Key Points Question Is the peripapillary retinal nerve fiber layer (RNFL) thickness correlated with brain alterations in regions that are vulnerable to neurodegenerative processes? Findings Among 104 elderly people with dementia in this population-based study, a thicker RNFL was associated with a higher hippocampal fraction and better diffusion tensor imaging variables in the global and hippocampal part of the cingulum, 2 regions closely associated with the neurodegenerative processes of Alzheimer disease. Meaning The assessment of axonal thickness in the retina, which is a quick measurement to perform, may provide some elements of brain magnetic resonance imaging abnormalities at an early stage of neurodegeneration.

Retinal nerve fiber layer (RNFL) thickness is reduced in Alzheimer’s patients. However, whether it is associated with early evolution of cognitive function is unknown. Within 427 participants from the Three-City-Alienor longitudinal population-based cohort, we explored the relationship between peripapillary RNFL thicknesses and the evolution of cognitive performance. RNFL was assessed at baseline by spectral domain optical coherence tomography; cognitive performances were assessed at baseline and at 2 years, with the Mini–Mental State Examination, the Isaacs’ set test, and the Free and Cued Selective Reminding Test (FCSRT). Multivariate linear mixed models were performed. The RNFL was not associated with initial cognitive performance. Nevertheless, a thicker RNFL was significantly associated with a better cognitive evolution over time in the free delayed recall (p = 0.0037) and free + cued delayed recall (p = 0.0043) scores of the FCSRT, particularly in the temporal, superotemporal, and inferotemporal segments. No associations were found with other cognitive tests. The RNFL was associated with changes in scores that assess episodic memory. RNFL thickness could reflect a higher risk of developing cognitive impairment over time.

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