The management of glaucoma in nanophthalmos

Patients with nanophthalmos are prone to develop a chronic painless type of glaucoma in middle age, probably due to the natural increase in the size of the lens which is already relatively too large for the small eye. Although the underlying mechanism is obscure, a slowly progressive "creeping" chronic angle-closure is postulated, but gonioscopic evaluation is difficult due to the shallow anterior chamber, with grade I and slit angles. Response to medical treatment is poor and miotics may even make the condition worse by producing relative pupillary block and by relaxing the lens zonule. Ordinary glaucoma surgery is to be avoided in nanophthalmos because of the fear of postoperative ciliary-block malignant glaucoma. Periopheral iridectomy performed in five eyes at an advanced stage of the chronic angle-closure did not facilitate glaucoma control in three eyes, and in two eyes in which the operation was combined with posterior sclerotomy, the eyes became blind from vitreous hemorrhage. Lenx extraction in five eyes controlled the glaucoma but was followed by choroidal effusion and nonrhegmatogenous retinal detachements in two eyes and blindness in another eye when combined with a posterior sclerotomy. No firm therapeutic recommendations can be made on the basis of the author's experience in the six reported cases. Conventional medical therapy seems ineffectual even when begun early in the glaucoma. Conventional glaucoma surgery must be performed early, before permanent damage to the outflow mechanism occurs but removal of the lens must be anticipated. The surgeon must also remain aware of the high incidence of serious posterior-segment complications which inexplicably follow glaucoma or lens surgery in nanophthalmos, as described by Brockhurst.