Mutlu Acar1, Hikmet Fırat2, Canan Gürdal3. 1. Department of Ophthalmology, Ministry of Health, Ankara Diskapi Yildirim Beyazit Training and Research Hospital, 06110, Ankara, Turkey. m_acar@hotmail.com. 2. Department of Chest Diseases and Sleep Center, Ministry of Health, Ankara Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey. 3. Department of Ophthalmology, Ministry of Health, Ankara Diskapi Yildirim Beyazit Training and Research Hospital, 06110, Ankara, Turkey.