Glaucoma | Page 2

measures, notably massage, vibration massage, suction
massage, electricity and diathermy.
(c) Indirect reduction of increased intra-ocular tension, brought about
by lowering the general vascular pressure.
(d) The relation of osmosis, lymphagogue activity, the absorption of
edema, the stimulation of capillary contractility, and the lowering of the
affinity of ocular colloids for water in their relation to the reduction of
increased intra-ocular tension.
DR. GEORGE EDMUND DE SCHWEINITZ, Philadelphia.
Discussion by DR. NELSON M. BLACK, Milwaukee.
IV. Trephining for Glaucoma.
Abstract:--
(a) The aim of the operation is the formation of a foreign-body-free
fistula.

(b) It is most important to leave uveal tissue untouched.
(c) Method of doing this explained.
(d) The area available for trephining.
(e) Method of increasing that area.
(f) Cornea splitting.
(g) Placing of trephine.
(h) Technique of using trephine.
(i) The operation is not difficult.
(j) The operation valuable as a prophylactic measure.
DR. ROBERT H. ELLIOT, F.R.C.S., Lieut.-Col. I.M.S., Madras, India.
Discussion by DR. FRANK C. TODD, Minneapolis.
V. Operations Other than Scleral Trephining for the Relief of
Glaucoma.
Abstract:--
Most of the ordinary surgical procedures employed for lowering
intra-ocular tension furnish a permanent cure of certain fairly well
defined varieties of glaucoma. They also relieve the symptoms and
retard the progress of other varieties of the disease, even if they do not
perform a cure. In a third class of cases, they either have no effect
whatever in arresting the disease or they hasten its march towards
blindness.
What operative procedure gives, on the whole, the best results? In other
words, what operation is the easiest of performance, is the least likely
to be attended by serious complications and is available for the largest
number of cases? Reasons for believing that of the better known

procedures simple iridectomy is the least effective, while those
interventions producing a large, thin, scleral filtration-cicatrix are the
most valuable.
DR. CASEY A. WOOD, Chicago.
Discussion by DR. A. E. BULSON, JR., Fort Wayne

Etiology and Classification of Glaucoma
BY
EDWARD JACKSON, M.D.,
Denver.
It is convenient to start with the conception that glaucoma is increased
tension of the eyeball, plus the causes and effects of such increase;
although a broad survey of the facts may reveal a clinical entity to be
called glaucoma, without increased tension constantly or necessarily
present, and cases of increased intra-ocular tension not to be classed as
glaucoma.
The physiologic tension of the eyeball is essential to ocular refraction,
and closely related to ocular nutrition. Fully to understand the
mechanism for its regulation would carry us far toward an
understanding of the causes of glaucoma. Normal tension is maintained
with a continuous flow of fluid into the eye and a corresponding
outflow. Complete interruption of the nutritional stream would be
speedy death; partial interruption may be held responsible for most of
the visual impairment and pain of glaucoma.
The balance of intra-ocular pressure is not maintained by the slight
distensibility of the sclero-corneal coat. Increased pressure does not
open new channels for the escape of intra-ocular fluid; if, indeed, it
does not tend to close the normal channels.

The affinity of the tissues for water, or, as Fischer explains it, the
affinity of the tissue colloids for water, seems too little related to the
requirements of ocular function to furnish the needed regulation of
tension. The lymph spaces and blood-channels of the eye are large, as
compared with the mass of its tissue colloids. In these spaces and
channels must be sought a means for rapid response to the need for
regulation of intra-ocular tension. Fischer has shown, that when the
enucleated eyeball is placed in a weak solution of hydrochloric acid,
the swelling of the tissue colloids is sufficient in a few hours, to burst
the sclero-corneal coat. But this is an eye in which all nutritional
changes have ceased. He brings together many facts to support the view
that in the living tissues impaired circulation, and especially diminished
oxidation, are the chief causes of increased affinity of the colloids for
water. Such affinity increased by the impairment of the intra-ocular
circulation, may well constitute a factor making for malignancy in
glaucoma. But it can hardly explain the original departure from a
normal pressure balance.
We must assume that intra-ocular pressure is kept down to the normal
limit, by the prompt response of a regulative mechanism, which
diminishes the flow of fluid into the eye, or permits its more rapid
escape, whenever fluid tends to accumulate in the eye and increase its
tension.
Little has been done to show that increase of fluid entering into the eye
is the cause of glaucoma. A normal, or even a low arterial blood
pressure is sufficiently above the normal intra-ocular pressure to
furnish a source of increased fluid in the eye. Increased arterial pressure
has been found in