358 DISEASES OF THE EYES. 



DISEASES OP THE SCLEROTIC COAT OF THE BYE. 



Inflammation of the Sclerotic Coat. 

 (Keratitis.) 



Notwithstanding the fact that the sclerotic coat does not contain 

 any bloodvessels, it is frequently the seat of inflammatory pro- 

 cesses which become present through a pericorneal injection due 

 to intense irritation of the bloodvessels which surround the border 

 of the sclerotic coat, and further by an opacity of the cornea form- 

 ing an obstruction that prevents the admission of rays of light into 

 the eye itself. This clouding or opacity may extend over the 

 entire sclerotic coat, or it may only involve a small portion. It 

 varies in color from a grayish-blue to a pure gray. It is yellowish- 

 gray in some cases, but never pure white in coloration (cicatricial 

 dulness). On careful examination it seems to be difEuse, forming 

 spots or stripes. The lustre of the membrane is dull on its surface 

 and a partial loss of the epithelium is noticed. The other symp- 

 toms are avoidance of light, convulsive movements of the eyelids, 

 and discharge of thin water from the corner of the eyelids, visual 

 deficiencies, and in some cases the animal may be partially or even 

 totally blind. This is especially seen when the opacity of the 

 sclerotic membrane is in the region of the visual line that is 

 opposite the pupil. 



Pathological Anatomy. "We have in other cases of keratitis 

 the appearance of large quantities of round cells in the sclerotic 

 membrane. These come from the bloodvessels of the neighboring 

 membranes and conjunctiva. These are wandering cells which 

 find their way into the sclerotic coat. As long as the round cells 

 in the sclerotic membrane are not crowded together it remains 

 unaltered in its true structure (infiltration of the sclerotic mem- 

 brane), and complete recovery follows after the cells have disap- 

 peared. But as soon as the cells are packed too closely together 

 the sclerotic tissue is partially destroyed by maceration and 

 necrosis, followed by a loss of actual substance. If this is sur- 

 rounded by intact tissue of the sclerotic membrane, it forms an 

 abscess; if it is open externally, it is an ulcer. We consider us 

 ulcers small superficial openings in the cornea which are always 

 round in the early stages, and are caused by infiltrations located 



