420 



DISEASES OF THE EYES 



anterior chamber. After liaving prepared the dog as in the operation 

 for discission, an assistant holding the eyelids apart, with another 

 forceps seize the conjunctiva of the eyeball in the neighborhood 

 of the median line of the eyeball, at the same time everting the upper 

 eyelid. We then make an incision by means of Graefe's cataract knife 

 (Fig. 143, b), about 5 mm. broad, through the cornea, about 2 or 3 mm. 

 from the border of the sclerotic membrane. We then pass a discission 

 needle through the wound, split open the lenticular capsule, as in discis- 

 sion, and empty the soft parts of the cataract by means of Daviel's 

 spoon (Fig. 143, c). Any remnants of the cut capsule which may not 

 be removed at the time are left to be reabsorbed. If during the operation 

 Ave observe prolapsus of the iris, we must try to restore it to its position 



' ■%//#fMii;m'# 



Fig. 145. — Lobular extraction of leii.s. {Cadiot and Breton.) 



by means of Daviel's spoon (Fig. 143, c). If this is not possible, we 

 may cut it off close to the wound of the cornea. 



It is very evident that linear extraction is only to be performed in 

 cases of complete softening of the lens. This may be recognized liy 

 total opacity of the lens and alteration of the iris, and also when the 

 anterior ca])sule is pushed toward the cornea. 



Lobular Extraction. — Lobular extraction is indicated in hard cata- 

 ract, which is generally senile, where the lens may be prolapsed into the 

 anterior chamber and where discission will only produce an imperfect 

 result — that is to say, where reabsorption of the lens does not progress 

 properly. It is performed in the following manner: 



Make an incision into the cornea exactly as in linear extraction, by 

 means of Graefe's cataract knife, but it must be enlarged to 8 or 10 mm, 

 (Fig. 145). After that the capsule of the lens is split by the discission 

 needle, the fluid of the anterior chamber is allowed to escape, and at the 



