Laser photocoagulation of subfoveal neovascular lesions of age-related macular degeneration. Updated findings from two clinical trials. Macular Photocoagulation Study Group.

To report 3- and 4-year visual outcomes in eyes followed up in two randomized clinical trials of laser photocoagulation for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration. Eyes of consenting patients were assigned randomly to laser treatment or no treatment. Visual acuity, reading speed, and contrast threshold were measured before random assignment, 3 and 6 months later, and at 6-month intervals thereafter. Visual acuities of treated and untreated eyes were compared 4 years after enrollment, in the Subfoveal New CNV Study (eyes without prior laser treatment), and 3 years after enrollment, in the Subfoveal Recurrent CNV Study (eyes with subfoveal recurrent CNV at the periphery of an earlier laser treatment scar). Four years after enrollment in the Subfoveal New CNV Study, 39 (47%) of 83 untreated eyes and 17 (22%) of 77 laser-treated eyes had lost 6 or more lines of visual acuity from baseline levels (P = .002). At the 3-year examination in the Subfoveal Recurrent CNV Study, 21 (36%) of 58 untreated eyes and six (12%) of 49 treated eyes had lost 6 or more lines of visual acuity from baseline levels (P = .009). Comparisons based on contrast threshold and reading speed for enlarged text also favored laser treatment in both trials. Stronger evidence favoring laser photocoagulation of subfoveal CNV has been provided by continued follow-up of patients enrolled in these two clinical trials. The benefits of laser treatment have persisted through at least 4 years of follow-up in the Subfoveal New CNV Study and 3 years of follow-up in the Subfoveal Recurrent CNV Study.