Impact of prolonged obstructive sleep apnea syndrome disease course on retinal-choroidal microcirculation: a WF-SS-OCTA study.

PURPOSE: This study used wide-field swept-source optical coherence tomography angiography (WF-SS-OCTA) to evaluate changes in macular vascular density in patients with obstructive sleep apnea syndrome (OSAS) at different stages of disease duration, aiming to elucidate the effects of prolonged disease course on retinal and choroidal microcirculation.

METHOD: This cross-sectional study included 54 patients with obstructive sleep apnea syndrome (OSAS) who were newly diagnosed by polysomnography (PSG). Patients were divided according to disease duration into a < 10-year group (Group 1: 29 patients, 29 eyes) and a > 10-year group (Group 2: 25 patients, 25 eyes). Wide-field swept-source optical coherence tomography angiography (WF-SS-OCTA) was used to obtain data from concentric rings with diameters of 3, 6, 9, and 12 mm centered on the macula. Fundus structural and vascular density parameters were compared between the two groups, and the relationships between PSG parameters and microcirculatory parameters were analyzed. Partial correlation and multiple linear regression analyses were further performed to identify independent associated factors.

RESULTS

Compared with Group 1, retinal nerve fiber layer (RNFL) thickness was reduced in Group 2, with significantly lower thickness in the second concentric ring (P < 0.05). In contrast, choroidal thickness was increased in Group 2, with significant differences observed in the inner rings (rings 1-2, P < 0.05). Vessel densities in the superficial vascular complex (SVC) and deep vascular complex (DVC) showed a decreasing trend but did not differ significantly between the two groups. Conversely, choroidal vessel volume (CVV) was significantly increased in Group 2, with significant differences observed in the inner rings (rings 1-3, P < 0.05). Correlation analysis showed that both choroidal thickness and the inner ring (ring 1) of CVV were positively correlated with the percentage of total monitoring time during which oxygen saturation (SpO2) was <90% throughout the entire night's sleep (T90%). This association remained significant after adjustment for age, sex, and body mass index in partial correlation analyses. Multiple linear regression analysis further confirmed that T90% was an independent predictor of choroidal thickness (β = 0.363, P = 0.008) and CVV (β = 0.356, P = 0.011).

CONCLUSION

A longer disease duration of OSAS was associated with RNFL thinning, increased choroidal thickness, and increased CVV in the central macular region, suggesting progressive retinal neurodegeneration and compensatory choroidal remodeling. The extent of cumulative hypoxic exposure (T90%) was independently associated with changes in choroidal structure and blood flow. These findings provide new insights into retinal and choroidal microvascular alterations in patients with OSAS and highlight the importance of monitoring macular retinal and choroidal health, particularly vascular changes in the macular region, in patients with a prolonged disease course.