Trapdoor diathermy beneath the exudative mounds of peripheral uveitis reduced the inflammation. Five eyes were operated on because of secondary glaucoma and were controlled by diathermy and medical therapy. One eye with detachment was reattached, and the exudative mass regressed. The exudative masses may disappear for years following the diathermy. No surgical complications were encountered. Unilateral operations of the most severely involved eye, in cases of bilateral disease, resulted in the operated eye being quieter than the unoperated eye. Posterior pole edema and glaucoma frequently occurred in these cases. Applanation pressures were significantly higher than Schiøtz. Peripheral uveitis is common and should be suspected in cases of cyclitis without a posterior chorioretinal scar. When steroids produce side effects or fail to control the inflammation of peripheral uveitis, antimetabolites (ie, cyclophosphamide) have proven effective.