Results of peripheral iridectomy in closed-angle glaucoma.

It is now generally recognized that the peripheral iris plays a major part in the mechanism of closed-angle glaucoma and consequently the practice of treating these cases by a peripheral iridectomy has become a standard procedure. In addition, many surgeons now adopt the policy of performing a prophylactic peripheral iridectomy on the other eye of a patient who has suffered an attack of angle-closure. Some are still reluctant to adopt as a routine procedure surgery on an eye with normal vision because of the risks involved, and this view may be encouraged by a recent publication (Phillips and Snow, I967) which suggests that the operation is not as safe as was once thought. The results we are to discuss later will, we hope, go some way towards alleviating these fears. But first it is necessary to review the evidence at our disposal to enable us to form a clear picture of the problem. It is an undisputed fact that an attack of acute closed-angle glaucoma, even if treated in the early stages (and unfortunately circumstances beyond the ophthalmologist's control often prevent this), may result in severe damage to the eye. Lowe (I965) stated that, despite the advances that have been made in the concepts of diagnosis and treatment in acute closed angle glaucoma, the disease still leaves a "trail of destruction in its wake". We also know that in a certain proportion of patients who develop acute glaucoma the fellow eye will sooner or later develop an acute angle-closure. Adams (I955) concluded that 54 per cent. will develop raised tension if an iridectomy is not performed. Kronfeld (I 956) stated that 50 per cent. will develop an acute attack within 5 years and Bain (I957), in a review of 200 cases, stated that in 53 per cent. of second eyes the attack occurred within 42 years. Lowe (i965) estimated that 75 per cent. of second eyes are at risk. These figures should convince anyone that the second eye must be treated either by miotics or by a peripheral iridectomy. Kronfeld (I956) and Bain (I957) both stated that the acute attack developed in spite of miotic therapy, and Lowe (I965) confirmed the inefficiency of miotic therapy. Blaxter and Chatterjee (I960) stated that they had been performing therapeutic and prophylactic peripheral iridectomies since I 956, a series involving over seventy cases. They reviewed the results of the first 39 cases and from these concluded that when this was performed on properly selected cases, it was a safe and worthwhile procedure. There were no significant operative or post-operative complications. Primrose (I960) described the results of peripheral iridectomy on 23 patients with closed-angle glaucoma which included twelve prophylactic operations and also concluded that this was a safe effective procedure. Lowe (I962) analysed the results of the "second eye" in 200 cases of acute closed-angle glaucoma of which 23 were bilateral, and of the remainder II 3 had medical treatment and