The effect of positive airway pressure therapy on intraocular pressure and retina in severe obstructive apnea syndrome.

To identify and compare changes in intraocular pressure (IOP), macular, and peripapillary retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) measurements before and after 3 months of positive airway pressure (PAP) therapy in patients with severe obstructive sleep apnea syndrome (OSAS). Twenty-five patients diagnosed with severe OSAS in the neurology sleep outpatient clinic were included in the study. Ophthalmologic examinations were performed at the time of diagnosis and after 3 months of PAP therapy. Statistical analysis of comparisons of pre-treatment and post-treatment measurements of IOP and OCT was performed. Before the PAP therapy, the correlations between central corneal thickness (CCT), body mass index (BMI), OCT, IOP, and sleep parameters were statistically analyzed. Compared to the pre-treatment measurements at the time of diagnosis, post-treatment measurements showed insignificant decrease in IOP, significant increase in mean macular thickness and significant thinning in superior nasal RNFL. There was no correlation found between pre-treatment measurements including IOP, OCT, CCT, BMI, and sleep parameters. The effect of intermittent hypoxia and hypercapnia on the IOP and macula may be reversible in severe OSAS patients receiving 3 months of PAP therapy, but the reversibility of the neurodegenerative effects of OSAS on RNFL with this treatment seems controversial. OCT can be considered to be a promising technique for monitoring disease progression under PAP therapy in patients with severe OSAS.