Abstract
Purpose:
Few studies have documented that nocturnal continuous positive airway pressure (CPAP) therapy was associated with an increase in intraocular pressure (IOP) in patients with obstructive sleep apnea syndrome (OSAS). We re-examined the effect of CPAP therapy on the IOP of OSAS patients.
Methods:
The IOP of two different groups of newly diagnosed OSAS patients was compared at their first sleep lab exam without CPAP treatment (non-CPAP treated group; n=20) and at their second sleep lab exam with CPAP treatment (CPAP treated group; n=31). The sleep lab exam (sleep period: from 11:00 pm until 6:00 am) included IOP measurements, a complete ophthalmologic exam and nocturnal hemodynamic recordings. The IOP was measured serially using rebound tonometer (IOP; ICARE® PRO) performed while in sitting and supine positions before, during and after the sleep period. We compared the difference in IOP of non-CPAP and CPAP groups.
Results:
The mean IOP of the non-CPAP and CPAP groups measured in sitting position before the sleep period was 14.14±2.41 mmHg and 13.62±2.07 mmHg, respectively (p=0.48). Assuming a supine position for 1 minute, significantly increased the IOP by 2.18±2.46 mmHg and 1.91±2.16 mmHg for both the non-CPAP and CPAP groups (Paired t-test; p=0.027, p=0.034, respectively), but this IOP rise showed no difference between the two groups. The IOP significantly increased further after 7 hours of sleep in the supine position, and the mean IOP of the non-CPAP and CPAP groups was 19.41±4.11 mmHg and 19.69±5.61 mmHg, respectively (independent t-test p=0.76). The rise in IOP for both groups was not correlated with any hemodynamic parameters.
Conclusions:
OSAS patients have a significant rise in IOP during the sleep period when comparing measurements before and after the sleep period; however, CPAP therapy did not affect the measurements of IOP. In our study, the rise in nocturnal IOP in OSAS patients is not related to changes in hemodynamic parameters.