Relationship between Retinal Nerve Fiber Layer Thickness and Cognitive Measures in Mild Cognitive Impairment Patients.

Exploratory biomarkers of Alzheimer's disease (AD) are often expensive and invasive, which limits their clinical application.1 One potential biomarker is visual-system assessment in the early stages of AD. The retina is an extension of the central nervous system and can be accessed easily via imaging techniques, such as optical-coherence tomography (OCT).2,3 Many in vivo studies have investigated the accumulation of Aβ plaques and structural abnormalities in the retina of patients with AD.2,3 Patients with mild cognitive impairment (MCI) have thinner retinal-nerve-fiber layers (RNFLs) than control subjects. A number of studies also investigated the association between RNFL thickness and cognitive function, but the results were inconsistent.2,3 In this study, we retrospectively examined the cognitive function of patients with MCI using domain-specific neuropsychological tests, and investigated the association between RNFL thickness and cognitive function in several subdomains.