1. Department of Ophthalmology, Hospital Alvarez-Buylla, Mieres, Asturias
2. Department of Pathology, Hospital de Jove, Gijón, Asturias
3. Deparment of Ophthalmology, Hospital San Agustín, Avilés, Asturias
4. Deparment of Pathology, Hospital Central de Asturias, Oviedo, Asturias
5. Deparment of Surgery, Hospital de Jove, Gijón, Asturias - Spain