1. Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University of Tübingen, Elfriede-Aulhorn-Str. 7, Tübingen 72076, Germany
2. Department of Ophthalmology, Trakia University, Stara Zagora, Bulgaria
3. Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University of Tübingen, Tübingen, Germany