1. Department of Ophthalmology, Medical University of Graz, Graz, Austria;
2. Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria;
3. Division of General Otorhinolaryngology Head and Neck Surgery, Medical University of Graz, Graz, Austria;
4. Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria