ALBINISM. WATCH EYE.
The albino is an animal in which there is a complete absence of pigment in the eye. It is usually seen in white races of rats, rabbits and dogs, and both the iris and choroid reflect a pink tint. It may cause photophobia and some weakness of vision but, in the main, it seems to be harmless to the lower animals. In horses it is occasionally seen as a partial defect, a portion only of the iris and adjacent sclerotic appearing of a brilliant white color. It does not usually seem to impair the vision, so that at the worst, it is only looked on as a blemish. It is needless to attempt a remedy.
PERSISTENT PUPILLARY MEMBRANE.
The persistence of this embryonic membrane has been noticed in the horse (Schindelka), ox (Meyer), rabbit (Mayerhausen), and dog (Möller). It tends to disappear with the growth of the animal and rarely does any perceptible harm.
OCCLUDED PUPIL.
This has been frequently found in horses as a sequel of iritis, and permanent adhesion of the contracted iris to the front of the lens capsule. It is in short, a posterior synechia with closure of the pupil. The lens and its capsule are usually opaque so that there would be no gain in detachment of the iris. If, however, there is reason to conclude that any part of the lens is still transparent, the performance of iridectomy over this portion, would produce a new aperture for the entrance of light.
CYCLITIS.
This is described by Möller as occurring in the domestic animals, but he fails to furnish instances of its diagnosis during life, and it is not likely to be often recognized in the living animal. Beside the usual signs of iritis, there is extreme tenderness to pressure around the anterior border of the sclera, increase of intraocular pressure, followed later by its diminution, and a cloudiness of the anterior portion of the vitreous humor. This last condition can only be detected by a full illumination of the vitreous, and its examination with the ophthalmoscope. It is quite liable to be complicated by suppuration and to go on to panophthalmitis.
The treatment does not materially differ from that of iritis, yet atropia must be used with caution as it is liable to increase the suffering. The preparations of mercury have been especially recommended.