Laser Photocoagulation of Subfoveal Choroidal Neovascularization Secondary to Age-Related Macular Degeneration

Dr Yannuzzi's critique 1 of the Macular Photocoagulation Study (MPS) Group guidelines 2 for laser photocoagulation of subfoveal choroidal neovascularization in the April 1994 issue of theArchivesis balanced and informative and comes at a time when ophthalmologists are considering the management of agerelated macular degeneration with renewed interest. Omitted, however, was a consideration of the methods employed by the MPS Group in the subfoveal trials. I am concerned that the visual results from those studies could have been influenced by placebo response. Initial perusal of the MPS subfoveal photocoagulation reports does not suggest that a placebo effect, as described in the classic article by Beecher, 3 could have influenced the test results. After all, treated patients lost, on average, 3 lines of Snellen acuity immediately following the laser barrage. On reflection, however, such an effect could have become operative later on because the clinically significant visual results were