OPERATIONS FOR CATARACT 145 



occur, this operation may be repeated; in fact, several 

 operations may be necessary to produce complete ab- 

 sorption. 



In some cases following discission swelling of the 

 lens takes place, which causes pressure upon the anterior 

 drainage canal (canal of Schlemm), producing an in- 

 creased tension, often accompanied with much pain. 

 If this persists after the use of ice-cold applications and 

 rest, it may be necessary to make an incision of the 

 cornea at its margin and allow the lens substance to 

 escape. In severe cases of increased tension an iridec- 

 tomy may be performed. Iritis of a severe type may be 

 produced by irritation from floating particles of the 

 lens. This must be met by the use of atropin and hot 

 appHcations locally, purgatives, rest, and a dark stall. 



Extraction of Cataract. — This operation is adapted 

 for all hard cataracts, and for such as a discission would 

 be deemed inadvisable. 



Before attempting this operation, however, there are 

 many things to consider. Should the fundus be dis- 

 eased or the optic nerve atrophied, the operation would 

 be of no practical value. To determine whether the 

 fundus is normal the animal should be placed in a dark- 

 ened room, the better eye covered, and light from a 

 small mirror reflected on the eye being tested. Note the 

 action of the pupil, and whether the animal notices the 

 light as it is placed at various points of the fields — above, 

 below, outward, and inward. If the pupil reacts, and 

 10 



