142 OPHTHALMOLOGY FOR VETERINARIANS 



rapidity of the cataractous formation. Drops of various 

 kinds have been placed upon the market which are 

 claimed to promote absorption, but, having been tried 

 by eminent men in the profession, they have been found 

 to have no value in this respect. After a cataract has 

 been formed there is no treatment except rehef by opera- 

 tion. 



Luxation of the Lens. — The lens becomes dislocated 

 by reason of traumatism, extreme muscular exertion, 



Cornea 

 Dislocated lens 



Cilia 



Fig. 31. — Vertical section of eyeball of horse, showing dislocated lens 

 in anterior chamber. Dotted line indicates normal position. 



sudden reduction of tension, extreme increase of ten- 

 sion, atrophy of the fibers of the zonule of Zinn, particu- 

 larly in hypermature cataract. In short, by stretching 

 or rupture of the suspensory ligament. 



In cases of partial luxation the border of the lens may 

 be tilted backward or forward. In complete luxation 

 the lens may be forced backward into the vitreous, and 

 in rare instances it is forced forward beneath the con- 



