1 From the Massachusetts Eye and Ear Infirmary (D.M.L.) and the Department of Ophthalmology, Harvard Medical School, Boston, MA; Jules Stein Eye Institute (D.G.K.), Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA; and New England Eye Center (M.G.) and the Department of Ophthalmology, Tufts University School of Medicine, Boston, MA.