1. Department of Epidemiology, the Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland;
2. Department of Ophthalmology, the Wilmer Eye Institute, the Johns Hopkins University School of Medicine, Baltimore, Maryland; and
3. Department of Ophthalmology, the New York Eye and Ear Infirmary of Mount Sinai, the Icahn School of Medicine at Mount Sinai, New York, New York.