1. From the Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, and the 2Department of Epidemiology, University of Michigan, Ann Arbor, Michigan; and
2. From the Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, and
3. From the Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, and the 3Eye Center, University of Pittsburgh, Pittsburgh, Pennsylvania.