1. First Division of Ophthalmology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece
2. Jules Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
3. Department of Opthalmology, University Hospital of Heraklion, Heraklion, Crete, Greece
4. Vardinoyiannion Eye Institute of Crete, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
5. Department of Social Medicine, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece