Laser prophylaxis for age-related macular degeneration

Background: Age-related macular degeneration (AMD) is the most common cause of severe and irreversible vision loss among people 50 years of age or older in many Western countries. Most of the available treatments for AMD are intended for the late stage, specifically for choroidal neovascularization (CNV). Effective preventive treatments could have an even greater impact on the vision of the millions of people at risk for vision loss from AMD. Drusen are typically the earliest lesions seen in patients with AMD and precede the development of CNV. In 1973, Gass noted the disappearance of drusen in eyes that received laser photocoagulation, which led to the hypothesis that laser-induced drusen reduction could alter the natural course of AMD. Methods: We reviewed relevant articles found through a search of MEDLINE through February 2005 by means of the following key words, alone or in combination: drusen, laser, photocoagulation, age-related macular degeneration, macula and choroidal neovascularization. Results: Reports ranging from individual cases and case series to randomized controlled pilot studies have described various laser treatment protocols and their effects on eyes with high-risk drusen but no neovascular changes. These reports provide evidence that laser photocoagulation can induce drusen reduction. Although some investigators have reported a corresponding improvement in visual function, others have found no change or even worsening. The results in several of the larger randomized controlled studies suggest that CNV may occur at an increased rate in laser-treated eyes with high-risk drusen in patients who have neovascular AMD in the other eye. The long-term effects of laser treatment in patients with high-risk drusen in both eyes and no neovascular changes have yet to be determined. Interpretation: The outcome of clinical trials such as the Prophylactic Treatment of Age-Related Macular Degeneration and the Complications of Age-Related Macular Degeneration Prevention Trial will help to determine the role of laser prophylaxis in patients with AMD.