CHAPTER IV. 



DISEASES OF THE CORNEA. 



Examination.— The cornea is normally transparent forming 

 the anterior covering of the eyeball. It is shaped somewhat 

 like a watch-crystal and in the dog, cat and bird spherical in 

 form. The surface is smooth and shiny. In examining the 

 cornea employ either daylight or artificial light. The animal 

 may be restrained with an anesthetic or hoppled and tape 

 applied around the mouth. By everting the eyelids with 

 the thumb and index finger the entire cornea is exposed. Its 

 form should be noted, its curvature and its transparency. 

 The curvature of the cornea of one eye should be compared 

 with that of the other. Of assistance in this regard is a 

 lighted candle. By noting the size of the flame as reflected 

 by the cornea of each eye, comparisons may be made. If 

 the curvature is weak, the flame appears larger; if strong, 

 smaller. In dogs and cats physiological variations will be 

 noted in the curvature of each cornea due to the difference 

 in the shape and size of the eyes. The surface of the cornea 

 should be smooth and even. To determine these observe it 

 from the side, best using reflected light. The cornea should 

 be tested for sensitiveness by gently touching it. It is 

 normally very sensitive. In ulceration and when inflamed 

 sensitiveness is increased; it is reduced in glaucoma. Further 

 examination is made for cuts, scratches, foreign bodies, etc. 



KERATITIS. 



Definition.— An inflammation of the cornea. Two types 

 are recognized: 1. Non-suppurative, and 2, suppurative 

 keratitis. Under the former are included the following 

 forms: (a) Superficial, (b) vascular (pannus), (c) keratitis 

 pigmentosa, (d) keratitis punctata superficialis, ie) parenchy- 



