1. Department of Ophthalmology, Jagiellonian University Collegium Medicum, 38 Kopernika Str., 31-501 Krakow, Poland
2. Ophthalmology and Ophthalmic Oncology Clinic, University Hospital, 38 Kopernika Str., 31-501 Krakow, Poland
3. Institute of Optics and Optometry, University of Social Science, 121 Gdanska Str., 90-519 Lodz, Poland
4. Provisus Eye Clinic, 112 Redzinska Str., 42-209 Czestochowa, Poland
5. Department of Statistics, State University of Applied Science in Konin, 1 Przyjazni Str., 65-510 Konin, Poland