1. Department of Epidemiology and Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States 2University of North Dakota, School of Medicine and Health Sciences, Grand Forks, North Dakota, United States
2. Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States 4Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
3. Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States