1. Fondazione G.B. Bietti per lo studio e la ricerca in Oftalmolologia-IRCCS; Ophthalmology; Via Livenza n 3 Rome Italy 00198
2. Wilmer Eye Institute, Johns Hopkins University School of Medicine; Department of Ophthalmology; Baltimore Maryland USA
3. Johns Hopkins Bloomberg School of Public Health; Department of Epidemiology; 615 North Wolfe Street, Mail Room E6132 Baltimore Maryland USA 21205