Retinoschisis was discovered in 102 eyes of 56 patients, revealing an incidence of 3.7% for the total group and 7% for the group 40 years of age and older. It was bilateral in 82%, and the area of maximal involvement was the inferior temporal quadrant in 72%. It extended posterior to the equator in 43% of the patients. Retinoschisis was significantly associated with hyperopia, as compared to the total population studied. Retinal breaks were found in 8% of the group, but they were found in both layers in only one patient. Because the number of patients in which retinoschisis leads to retinal detachment is extremely low, and because posterior extension is very slow and probably rarely extends to the macula, treatment should be used only very infrequently.