1. Faculty of Medicine, The University of Jordan; Department of Special Surgery-Ophthalmology; P.O. Box 13046 Amman Jordan
2. Kaiser Permanente Largo Medical Center; 1221 Mercantile Lane Largo Maryland USA 20774
3. Johns Hopkins Bloomberg School of Public Health; Department of Epidemiology; Room W6138 615 N. Wolfe St. Baltimore Maryland USA 21205
4. Johns Hopkins University School of Medicine; Wilmer Eye Institute; 600 N. Wolfe Street Maumenee, 7th floor Baltimore Maryland USA 21287