TY - JOUR T1 - Corneal confocal microscopy identifies corneal nerve fibre loss and increased dendritic cells in patients with long COVID JF - British Journal of Ophthalmology JO - Br J Ophthalmol DO - 10.1136/bjophthalmol-2021-319450 SP - bjophthalmol-2021-319450 AU - Gulfidan Bitirgen AU - Celalettin Korkmaz AU - Adil Zamani AU - Ahmet Ozkagnici AU - Nazmi Zengin AU - Georgios Ponirakis AU - Rayaz A Malik Y1 - 2021/07/08 UR - http://bjo.bmj.com/content/early/2021/07/08/bjophthalmol-2021-319450.abstract N2 - Background/Aims Long COVID is characterised by a range of potentially debilitating symptoms which develop in at least 10% of people who have recovered from acute SARS-CoV-2 infection. This study has quantified corneal sub-basal nerve plexus morphology and dendritic cell (DC) density in patients with and without long COVID.Methods Forty subjects who had recovered from COVID-19 and 30 control participants were included in this cross-sectional comparative study undertaken at a university hospital. All patients underwent assessment with the National Institute for Health and Care Excellence (NICE) long COVID, Douleur Neuropathique 4 (DN4) and Fibromyalgia questionnaires, and corneal confocal microscopy (CCM) to quantify corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD), corneal nerve fibre length (CNFL), and total, mature and immature DC density.Results The mean time after the diagnosis of COVID-19 was 3.7±1.5 months. Patients with neurological symptoms 4 weeks after acute COVID-19 had a lower CNFD (p=0.032), CNBD (p=0.020), and CNFL (p=0.012), and increased DC density (p=0.046) compared with controls, while patients without neurological symptoms had comparable corneal nerve parameters, but increased DC density (p=0.003). There were significant correlations between the total score on the NICE long COVID questionnaire at 4 and 12 weeks with CNFD (ρ=−0.436; p=0.005, ρ=−0.387; p=0.038, respectively) and CNFL (ρ=−0.404; p=0.010, ρ=−0.412; p=0.026, respectively).Conclusion Corneal confocal microscopy identifies corneal small nerve fibre loss and increased DCs in patients with long COVID, especially those with neurological symptoms. CCM could be used to objectively identify patients with long COVID.The data that support the findings of this study are available from the corresponding author (ORCID: 0000-0002-0509-5649) upon reasonable request. ER -