4                                Verminous Ophthalmia in Equines

The intraocular pressure is often increased. These symptoms last for ten
to fourteen days and then clear up rapidly. When these symptoms have
cleared up, it may be difficult to detect any difference between the affected
and unaffected eyes.

Intermediary stage.—When the disease recurs, the same eye or its fellow
may be affected. Relapse occurs at intervals varying from a week to six
months. The symptoms exhibited in later attacks may not be so acute as
those in the initial attack, the lens gradually becomes more and more opaque.
Between two attacks, at a stage when the opacity of the lens is not very
appreciable, certain characteristic lesions such as small streaks or spots may
be noticed on the lens-capsule and their lesions are indicative of chronic eye
trouble.

Last stage.—After two or three attacks, the affected eyeball becomes
shrunken and appears to be smaller than the unaffected one. There is marked
wrinkling of the upper eyelid and in most cases the membrana nictitans pro-
trudes across the eyeball. In such chronic cases, the pupil is widely dilated
and the lens is opaque. A few cases have been seen when the pupil was
contracted and the iris was apparently closely adherent to the lens.

As a rule apparent recoveries, followed by relapses, occur, and three or
four such recurrent attacks cause permanent and complete blindness in the
affected animals.

It is only in about 4 per cent of cases that both eyes are affected simul-
taneously. Usually one eye is affected at a time and relapses occur after
apparent recovery. The other eye may be affected either in the intervals
or after the first eye has become blind. It also happens at times that one
eye remains unaffected throughout the course of the disease. In one interest-
ing case, one particular eye was repeatedly affected, the duration of the
affection extending over a long period, culminating in blindness in the one
eye. This eyeball was then removed for experimental purposes. Ten months
after this removal, the remaining eye which had remained normal and un-
affected, became affected with exactly the same symptoms and relapses.

No fever or other systemic disturbances have been observed to occur
in these animals ; but in the acute stages, an affected animal may suffer
from such a severe pain that it may not feed so well as it normally does.

The duration of the disease varies considerably in different individuals.
The acute stage lasts usually from 14 to 21 days. Relapses occur in from
1 to 6 months. Blindness ensues in these affected animals in a period vary-
ing from 6 to 18 months depending on the number and frequency of the
attacks.

                         INVESTIGATIONS CONDUCTED

Cultural examination of the tears collected during the acute stages of
the affection revealed a Diplococcus and a coliform organism only. These
organisms and the tears when instilled on healthy eyes of experimental horses