222 THE HORSE 



It is a very hopeless disease to treat, and whatever 

 repair takes place is mainly due to the efforts of Nature, 

 and not to any medicinal value of topical applications. 

 As previously stated, cataract is incurable ; renders a 

 horse unsound, but not necessarily less useful for certain 

 purposes, provided that only one eye is implicated. 

 Sometimes, however, both are affected. Cataract may 

 be partial or complete, in accordance with the stage at 

 which the disease has arrived. Its detection is a matter 

 for an expert and requires the use of the ophthalmoscope 

 for critical inspection. But, under ordinary circumstances 

 cataract can be seen as a greenish discoloured area 

 towards the back of the eye, more especially when the 

 pupil is dilated, which happens when the eye is shaded. 



There are many other affections of the eye, such as 

 amaurosis, or glass-eye, a disease characterised by the 

 eyes being apparently healthy yet the animal is 

 blind. This is not a common affliction, although it is by 

 no means infrequently met with, and results from 

 variable causes, such as excessive haemorrhage and 

 pressure upon the optic nerve through injury, abnormal 

 growths, etc. 



Amongst other diseases of the eye mention must be 

 made of glaucoma, an evertion and inversion of the 

 eyehds, warty growths on the eyehds, parasites of the eye, 

 luxation or displacement of the eyeball, and tumours of 

 the orbit, all of which produce impairment of sight and 

 other symptoms, associated with the particular part 

 involved. 



Before concluding this chapter it is worthy of remark 

 in passing that the most severe injuries to the eye are 

 often followed by almost complete recovery of the eyes 

 to its normal state, indicating what remarkable repara- 

 tive power is inherent in these organs. 



