Co-investiagtors in this study are participating in a multicenter randomized trial to assess the effectiveness of laser photocoagulation in preventing of delaying severe visual loss in age-related macular degeneration (AMD) complicated by a subfoveal neovascular membrane. As members of a participating clinical center, the co-investigators anticipate 100 eligible patients each year with new subfoveal membranes will be randomly assigned to treatment/no treatment groups. Approximately 50 patients per year will be enrolled with recurrent neovascular membranes. The purpose of this ancillary study to the Foveal Photocoagulation Study (FPS) is to utilize the pattern electroretinogram as an objective, readily-quantifiable measure of macular function in these patients. PERGs will be obtained from each patient at the time of enrollment, at 3 and 6 months following enrollment, and every 6 months thereafter for the duration of the FPS study. Seven check sizes, corresponding to spatial frequencies ranging from 0.05 to 3.0 cycles per degree, will be presented at pattern reversal rates of 2 Hz and 30 Hz. Progression of macular degeneration over time will be assessed in each group of patients by determining the parameters of functions relating PERG ampitude to spatial frequency. Since each patient must have visual acuity in the study eye no better than 20/80 and no worse than 20/320 to be eligible for the trail, supplementary measures of macular function are needed to help assess treatment efficacy. Preliminary work has shown that PERG function provides an objective measure of "retinal acuity", relates to quality of vision, is readily measurable in patients with low vision, and has low intervisit variability. It is anticipated that this approach will be of value not only in the assessment of treatment efficacy within the context of the FPS trial, but also will be of value in future treatment trials in patients with AMD.