Neuroretinal Alterations in Persistent COVID-19: A Two-Year OCT Follow-Up

Background/Objectives: To evaluate long-term neuroretinal changes in patients with persistent COVID-19 (PC) versus asymptomatic controls, using optical coherence tomography (OCT) over a two-year follow-up. Methods: This prospective longitudinal study enrolled 133 participants: 94 PC patients and 39 control subjects. Participants underwent comprehensive ophthalmological assessment at baseline, at 1 year (voluntary), and at 2 years. Structural retinal changes were analysed using spectral-domain OCT with the Bruch's Membrane Opening-Minimum Rim Width and Posterior Pole protocols. Longitudinal analyses focused on within-subject change from baseline to 2 years and on between-group comparisons of these change scores, with Bonferroni correction applied within predefined families of comparisons. Results: The most robust corrected between-group longitudinal finding was a greater decrease in the central macular sector (C0) of the inner plexiform layer (IPL) in PC patients than in control subjects. Conclusions: Although these findings suggest possible subtle inner retinal involvement in PC patients, particularly in the central IPL, the results should be interpreted cautiously because of the modest control sample, control-group heterogeneity, and the exploratory nature of the sectoral OCT analyses. OCT may be useful in research settings as a complementary tool for exploring subtle neuroretinal changes in PC patients; however, its clinical utility and role as a validated biomarker remain unproven.