Recent advances in vitreous microsurgical techniques described by Machemer, Charles, Hirose, Trese, de Juan, and others have resulted in successful anatomical reattachment of eyes with stage-5 retinopathy of prematurity (ROP). Such eyes had previously been classified as inoperable. Although nearly 50% of eyes achieve an anatomical reattachment of the posterior retina, from 10% to 30% of the reattached eyes reported to date have no light perception. Infants with stage-5 ROP in both eyes may be quite difficult to evaluate preoperatively, particularly with regard to visual function and the configuration of the retinal detachment. Protocols for obtaining a bright flash visually evoked potential (VEP) and standardized echography have been developed to determine the following: 1. Objective evidence of visual function in one or both eyes 2. The configuration and characteristics of the retinal detachment It is hoped that such prospective evaluation will help to identify those eyes with the best prognosis for both visual anatomical success.