YETEEIlsrARY OPHTHALMOLOGY. 73 



tion. If an ulcer extend deep enough to reach the 

 membrane of Descemet, it may bulge forward through 

 the ulcer like a vesicle, and thus form a hernia of the 

 cornea or heratocele^ and is usually followed by per- 

 foration. Larger ulcers generally lead to staphyloma. 

 When perforation does occur, there is escape of the 

 aqueous and a carrying forward of the iris and lens. 

 If the iris becomes fast into the Avound, it forms an 

 anterior synechia. If perforation is lai'ge enough, the 

 iris may ijrotrxide^ becoming adherent around the 

 edges, leaving synechia. Sometimes, after healing of 

 the ulcer, there will be re-accumulation of aqueous and 

 tearing loose of the adhesions through the action of 

 the pupillary muscles, the iris then assuming its free- 

 dom, floating in the aqueous. As before mentioned, 

 the lens may also be carried forward against the per- 

 foration, and if it return to its position we may see 

 some matter deposited on its anterior capsule, thus 

 constituting anterior capsular cataract. Remember 

 that adhesions sometimes formed may never be broken, 

 and the anterior chamber may be never re-established. 

 If the aperture, resulting from ulcer and sloughing, 

 be extensive enough to allow of escape of all the 

 contents of the eye, atrophy of the globe will result. 

 The rule in healing of ulcers is that some trace 

 be left, from a slight cloud to a dense opacity, and 

 are variously termed, according to degree — nubecula^ 

 a mist ; nebula^ a cloud ; macula^ a spot. And 



