The authors performed a retrospective analysis on 296 phakic patients who had bilateral lattice degeneration and a retinal detachment in one eye. The analysis was done to determine the complications of full prophylactic treatment to lattice and breaks in the fellow eye and to explain the reasons that this treatment sometimes did not prevent new retinal breaks or detachments. The patients were followed for a mean +/- SD of 7.415 +/- 5.422 years after their first detachment. Twenty-four new tears occurred in the fellow eyes during this time, seven (29.2%) of which were away from areas of visible lattice. Prophylactic treatment did not appear to cause new tears or increase the risk of detachment if a new tear occurred. It also did not compromise the surgical repair in those patients who had eyes in which new breaks or detachments developed. The risk of visual loss was similar in those patients receiving prophylactic treatment compared with those not receiving treatment.