36 

 NEW GROWTHS ON THE CORNEA. 



Pterygium (see fig. 9) is a peculiar fleshy growth con- 

 sisting of an abnormal development from the conjunctiva. 

 It has been observed in horses, dogs and cattle. Its usual 

 situation is at the inner side of the eye ball; it is triangular, 

 or fan-shaped, with the apex extending almost to the center 

 of the cornea ; generally it is loosely attached to the cornea 



Fig. 9. 



Pterygium. — Fleshy growth on the conjunctiva and cornea (after 

 DeSchweinitz). 



and the conjunctiva. Sometimes it is present at birth and at 

 times it results from the repairing of an ulcer near the border 

 of the cornea. It is believed that animals exposed to smoke, 

 dust, heat and slight injuries to the cornea are predisposed 

 to its development. Treatment consists in removing the 

 loose pterygium with the knife or shears; this should be 

 done by a surgeon after the animal is cast or confined and a 

 solution of cocaine is applied to the eye. The cornea usually 

 remains opaque at the spot from which the tissue is removed. 

 When a pterygium results from the contracting scar tissue 

 pulling the conjunctiva over a part of the cornea, it should 

 be left undisturbed. 



A Dermoid is a small, skin-like growth, which usually ap- 

 pears on the nasal side of the eye ball, partly on the cornea 

 and partly on the conjunctiva. The outer surface is gener- 



