism, has for the 
past few years, given rise to considerable controversy. Accord- 
ing to some it would seem as though the ophthalmometer had 
supplanted the subjective test, rendering the use of mydriatics 
unnecessary, and those who used them liable to be considered 
old fogies, " too sot in their ways " to appreciate the value of the 
more perfect and scientific method. Others consider it little 
more than a toy whose popularity will be ephemeral; and con- 
tent themselves with the assurance that it, like many other 
medical fads, rests on an insecure foundation and will therefore 
soon be a thought of the past.' Again, there are those who 
consider the instrument a scientific one, constituted on proper 
* Read in the Section of Ophthalmology, Pan-American Medical 
Congress, 1893. 2 
Ophthalmometry. 
principles, and not a toy; yet know that the scope of its work 
is limited, and have endeavored to get from it all that is pos- 
sible ; and, while acknowledging its great usefulness, realize its 
limitations. 
Those who have used the ophthalmometer, in other words, 
those who from experience know something of it, naturally be- 
long either to the first or third group. Originally, the larger 
number of them belonged to the first, class ; but the third or 
conservative class has been steadily growing, and now contains 
quite a respectable number of the thinkers, or in other words, 
it contains the workers and reasoners, and not the' enthusiasts. 
The main reasons for this difference of opinion consists, 
firstly, in a faulty construction of the instrument; secondly, to 
a faulty use of it; and thirdly, a wrong interpretation as to 
what can be accomplished with it. 
Glancing for a few moments at the different ophthalmometers, 
we have to consider first, the original instrument constructed by 
Helmholtz in 1853. This instrument is really perfect in con- 
struction giving us most accurately the radius of curvatuie at 
any part of the cornea desired. Its results are accurate, but its 
use entails the expenditure of a large amount of time :-to 
thoroughly measure the cornea at any point necessit ites at least 
sixteen separate readings. It has been used by Knapp of New 
York, and Strawbridge, Wieland and others of Philadelphia. 
All testify to its accuracy and perfectness, but consider it more 
valuable in the laboratory than the office. 
The ophthalmometer of Lelloy and Dubois has the disadvan- 
tage of being poorly constructed, the hinge and other joints 
being loose; in fact, nearly all the fittings arc inaccurate. 
There is no means of steadying the head so that the eye may 
be fixed while being measured ; the scale is inaccurate; the bar 
on which the mires or reflectors ride is straight, whereas, it 
should be an arc of a circle with a radius equal to the distanco Louis '7. Laulenbaeh, A.M., M.D., Ph. D. 
3 
of the scale from the eye being examined. It has no means of 
artificial illumination, while requiring for its proper use a very 
strong light. Some pretend that by its use, the refraction of 
the eye ball can be determined. The claim is, however, too 
absurd for discussion, as it must be evident that it is a physical 
impossibility to determine this objectively. 
The Javal-Schiotz ophthalmometer of 1889. if mechanically 
well constructed, is a good instrument. Its most frequent 
defects arc a displacement or a malposition of the Wollaston 
bi-refrangent prism; a displacement of the arc upon which the 
scale is constructed and the mires move; the want of a means 
of keeping the patient's head fixed while under examination, 
and an insufficient illumination. 
Tn the Javal instrument (model 1889) of French construction, 
the base is too light; it does not keep the telescope and head- 
rest in a fixed relation to each other; and in the general work- 
manship, it is markedly inferior to that of American construction. 
A malposition or displacement of the Wollaston prism is 
frequent. Instead of the primary image revolving about its 
centre with the revolution of the telescope, it has in addition, 
another motion about an imaginary centre, the secondary image 
in either case moving about the primary one. This double 
motion of the primary image is due to a faulty position of the 
prism; and before using such an instrument it should be carefully 
overhauled, as all results obtained under these conditions are 
absolutely worthless. If the arc be not in proper position-if 
it is not at all points exactly the same distance from the eye, 
again are the results valueless The screws by which the arc is 
fastened to the barrel of the instrument must be very carefully 
adjusted. In order to test the arc, a lens with a refractive 
pow >r of its anterior surface of about 32 diopters should be 
placed at the rest of the instrument. If, as the telescope is 
revolved, there be the slightest break in the continuity of the 4 
Ophthalmometry. 
black lines of the mires, it indicates that the arc is still im- 
properly adjusted. 
With a properly constructed instrument, a good illumination 
(four incandescent lights of sixteen candle power being un- 
doubtedly the best), the apparatus firmly secured to a good 
stout table, and the patient's head firmly fixed (strapped in the 
head rest), the results will be trustworthy and accurate. It is 
for us to interpret the results. 
Here let us pause and inquire as to what has been expected 
of the instrument, and how far our anticipations have been 
realized. 
There are those who have assured me that it would measure 
the refraction in any meridian. It is with this idea in view that 
the scale of the LeRoy-Dubois instrument is constructed. 
Physically, as before mentioned, this is an impossibility and 
cannot be accomplished. Others consider that it will invariably 
give both the axis, and entire amount of astigmatism of the eye. 
This it will do only in such cases where the astigmatism is con- 
fined to the anterior surface of the cornea ; but the astigmatism 
may not be confined to the cornea and therefore the lenticular 
astigmatism must be considered, as must also the fact that the 
posterior surface of the cornea may not be parallel with the 
anterior; if this be not so, it will influence the astigmatic 
refraction. 
