CHRONIC KERATITIS.
Sequel of trichiasis, entropion, eczema, etc. Age. Symptoms: moderate, lids partly closed, cilia matted together, crusted, cornea clouded, dull, with ramifying vessels. Resolution. Fibroid degeneration, permanent opacity. Treatment: tonic regimen, outdoor exercise, iron, bitters, calcium sulphide, astringent antiseptic collyria, atropia, mercury oxide.
This is especially common in dogs in warm latitudes. Trichiasis and entropion are perhaps the most common of the direct causes. Eczema and other skin eruptions affecting the lids are additional causes, while old and debilitated dogs are especially subject to the affection. It is less frequent in horses.
The symptoms are much less severe than in the acute form. The lids are usually partially but rarely completely closed, lachrymation may be absent and is never excessive, the secretion usually sticks together the cilia and lids, and always forms crusts on them, the palpebræ are less sensitive than in acute keratitis, the cornea is habitually clouded of a bluish-white color, yet in the main partially transparent and without the disc opacities of the acute type of disease, and the pupil, which is usually visible in a good light or under oblique illumination, may be slightly but is not excessively contracted. The surface of the cornea seems to have lost some of its polish, and in its substance blood vessels can usually be made out.
Under favorable conditions these cases may end in resolution and especially under a change of food and environment. In less fortunate cases they result in a fibroid degeneration of the cornea and deep permanent opacity.
Treatment. It is usually desirable to change the regimen so as to improve the general health, and to allow a fair amount of outdoor exercise. In the very old and debilitated the case is rather hopeless. A course of iron or bitters will sometimes have a good effect. In other cases sulphide of calcium â…’ grain thrice a day will prove useful. Eczema must be treated secundum artem.
Locally astringent and antiseptic collyria may be used as in the acute form. Atropia, 5 grs. to the oz., is a valuable adjuvant, to be instilled in drops. Ointment of yellow oxide of mercury, a piece like a pin head rubbed inside the lids once or twice a day often acts well. Finally Trasbot strongly commends liquor of Van Swieten.