EXOPHTHALMOS.
This consists in an increase of the media of the eye so as to cause an excessive increase in size, and an unsightly bulging outward from the orbit and between the lids. It may be said to be a more exaggerated enlargement of the eye ball, than has been already noticed under glaucoma.
It has been seen in nearly all classes of domestic animals. Everhardt and Möller reports it in horses, Hausmann, Pradal, etc., in cattle, LaNotte, in lambs, Cöster, Trasbot, etc., in dogs, and Trasbot, in birds (chickens and parrots). It has been found congenitally in lambs and at a few days old in foals, especially when weak and puny; in older animals it appears to be most frequent in the anæmic or starved animal, in the lymphatic, or, as in man, in the goitrous.
The manifest projection outward of the eye may occur as a nervous phenomenon, without intraocular pressure, and without abscess, neoplasm, or inflammation in the depth of the orbit. In a case of tuberculosis in a three year old cow, I have found this condition, with normal tension of the eyeball, but with acute tubercular meningitis of the pia, surrounding the pons and crura cerebri, a grayish exudate with lighter miliary centres, and a considerable clot of extravasated blood.
Symptoms. Mostly without any febrile reaction, there is a manifest enlargement and bulging of the globe of the eye, so that it stands out between the lids which can no longer cover it. The cornea, aqueous, lens, and vitreous are not usually opaque, but show only a pale, blue, opalescent tint. The pupil is often widely dilated so as to show clearly the interior of the eye. Vertiginous symptoms have been observed in the cow (Pradal), the supposed result of intraocular pressure.
Treatment has had little effect when it stops short of puncture of the cornea or iridectomy.