Microvascular changes in the macular area in patients with obstructive sleep apnoea syndrome compared to controls: A systematic review and meta-analysis.

To investigate retinal microvascular changes in patients with obstructive sleep apnoea syndrome (OSAS) compared to healthy controls. PUBMED and Scopus were searched for published studies comparing retinal microvascular indices on optical coherence tomography angiography (OCTA), between patients with OSAS and controls. Mean Differences (MD) with 95% confidence interval (CI) were computed for the comparisons. Revman 5.3 was used for the analysis. Our study was registered with PROSPERO with registration ID: CRD42024523329. 8 studies were included in our analysis. Foveal avascular zone (FAZ) area was enlarged in patients with OSAS compared to controls (MD = 0.04; 95% CI: 0.02, 0.07, p = 0.0004, I2 = 71%). The superficial capillary plexus vessel density was found to be decreased in patients with OSAS compared to controls in the foveal (MD = -1.54; 95% CI: -2.49, -0.58, P = 0.002, I2 = 0%), parafoveal (MD = -1.01; 95% CI: -1.48, -0.54, p < 0.0001, I2 = 0%) and whole image (MD = -1.40; 95% CI: -2.04, -0.76, p < 0.0001, I2 = 85%). The deep capillary plexus vessel density was found to be decreased in the foveal (MD = -2.32; 95% CI: -3.57, -1.06, p = 0.0003, I2 = 0%) parafoveal (MD = -2.05; 95% CI: -3.71, -0.39, p = 0.02, I2 = 91%) and whole image (MD = -1.37; 95% CI: -2.58, -0.16, p = 0.03, I2 = 88%). Subgroup analysis confirmed this finding in patients with mild, moderate and severe OSAS. Patients with OSAS exhibit an enlarged FAZ area and decreased vessel density in both the superficial and deep capillary plexus compared to control patients. These findings suggest that chronic intermittent hypoxia in patients with OSAS might adversely affect the retinal microvasculature. Prompt measures to prevent or treat OSAS are recommended.