1. Department of Medicine, University of Bern, Inselspital CH-3000 Bern
2. Department of Otorhinolaryngology, University of Bern, Inselspital CH-3000 Bern
3. Department of Ophthalmology, University of Bern, Inselspital CH-3000 Bern
4. Policlinique universitaire de médecine Geneva