1. Johns Hopkins University School of Medicine; Wilmer Eye Institute; 600 North Wolfe Street Wilmer B-43 Baltimore Maryland USA 21287
2. Massachusetts Eye and Ear Infirmary; 243 Charles St, Connecting Building 703 Boston Massachusetts USA 02114
3. University of Rochester School of Medicine; Flaum Eye Institute; 601 Elmwood Avenue Rochester New York USA
4. University of Nebraska Medical Center; Stanley M. Truhlsen Eye Institute; 985540 Nebraska Medical Center Omaha Nebraska USA 68198