Analysis of 196 patients with retinal dialysis indicated that unilateral nasal and superior dialyses almost invariably were produced by trauma (87.5%). A traumatic cause is proposed for unilateral inferotemporal dialyses, which also had an inordinately high rate of trauma (56%). Bilateral retinal dialyses, making up 14% of all cases, had a much lower incidence of trauma. A nongenetic, developmental anomaly at the ora serrata may account for some bilateral cases. In all types of dialyses, women acknowledged trauma less frequently than men, which probably reflects a sociologic tendency for women to deny physical abuse. Twelve percent of dialysis patients had ocular hypertension exceeding 22 mm Hg and 16% had angle recessions. Successful detachment surgery normalized the intraocular pressure in most cases without additional filtering surgery or medications.