Could Nocturnal Chronic Hypoxia Cause Ocular Surface Symptoms by Affecting Limbal Epithelial Cells in Patients With Obstructive Sleep Apnea?

Purpose: To investigate the effect of nocturnal chronic hypoxia on the thickness changes of the corneal limbal epithelial area that provides regeneration of the corneal epithelium and ocular surface evaluation parameters in patients with obstructive sleep apnea (OSA).

Methods: All patients diagnosed with OSA and the control group underwent a complete ophthalmological examination, including slit-lamp examination and funduscopy. Tear break-up time, Schirmer test-I, Ocular Surface Disease Index Questionnaire, and anterior segment optical coherence tomography were performed with fluorescein sterile strip for ocular surface evaluation.

Results: Oxygenation levels of patients during night sleep were different between mild-severe and moderate-severe groups. The Ocular Surface Disease Index results were statistically significantly different between the severe OSA group and the mild OSA group, and between the control group and all other OSA groups (P < 0.05). The limbal epithelial thickness (LET) value was found to be lower in the moderate OSA group than in the mild OSA group and the control group and was statistically significantly higher than in the severe OSA group. In the severe OSA group, the LET value was found to be statistically significantly lower than all other groups (P < 0.05).

Conclusions: In the literature, there is no study evaluating the effect of prolonged hypoxia on limbus epithelium as in patients with OSA. In this study, LET was measured to be statistically significantly thinner as the severity of OSA increased. Considering these results, it can be concluded that the proliferation of limbal stem cells is reduced in prolonged hypoxia.