1. Moorfields Eye Hospital NHS Foundation Trust; 162 City Road London UK EC1V 2PD
2. Bascom Palmer Eye Institute; Miami Florida USA 33136
3. Johns Hopkins Bloomberg School of Public Health; Department of Epidemiology; 615 North Wolfe Street, W5010 Baltimore Maryland USA 21205
4. Warren Alpert Medical School of Brown University; Division of Ophthalmology; Providence Rhode Island USA 02908