VITREOUS detachment is a constant accompaniment and thus a cardinal symptom of retinal detachment, the importance of which is being increasingly stressed by modern authors. It has been indicted as one of the causes of retinal detachment, its action being enhanced by vitreo-retinal adhesions, congenital or acquired. It is less known that all aphakic eyes show some degree of vitreous detachment, a fact first mentioned by Heinz (1944) in a report to the Ophthalmological Society of Vienna (Hruby, 1950). Cataract extraction with the aid of alpha-chymotrypsin has since become a common practice, and we wished also to investigate whether the use of this enzyme affects the incidence of vitreous detachment in aphakic eyes. To ascertain whether the vitreous detachment bore any relationship to the aphakia, we compared phakic eyes in persons of the same age group as our patients.