METHODS: This is a cross-sectional study involving 27 patients with symptoms of OSAS seen at a tertiary institutional center and 25 normal controls performed between June 2015 and June 2016. All patients and controls underwent a polysomnography (PSG) test and were diagnosed with OSAS based on the apnea-hypopnea index (AHI). Patients are those with OSAS symptoms and had AHI > 5, whereas controls are staffs from the ophthalmology clinic without clinical criteria for OSAS and had PSG result of AHI