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Background: Visual rating of medial temporal lobe atrophy (MTA) is an accepted biomarker of Alzheimer’s disease. Corneal confocal microscopy (CCM) is a non-invasive ophthalmic imaging biomarker of neurodegeneration. We sought to determine the diagnostic accuracy of CCM to distinguish mild cognitive impairment (MCI) and dementia from no cognitive impairment (NCI) in relation to MTA rating.Methods: Subjects aged 60-85 with NCI, MCI and dementia were recruited from the geriatric and memory clinic in Rumailah Hospital, Doha, Qatar between 18/09/16 and 31/07/19. The diagnosis of MCI and dementia were based on the International Classification of Diseases (ICD-10) criteria. Subjects underwent cognitive screening using the Montreal Cognitive Assessment (MoCA), CCM and MTA rating on MRI. Statistical tests used were ANOVA with Bonferroni’s post hoc test, kappa statistics and receiver operating characteristic (ROC) curve analysis. A two-tailed P value of ≤0.05 was considered significant.Results: 182 subjects with NCI (n=36), MCI (n=80) and dementia (n=66), including AD (n=19, 28.8%), VaD (n=13, 19.7%) and combined AD (n=34, 51.5%) were studied. CCM showed a progressive reduction in corneal nerve fiber density (CNFD, fibers/mm2) (32.0±7.5 vs 24.5±9.6 vs 20.8±9.3, p2) (90.9±46.5 vs 59.3±35.7 vs 53.9±38.7, p2) (22.9±6.1 vs 17.2±6.5 vs 15.8±7.4, pConclusions: The diagnostic accuracy of CCM, a non-invasive ophthalmic biomarker of neurodegeneration was high and comparable with MTA rating for dementia and superior to MTA rating for MCI.