1. Department of Surgery and Physiology, Ophthalmology Unit, Faculty of Medicine of University of Porto, Porto, Portugal
2. Service of Ophthalmology, Hospital S. João, Al. Professor Hernâni Monteiro, 4200-319 Porto, Portugal
3. Department of Biomedicine, Anatomy Unit, Faculty of Medicine of University of Porto, Al. Professor Hernâni Monteiro, 4200-319 Porto, Portugal
4. Center for Health Technology and Services Research (CINTESIS), Faculty of Medicine, University of Porto, Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal