1. Department of Medicine, Surgery and Pharmacy, University of Sassari, 07100 Sassari, Italy
2. Ophthalmology Unit, Azienda Ospedaliero-Universitaria di Sassari, 07100 Sassari, Italy
3. Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy
4. Eye Clinic Section, Department of Surgical Sciences, University of Turin, 10126 Turin, Italy