1. Johns Hopkins University School of Medicine; Wilmer Eye Institute; Baltimore Maryland USA
2. Johns Hopkins Bloomberg School of Public Health; Department of Health, Behavior and Society; Baltimore Maryland USA
3. Johns Hopkins Bloomberg School of Public Health; Department of Epidemiology; 615 N. Wolfe Street Baltimore Maryland USA 21205
4. Thomas Jefferson University; MidAtlantic Retina, The Retina Service of Wills Eye Hospital; Philadelphia Pennsylvania USA
5. Associated Retinal Consultants; Phoenix Arizona USA
6. National Institutes of Health Library; 10 Center Drive Room 1L09G MSC 1150 Bethesda Maryland USA 20892
7. University Hospitals Eye Institute/Case Western Reserve University; University Hospitals Eye Institute; 11100 Euclid Avenue, Lakeside 4107 Cleveland Ohio USA 44106