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

Abstract

Objective: 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.

Design and main outcome measures: 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).

Results: 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.

Conclusions: 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.