I06 OPHTHALMOLOGY FOR VETERINARIANS 



of the globe are thin, and the pigment can be seen 

 through the sclera, giving it a bluish appearance. The 

 tension is increased, and when this subsides the dis- 

 ease ceases; but, if the tension continues, the disease goes 

 on to ultimate blindness. Both eyes are affected. It 



Fig. 24. — An extreme exophthalmos or protrusion of the globes, 

 more marked in the left, due to an abnormal fatty growth in the orbits. 

 Notice the opacity of the cornea from exposure. 



is said to be hereditary, though the exact nature and 

 cause of the disease is not fully understood. 



Opacities of the Cornea. — Opacities are the result of 

 ulceration or disease of the true corneal layer. They 

 may be small or large, thin or opaque, according to the 

 extent and depth of the disease. 



Opacities are usually divided into three degrees: 



