1. Department of Ophthalmology, Medical University Graz, 8036 Graz, Austria
2. Department of Dentistry and Oral Health, Medical University Graz, 8036 Graz, Austria
3. Institute for Medical Informatics, Statistics and Documentation, Medical University Graz, 8036 Graz, Austria
4. Department of Ophthalmology, Sanatorium Hera, 1090 Vienna, Austria