AMAUROSIS 581 



other eye will become diseased ; but if it came on idiopathically, either 

 preceded by inflammation or otherwise, there is great risk of a repetition in 

 the sound eye. Nevertheless, instances are common enough of one eye 

 going blind from cataract, Avhile the other remains sound to the end of life ; 

 and those are still more frequent in which the one sound eye continues so 

 for six or seven years. 



AMAUROSIS 



This is a palsy of the nervous expansion called the retina, produced by 

 some disease, either functional or organic, of the optic nerve, Avhich is 

 generally beyond the I'cach of our senses, in examining it after death. 



The Symptoms are a full dilatation of the pupil, so that the iris is shrunk 

 to a thin band around it, and is so insensible to the stimulus of light, in con- 

 firmed cases, that, even when the eye is exposed to the direct rays of the 

 sun, it does not contract. In the early stages, this insensibility is only 

 partial ; and though there is such complete blindness that the horse cannot 

 distinguish the nature of surrounding objects, yet the pupil contracts 

 slightly, and the inexperienced examiner might pass the eye as a sound one. 

 The unnaturally large pupil, however, should always create suspicion ; and 

 when, on closing the lids and re-opening them in a strong light, there is 

 little or no variation in its size, the nature of the disease is at once made 

 apparent. 



The Treatment of amaurosis must depend upon the extent to which it 

 has gone, and its duration. If recent, bleeding and a seton in close 

 proximity to the diseased organ will be the most likely to restore it. 

 Sometimes the disease depends upon a disordered condition of the stomach, 

 and then a run at grass will be the most likely means to restore both the 

 affected organs to a sound state. Generally, however, an amaurotic eye in 

 the horse may be considered as a hopeless case. 



BUCK EYE 



A BUCK EYE is, strict!}^, rather a congenital malformation than a disease ; 

 but practically, in reference to the utility of the animal, it matters little. 

 It depends upon an access of convexity in the cornea, by which the focus 

 of the eye is shortened too much, the image being thus rendered indistinct 

 as it falls on the retina. No treatment can be of the slightest use. 



