Continuous 24-Hour Intraocular Pressure-Related Changes in Patients with Obstructive Sleep Apnea with and without Normotensive Glaucoma

Importance: Obstructive apneas during sleep can affect the intraocular pressure fluctuation over 24 hours. Background: Several studies found an increased prevalence of normal-tension glaucoma (NTG) in patients with obstructive sleep apneas (OSA). Design: Prospective exploratory study conducted in academic setting. Participants: Three patients diagnosed with OSA and 3 with OSA and NTG. Methods: Ambulatory blood pressure monitoring (ABPM), overnight respiratory polygraphy and IOP-related changes monitoring in an eye by a contact lens sensor (CLS) over a 24-hour period. Main outcome measure: We analyzed the effect of apneas on the CLS reading. Wake to sleep slope (W/S) and sleep to wake slope (S/W) were tested. Results: An 11% increase in the mean (95% CI) overnight CLS outputs, from 185.2 (125.4-273.8) mVeq to 205.1 (192.4-219.3) mVeq, was associated with the occurrence of apneas lasted 120 s (p=0.001). We found no correlation between ABPM and IOP or ABPM and apneas' duration. The W/S slopes were similar between the two groups (P=0.41), while the S/W slopes in the NTG patients differ considerably from patients without NTG (P=0.03), with a far less steep slope in the first group. Conclusions and Relevance: Obstructive apneas during sleep could affect IOP-related changes in a cumulative way. The smoother W/S and S/W slopes in NTG reveal a sort of inertia that could make some eyes more susceptible to damage following exposure to apneas.