Quantitative comparison of mean macular thickness in COVID-19 patients versus healthy individuals using optical coherence tomography

SARS-CoV-2 is associated with systemic inflammation, vascular dysfunction, and potential ocular involvement. While structural retinal changes have been observed in some patients, the long-term impact of COVID-19 on macular architecture remains unclear, §particularly in unvaccinated populations. To evaluate differences in central macular thickness (CMT) between post-COVID-19 patients and healthy individuals using optical coherence tomography (OCT), with age-stratified analysis. A prospective case-control study conducted at a specialized ophthalmology center in Brazil during the early vaccination phase. A total of 76 unvaccinated participants were included: 29 patients with prior COVID-19 (58 eyes) and 47 healthy controls (94 eyes). OCT was performed at least 14 days after PCR-confirmed infection. The overall mean CMT was 246.93 ± 23.30 μm. No significant difference was found between the COVID-19 and control groups (242.54 ± 19.76 μm vs. 249.63 ± 25.06 μm; p = 0.10). However, among participants aged ≥ 42 years, post-COVID-19 patients had significantly lower CMT compared to age-matched controls (241.00 ± 21.90 μm vs. 256.85 ± 28.58 μm; p = 0.04). No significant difference was observed in the < 42 years group. OCT angiography revealed no qualitative vascular abnormalities in either group. Our findings suggest that SARS-CoV-2 infection may be associated with subtle retinal thinning in older adults, even in the absence of acute symptoms or visual complaints. These results highlight the importance of age-stratified analysis and support further investigation into the long-term ocular effects of COVID-19.