1. Department of Ophthalmology, 251 General Air Force Hospital, Hellenic Air Force, Athens, Greece.
2. 120 Flight Training Wing Medical Service, Hellenic Air Force, Kalamata, Greece.
3. Department of Otorhinolaryngology, 251 General Air Force Hospital, Hellenic Air Force, Athens, Greece.
4. Department of Neurology, University Hospital of Thessaly, Larisa, Greece.
5. Department of Otorhinolaryngology, University Hospital of Thessaly, Larisa, Greece.