I40 OPHTHALMOLOGY FOR VETERINARL\NS 



plicated with pathologic changes in the chorioid and 

 retina. The lens during the second stage becomes 

 swollen because it has absorbed fluid, and the iris is 

 pushed forward in consequence, but not until the 

 striae reach the pupillary or, rather, central area, and the 

 lens assumes a bluish-white color and becomes partially 

 opaque, is vision disturbed to any great degree. 



A gradual mersion from the second to the third stage 

 takes place when the lens becomes totally opaque; the 

 excess of fluid is lost and it resumes its normal size. 

 During this stage there is no fundus reflex, the pupillary 

 area appears white and the vision is nil, though, if there 

 is no fundus disease, light may be perceived and also the 

 direction from which it comes. This is known as hght 

 perception and projection, which might be difficult to 

 obtain in the animal. The operation for cataract (ex- 

 traction) should be done during this stage. 



The fourth stage is indicated by a liquefaction of the 

 cortical portion of the cataract by reason of fatty de- 

 generation. 



The nucleus, however, retains its hardness, and 

 remains so for years, floating in the milky-like Hquid of 

 the remaining portion of the lens within its capsule. 

 In many cases the capsule itself sooner or later becomes 

 cataractous, and when this occurs an operation of ex- 

 traction is Hable to be attended with compHcations. 



A secondary or capsular cataract often occurs after 

 the extraction of the lens if an extraction is done 



