Effect of prolonged supine position on the intraocular pressure in patients with obstructive sleep apnea syndrome.

PURPOSE: Obstructive sleep apnea syndrome (OSAS) patients are at risk of glaucoma but the risk increases if they have higher intraocular pressure (IOP) while sleeping. We aim to evaluate the postural effect of upright and prolong supine positions on IOP in these patients.

METHODS: This is a cross-sectional study involving 27 patients with symptoms of OSAS seen at a tertiary institutional center and 25 normal controls performed between June 2015 and June 2016. All patients and controls underwent a polysomnography (PSG) test and were diagnosed with OSAS based on the apnea-hypopnea index (AHI). Patients are those with OSAS symptoms and had AHI > 5, whereas controls are staffs from the ophthalmology clinic without clinical criteria for OSAS and had PSG result of AHI < 5. IOP was measured 10 min after sitting, immediately and at 30 min on supine position and immediately after resuming sitting position. The main outcome measures were the changes in mean IOP in different positions.

RESULTS: The increase in mean IOP when changing from sitting to supine position was significantly higher in OSAS patients in both the right eye (RE) (1.01 ± 1.14 vs 0.44 ± 0.41 mmHg, p = 0.033) and left eye (LE) (1.20 ± 1.26 vs 0.48 ± 0.62 mmHg, p = 0.044). After 30 min supine, the IOP in OSAS patients showed a further increase in IOP than controls (RE 1.20 ± 1.79 vs 0.12 ± 0.66 mmHg, p = 0.001 and LE 0.59 ± 2.00 vs 0.15 ± 0.78 mmHg, p = 0.246). Higher IOP when sitting post supine is associated with higher IOP on supine position.

CONCLUSION: IOP increase is significantly more in OSAS patients on prolong supine position.