Effect of obstructive sleep apnea syndrome on corneal thickness

Obstructive sleep apnea syndrome (OSAS) might be a risk factor for the development of eye disorders. The aim of the study was to evaluate the effect of OSAS on central corneal thickness (CCT). A total of 195 patients were enrolled in the study, and underwent polysomnography. Patients were divided according to their apnea-hypopnea index (AHI) scores into control group (AHI < 5), mild (AHI, 5-15), moderate (AHI, 15-30), and severe OSAS (AHI > 30) groups. In ophthalmological examinations, CCT, auto refractometer measurement, tear break-up time, and Schrimer's test results were evaluated. Central corneal thickness was significantly decreased in patients with OSAS compared to the control group (542.14 ± 31.21 vs. 569.92 ± 13.46, p < 0.001). As the severity of OSAS increased, CCT decreased (mild OSAS = 567.48 ± 23 mm, moderate OSAS = 530.21 ± 30.2 mm, and severe OSAS = 557.97 ± 16.52 mm, respectively, p < 0.001). The mean values of auto refractometer, tear break-up time, and Schrimer's test were similar between the groups (p > 0.05). CCT was negatively correlated with AHI, oxygen desaturation index, desaturation percentages, and positively correlated with minimum oxygen saturation values (p < 0.05). This study showed that central corneal thickness is inversely correlated with the severity of OSAS. OSAS affects all organ systems particularly cardiovascular and neurological mechanisms. Further studies are warranted to evaluate the effect of OSAS treatment on CCT.