Subclinical neurovascular and immune correlates of post-COVID-19 syndrome detected by retinal imaging.

BACKGROUND

Post-COVID-19 Syndrome (PCS) encompasses a range of persistent symptoms, including cognitive and autonomic disturbances, potentially linked to microvascular or neuroinflammatory mechanisms. Retinal imaging provides a non-invasive window into the central nervous system and vascular integrity. This study aimed to assess retinal structural and microvascular alterations in PCS patients and explore their relationship with symptom severity.

METHODS

In this monocentric, cross-sectional, exploratory study, we performed Optical Coherence Tomography (OCT) and OCT Angiography (OCTA) in patients with PCS and a group of COVID-19 recovered individuals. Multiple circulating biomarkers reflecting endothelial dysfunction and chronic inflammation were measured. Associations with validated symptom scores (PCS Score, C19-YRS, PHQ-9, GAD-7) were evaluated.

RESULTS

After adjusting for age and gender, no significant differences were observed in OCTA-derived vessel density (VD) or foveolar avascular zone (FAZ) between PCS patients and COVID-19-recovered controls. However, PCS patients exhibited significant thinning of the peripapillary retinal nerve fibre layer (pRNFL), ganglion cell inner plexiform layer (GCIP), and total macular volume (TMV). Lower values of these structural parameters were consistently observed in patients with higher symptom severity. Vascular parameters (VD and FAZ) were not related to clinical scores. Higher MCP-1 levels, a chemokine associated with chronic inflammation, were linked to lower inner nuclear layer and GCIP thickness.

CONCLUSION

Structural retinal alterations in PCS were associated with symptom burden and may reflect underlying neuroinflammatory or neurodegenerative processes. OCT parameters could serve as potential non-invasive biomarkers, warranting further investigation in longitudinal, multicenter studies.