text: Corneal confocal microscopy identifies corneal nerve fibre loss and increased dendritic cells in patients with long COVID 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 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 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 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 