Between 1975 and 1983 the authors saw 5 patients (average age 52) with massive unilateral episcleral vascular congestion and secondary open-angle glaucoma. All of the patients were found to have a quite large, asymmetrical cupping of the optic disk and 3 of them had glaucomatous scotomata. There was no exophthalmos, no motility disturbances and no evidence of intracranial circulation problems. Sinosotomy was performed initially in all the patients, resulting in normalization of pressure in 3 cases; normalization was also achieved in the fourth patient with additional drug therapy. Compensation was achieved in the fifth patient following goniotrepanation. The cause of the episcleral vascular disturbance is still unknown.