Neuroinflammatory findings with corneal COnfocal microscopy in long COVID‐19 patients, 2years after acute SARS‐CoV‐2 infection

Purpose: To describe corneal confocal microscopy findings in patients with long COVID‐19 with persistent symptoms over 20 months after SARS‐CoV‐2 infection.Methods: Cross‐sectional comparative transversal study that included a total of 53 patients, 33 patients with Long COVID‐19 and 22 controls matched in age and gender. Long COVID‐19 diagnosis was established according to the World Health Organization criteria Corneal confocal microscopy Heidelberg Retina Tomograph II (Heidelberg Engineering, Heidelberg, Germany) was performed to evaluate sub‐basal nerve plexus morphology (corneal nerve fibre density, nerve fibre length, nerve branch density, nerve fibre total branch density, nerve fibre area, and nerve fibre width). Dendritic cells density and area, along with microneuromas and other morphological changes of the nerve fibres were recorded.Results: Long COVID‐19 patients presented reduced corneal nerve density and branch density as well as shorter corneal nerves compared to the control group. Additionally, Long COVID‐19 patients showed an increased density of Dendritics Cells with also greater area than that found in the control group of patients without systemic diseases. Microneuromas were detected in 24.2% of Long COVID‐19 patients.Conclusions: Long COVID‐19 patients exhibited altered corneal nerve parameters and increased DC density over 20 months after acute SARS‐CoV‐2 infection. These findings are consistent with a neuroinflammatory condition hypothesized to be present in patients with long COVID‐19, highlighting the potential role of corneal confocal microscopy as a promising noninvasive technique for the study of patients with long COVID‐19.