Abstract
Purpose: Visual impairment is a major cause of disability and impairment of cognitive function in older people. Brain structuralchanges associated with visual function impairment are not well understood. The objective of this study was to assess the associationbetween visual function and cortical thickness in older adults.Methods: Participants were selected from the French population-based ESPRIT cohort of 2259 community-dwelling adults ≥65years old enrolled between 1999 and 2001. We considered visual function and brain MRI images at the 12-year follow-up inparticipants who were right-handed and free of dementia and/or stroke, randomly selected from the whole cohort. High-resolutionstructural T1-weighted brain scans acquired with a 3-Tesla scanner. Regional reconstruction and segmentation involved using theFreeSurfer image-analysis suite.Results: A total of 215 participants were included (mean [SD] age 81.8 [3.7] years; 53.0% women): 30 (14.0%) had central visionloss and 185 (86.0%) normal central vision. Vision loss was associated with thinner cortical thickness in the right insula (within thelateral sulcus of the brain) as compared with the control group (mean thickness 2.38 [0.04] vs 2.50 [0.03] mm, 4.8% thinning, pcorrected= 0.04) after adjustment for age, sex, lifetime depression and cardiovascular disease.Conclusion: The present study describes a significant thinning of the right insular cortex in older adults with vision loss. The insulasubserves a wide variety of functions in humans ranging from sensory and affective processing to high-level cognitive processing.Reduced insula thickness associated with vision loss may increase cognitive burden in the ageing brain.