1. From the Carver Family Center for Macular Degeneration, Department of Ophthalmology and Visual Science, The University of Iowa Carver College of Medicine, Iowa City, Iowa; and the
2. From the Carver Family Center for Macular Degeneration, Department of Ophthalmology and Visual Science, The University of Iowa Carver College of Medicine, Iowa City, Iowa; and the2Howard Hughes Medical Institute, Chevy Chase, Maryland.