t with a macular choroidal atrophy and abnormal
pigmentation. She suffered, we afterwards concluded, from choroidal
tuberculosis. A recurrence involving adjoining choroid occurred fourteen
months ago. There was at the start pain, slight dilatation of the pupil,
and slight general hyperemia of the globe. The tension of the eyeball
rose to 60 mm., that of the fellow eye being 20 mm. Under miotics the
tension fell at first but slightly. It was 55 mm. at the end of a week;
but after two weeks came down to normal, 20 mm. A month later the
tension rose to 28 mm., but for a year has continued normal; the eye did
well under tuberculin treatment, and without any local treatment. In
September of this year I had two cases of iritis in which the
intra-ocular tension rose to 45 and 52 mm., respectively, and gradually
returned to normal, with the cure of the iritis under atropine. In one
of these cases, a lady of 70, I used atropine also in the other eye,
but the tension of that eye remained normal, 22 to 24 mm., throughout.
After needling the lens in young people I have seen a rise of
intra-ocular tension to 50 and 60 mm., maintained for many days, with
considerable general deep hyperemia, and soreness of the globe, followed
by gradual return to normal tension, and no permanent impairment of
vision or the visual field.

One other type may be mentioned. That of an elderly patient with marked
vascular disease, often renal involvement, and distinctly impaired
nutrition. There may be renal retinitis or retinal hemorrhages. The case
may easily become one of hemorrhagic glaucoma. It may run a very chronic
course. But it may become suddenly worse, or go on to complete blindness
with pain, demanding enucleation, after some temporary perturbation, as
the performance of a glaucoma operation. It is pre-eminently the kind of
a case you would prefer would go to some one else.

Each of these types illustrate a distinct cause or group of causes. The
first type brings us near to what may be the essential nature of
glaucoma, impairment of ocular nutrition by the intra-ocular tension,
which is generally elevated, but may not be above the usual normal. A
special weakness in the nutrition of nerve tissue may be assumed. It
would help to explain the cavernous atrophy of the optic nerve
associated with simple glaucoma. The second type shows impairment of the
regulative mechanism permitting rapid rise of the intra-ocular pressure.
In persons of good nerv