1. Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
2. Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland
3. The MIND Center, University of Mississippi Medical Center, Jackson
4. Department of Epidemiology, University of Colorado, Anschutz Medical Campus, Denver
5. Department of Ophthalmology, University of Colorado, Anschutz Medical Campus, Denver