VETBKINAKY OPHTHALMOLOGY. 



91 



J'ersistans. During gestation tlie pupil is closed by a 

 membrane, and occasionally some part or all of it 

 remains. 



Fig. BO. 



Iridectomy. — (Excision of a portion of the iris ; re- 

 moval of the entire iris is iridavulsion.) Iridectomy 



Fig. Bl. 



•demands a speculum, fixation forceps, an angular or 

 straight keratome, or Grseffe knife, iris forceps and 



