Peripheral iridectomy in closed-angle glaucoma.

PERIPHERAL iridectomy has become an accepted method of treating closedangle glaucoma. During the last 4 years we have performed this operation on more than seventy eyes and the results have convinced us that this is one of the safest and most successful of all operations for glaucoma provided that the cases are properly selected. It is the ideal operation for early cases of closed-angle glaucoma where the aqueous outflow has not become obstructed by goniosynechiae, but a detailed analysis of the first 39 cases shows a considerable number of successes in those in which the disease was more advanced, which indicates that this operation should not necessarily be confined to early cases but may sometimes have a place in the treatment of acute and "chronic"" congestive" glaucoma. We have also performed this operation as a prophylactic procedure on eyes with no positive evidence of glaucoma for reasons to be discussed later. To understand ho.w a peripheral iridectomy can control a closed-angle glaucoma (and thus appreciate the indications for the operation) we must have a clear picture of the sequence of events which causes the rise in ocular tension. This has been very clearly described by Barkan (1938, 1939, 1954), Chandler (1952), and other workers, and has been called the Curran Chandler mechanism. The essential feature is an abnormal relationship between the iris diaphragm and the lens. Priestley Smith (1891) first drew attention to the now wellrecognized fact that, in eyes with congestive glaucoma, the anterior chamber is shallow. The cause of this shallow anterior chamber may be congenital or developmental, associated with hypermetropia or due to an increase in the size of the lens, but whatever the reason the effect is that because the lens is further forward its contact with the iris diaphragm is more rigid so that these two structures can act as a valve hindering the easy flow of aqueous from the posterior to the anterior chamber, and thus causing an increase in pressure in the former. This increase in pressure causes the periphery of the iris to bulge forward (physiological iris bombe), especially when the pupil is semi-dilated and the