Retinal reflectance spectra measured using hyperspectral imaging are associated with prevalent dementia in a general older Japanese population

Advances in retinal hyperspectral imaging demonstrate its potential usefulness in neurodegenerative disorders; however, community-based evidence is lacking. We examined associations between retinal reflectance spectra and prevalent dementia in 857 Hisayama Study residents aged ≥ 65 years who underwent eye and dementia examinations in 2022–2023. Retinal relative reflectance spectra were measured in four retinal regions using hyperspectral imaging; ganglion cell-inner plexiform layer (GC-IPL) thickness was assessed using optical coherence tomography (OCT). Principal component analysis (PCA) was performed on Z-standardized reflectance values for each retinal region and all four regions combined. PCA-derived scores were constructed as the linear predictor from logistic regression models including the first four principal components, with higher scores indicating lower overall reflectance. Higher PCA-derived scores were significantly associated with higher odds of prevalent dementia in all regions, strongest in inferotemporal region (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.46–3.35) and combined regions (OR, 2.20; 95% CI, 1.42–3.40). After internal validation, the shrinkage-adjusted ORs were 2.31 and 2.52, and C-statistics were 0.707 and 0.688, respectively. Coexisting high PCA-derived scores and GC-IPL thinning further had higher odds of prevalent dementia in combined regions (OR, 3.87) and inferotemporal region (OR, 6.98). Thus, hyperspectral imaging, particularly when considered alongside OCT, may capture retinal alterations associated with dementia in older adults.