Selective vulnerability of the macular ganglion cell layer to nocturnal hypoxia in obstructive sleep apnea: A 3-year longitudinal study.

OBJECTIVE

To evaluate the association between nocturnal hypoxemia metrics in obstructive sleep apnea (OSA) and subclinical structural alterations of retinal neurons.

METHODS

In this prospective study, 79 newly diagnosed OSA patients underwent overnight polysomnography and spectral-domain optical coherence tomography. OSA-related nocturnal hypoxemia was assessed using the oxygen desaturation index (ODI). Associations between ODI and retinal parameters were assessed using linear mixed-effects models, and longitudinal structural changes were evaluated in 25 participants after 3 years.

RESULTS

Higher ODI was associated with reduced minimum ganglion cell layer (GCL) thickness (P = 0.011), whereas mean GCL showed a borderline association (P = 0.052). Peripapillary retinal nerve fiber layer (RNFL) thickness was not significantly associated with ODI (P = 0.466). GCL thinning demonstrated a focal distribution, most prominent in the superotemporal sector. Longitudinal analysis indicated a nonlinear trajectory of GCL loss, with accelerated decline in moderate OSA (P = 0.007) and relative stabilization in severe OSA. Each one-event-per-hour increase in ODI was associated with a 0.10 μm reduction in minimum GCL thickness (β = -0.10, 95% CI -0.17 to -0.02, P = 0.011).

CONCLUSIONS

Among OSA-related nocturnal hypoxemia metrics, ODI showed the strongest associated with selective early GCL thinning, while RNFL changes are not detectable at this stage. These findings suggest that GCL could serve as a structural marker of subclinical neurodegeneration in OSA.