In other words, ophthalmometers deal with the cornea only, 
and are therefore strictly speaking, keratometers, and any 
knowledge of other parts of the eye-ball that they may reveal 
to us, is obtained by a comparison of our other studies with 
those of the keratometer. 
In fact, all we obtain is a knowledge of the anterior surface 
of the cornea, its radii of refraction, its irregularities, and some 
idea of the transparency and nutrition of its superficial layers. 
When once this fact is thoroughly realized, there will be fewer Louis J. Lautenbach, A M., M.D., Ph. D. 
5 
disappointments, as well as fewer enthusiastic outbursts, than 
have up to this time characterized the progress of these studies. 
By means of the keratometer we can measure the corneal 
area, its curvature at any or all parts, and learn the angle of the 
axes of the principal meridians at the part under examination, 
as well as the difference between the radii of curvature at these, 
or any intermediate, points ; and can thus determine in diopters, 
the difference in corneal refraction at these points. 
In addition to this, the instrument has in my hands, proven 
valuable in determining problems as to the nutrition of the 
cornea, and as to increase or decrease of the intra-ocular 
pressure. 
My first keratometric work was done with a Helmholtz instru- 
ment, but I am now using the Javal instrument entirely, and 
with it have examined over eighteen hundred eyes of over nine 
hundred patients. 
In all cases of refractive errors or diseases of the eye-ball or 
its appendages (with the exception of a few cases of acute 
inflammation of the iris, cornea, and conjunctiva) in addition to 
the routine examination, a keratometric examination is in- 
variably made. Of these, over fourteen hundred eyes have 
been thoroughly examined and tested while under the influence 
of a mydriatic, either atropia or homatropia As a result of 
these examinations, I have found that the axis of astigmatism 
as determined by the keratometer, corresponded to the axis as 
determined by the mydriatic in eighty-eight per cent, of the 
cases, while the degree corresponded (after making the correc- 
tion of 0.37 diopters, subtracting it when the astigmatism is 
with the rule, and adding when against the rule) in forty-five 
per cent. 
It is an admitted fact that the astigmatism of a ball is not 
always confined to the- cornea ; that not infrequently it is 
lenticular. Of this we have two varieties-the static, and the 6 
Ophthalmometry. 
dynamic. In the dynamic variety, supposed by some to be a 
compensatory effort to overcome the effects of the corneal 
astigmatism, usually all that is necessary is to carefully correct 
the corneal astigmatism, the dynamic lenticular astigmatism 
disappearing In the static variety, the ophthalmometer cannot 
give us the the total astigmatism In these cases we must 
proceed to the estimation and correction of tbe lenticular 
astigmatism as well. It is these cases that, in the whole range 
of refaction work, give us the least satisfactory results. 
In the examination of corneae which have been subjected to 
weakening of structure in consequence, cither of local inflam- 
mations or systemic disorders-cases where the result obtained 
by glasses, while under mydriatic influence, are cither indifferent 
or nil, because of iriegularities in curvature or in the transpar- 
ency of the corneal layers-we can often get very good results 
through the aid of the keratometer. By instilling a few drops 
of castor oil on such corneae we are often enabled to get very 
clear itnages. and can thus determine the axes of the principal 
meridians and the difference in diopters between their refractive 
powers. 
The approach, advance, and subsidence of glaucoma has been 
made more noticeable and marked by the changes in the axis 
and the curvature of the cornea, and changes in the brilliancy 
of the keratometric images, than by any other method of 
examination. 
In developing myopia it will soon show the suspicious nature 
of the case, and in progressive malignant myopia, the changes 
are frequent and marked. I have often noticed that irritable 
retinae are associated with corneas whose axes and curvature 
vary, and now I always seek for the latter whenever I find the 
former. 
In corneal malnutrition, dependent upon syphilitic disease, the 
changing of the axes and curvatures, with a loss in the brillian- Louis J. Lautenbach, A.M., M.D., Ph. D. 
7 
cy of the reHex, precedes an inflammatory attack, and if this 
condition be appreciated serious results will often be avoided. 
In refracting cases of aphakia and in refracting shortly after 
injuries of the cornea and after operations involving the cornea, 
its value must be evident to all, giving us results which often 
we could not obtain without incurring possib'e danger from 
irritation and subsequent inflammatory action. 
Some of the intricate problems regarding the construction of 
the eye, its depth and diameters, its lens astigmatism and refrac- 
tion, can be determined by means of calculations from the data 
as furnished by this instrument as compared with those as 
furnished by the subjective examination under full mydriasis. 
Now briefly outlining, we find that the ophthalmometer will 
not give us the refraction, nor will it give us the total astig- 
matism except when this is confined to the cornea; or any 
knowledge as to whether there is or is not lenticular astigmatism. 
It will give us the axis and degree of astigmatism when this is 
corneal; practically we find that it gives us the axis in 88 per 
cent, and the amount of astigmatism in 45 per cent. It reveals 
to us a knowledge of diseased conditions of the eye-ball when 
the disease is of such nature as to interfere with the corneal nutri- 
tion or to increase or decrease the ocular tension. It will, in 
connection with other methods, allow us to calculate the lenticular 
refraction and astigmatism, as well as the depth of the eye-ball, 
and thus puts within our grasp a new method of the more 
thoroughly studying its function and anatomy. 
1723 Walnut St.