Equatorial cataract after corneoscleral trephining.

THE occurrence of cataract in association with glaucoma presents a therapeutic problem of some magnitude which has attracted a good deal of attention in recent years (Samuels, 1947; Sourdille, 1950; Chandler, 1949;, Fran9ois, 1947; Williamson-Noble, 1953). The difficulties of treatment are not made less by the uncertainty which still exists as to the role played by the glaucomatous process and its treatment in the genesis of the lens opacity. Since the utility of corfieo-scleral trephining was first established after its introduction by Elliot in the early 20th century, the cause of the cataract which may be seen post-operatively in some cases has been a subject of speculation. Elliot (1914) was not convinced that the cataract was due to the operative interference, and although, as experience with the operation has become world-wide, the contrary view has found its advocates, the general opinion appears still to be in agreement with his, provided that direct operative damage to the lens has not taken place (Duke-Elder, 1940; Spaeth, 1941; Arruga, 1952). The association of delayed reformation of the anterior chamber with post-trephine cataract is, however, generally familiar, and this post-operative complication has been assigned a major place in the causation of the lens opacity by Duke-Elder (1940) and by Williamson-Noble (1953). The purpose of this paper is to present four cases which showed lens changes after trephining, and in which the clinical features can be fairly clearly interpreted in the light of the gonioscopic picture of the site of the operation. This distinguishes them as a type of post-trephine cataract not previously described, and permits the formulation of a possible hypothesis to account for them.