A truly statistical determination of the causes for operative failure in cases of retinal detachment in a very difficult task. For one reason, among many, a single series infrequently contains a sufficient number of cases that have been followed closely by the same examiners long enough to determine the eventual fortune (or misfortune) of the eye operated on. Many of us feel that if the retina is well in place four or five months postoperatively the procedure was successful, but most of us have seen an occasional patient who has suffered a recurrence up to a year or more postoperatively, and we may then secretly feel that in truth we did not "cure" this patient but instead neglected to provide adequate operative insurance for that eye's future. It is also rare that a series of patients with retinal detachment is not "selective" in one form or another. As an example,