Retinal nerve fiber thickness is reduced in sleep apnea syndrome

Abstract

To investigate the prevalence of glaucoma, visual field abnormalities, as well as changes in retinal nerve fiber layer in patients with obstructive sleep apnea syndrome (OSAS). In this cross-sectional study, 51 patients with OSAS were included. Based on apnea hypopnea index (AHI), there were 26, 6 and 19 cases of severe (AHI⩾30), moderate (15⩽AHI<30), and mild (5⩽AHI<15) OSAS, respectively. The control group was matched for age, sex and body mass index. Prevalence of glaucoma and ocular hypertension as well as the following values were assessed and compared between two groups: best-corrected visual acuity, intraocular pressure, central corneal thickness (CCT), cup:disk ratio, mean deviation (MD), pattern standard deviation, and retinal nerve fiber layer (RNFL) parameters using glaucoma diagnosis measurement (GDx). Seven eyes (6.7%) had intraocular pressure (IOP)>21mmHg; of these, four eyes (3.9%) had glaucoma. No significant difference was detected in CCT between the two groups. IOP was significantly higher in the OSAS group before (p<0.001) and after (p<0.001) correcting for CCT. There was a significant difference between groups in MD and most GDx parameters including DISK (temporal-superior-nasal-inferior-temporal) average (p=0.002), superior average (p=0.05) and nerve fiber indicator (NFI) (p=0.03), where those in the patient group showed lower values. There was a significant positive correlation between AHI and both IOP and NFI. OSAS patients had a higher prevalence of glaucoma and ocular hypertension. OSAS patients also had higher IOP, worse visual field indices, and lower RNFL parameters compared with the control group.