Glaucoma | Page 4

of the
disease. Zirm believes the venous plexus of the choroid is an essential
part of the mechanism for the regulation of intra-ocular tension, the
necessary vaso-motor control depending on nerve centers situated in
the iris.

Nerve Control
The accurate control of normal intra-ocular pressure, by mutual
adjustment of inflow and outflow of fluid, is scarcely conceivable
without some highly specialized, extremely sensitive nerve mechanism
to preside over it. This is suggested by analogy with the regulation of
secretion in the lacrimal, salivary, or peptic glands, or the maintenance
of blood pressure in the heart and arteries. Clinical observations point
the same way. Many patients connect their attacks (especially their
earlier ones of ocular discomfort, impaired vision, haloes around the
light, and dilated pupil) with social excitement, anxiety, worry, anger or
fatigue. A patient of mine gave up her card parties, because an exciting
game generally ended in blurred vision, a rainbow around the light, and
a dilated pupil, and sometimes an aching eye. Another woman
watching beside her dying husband and exposed to extreme cold, had
her first attack of glaucoma, so severe as to destroy the sight of one eye.
The other eye, also affected at the time, recovered good vision, and has
remained several years without a second attack and without treatment.
Laqueur's first attack occurred at the end of a long exhausting morning
in the operating room, with luncheon delayed two hours. The
connection of his later attacks with anger, worry, embarrassment, even
the excitement of watching a play at the theatre, was noted again and
again. In Javal's case, the attack fatal to one eye came at the
culmination of an exciting electoral campaign. The other eye was
stricken at the termination of the Dreyfus case, in which Javal was
intensely interested. There seems to be a special liability to glaucoma
among those residing at high altitudes, best explained by nerve
influence. The frequency of glaucoma among Jews may be due to a
small cornea, as suggested by Priestley Smith; but it is quite as
reasonable to connect it with a racial excitability or nervous instability.
More definite knowledge of the nervous mechanism concerned in the
regulation of intra-ocular pressure and the production of glaucoma is
much needed.
Alterations of Fluids and Tissues
The influence of increased affinity of the tissues for fluid has already

been referred to. That a similar obstacle to the escape of fluid from the
eyeball might be due to a change of character in the fluid, is a
conception that has been entertained as a working hypothesis, and
much experimental and analytical work has been done to test its
correctness. This work has been so slightly related to practical
ophthalmology, and so contradictory in its results that alterations in the
fluids can only be regarded as a possible etiologic factor. Glaucoma
secondary to intra-ocular hemorrhage, operations on the lens or its
capsule, or severe nutritional disturbance may be capable of such
explanation.
Different Kinds of Glaucoma
A better grasp of the etiology of glaucoma may be attained by
considering separately various types of cases; although perfectly typical
cases may be rare; and cases of mixed type and etiology much more
frequent.
Simple glaucoma has been recognized as closely related to atrophy of
the optic nerve with deep excavation. No line of demarcation can be
drawn between them, except by reserving the term of glaucoma for
cases that depart from the pure type, terminating in glaucoma of some
other kind, which is no more significant than the passage of a
conjunctivitis into a keratitis, or an iritis into a glaucoma. Cases of
simple glaucoma do run their course of many years to complete
blindness, or to death, without exacerbations, inflammation, or
characteristic pain. In such cases the intra-ocular tension does not rise
suddenly; and it may be little or not at all elevated above the usual
normal limit.
For nine years I have watched the progress of such a glaucoma in a
man now aged 87, with slow development of glaucomatous cupping of
the optic disc, now more than 3 D. deep. The tension has never been
noted at more than Plus T (?), and when taken with the tonometer
varied from 9 to 32 mm. for the worse eye, and 13 to 24 mm. for the
other. Similar cases in which the tension lay within the commonly
accepted normal limits have been reported recently by Bietti and Stock.

In the eye there is probably a normal equilibrium between blood
pressure, tissue activity, and intra-ocular tension. This may be
destroyed either by increasing the intra-ocular tension, or lowering the
tissue activity, or the blood pressure. Lowered blood pressure has been
suggested by Paton as an explanation of symptoms usually ascribed to
vascular obstruction. Rising blood pressure may be required in old age
to compensate