Correlation between retinal nerve fibre layer thickness and white matter lesions in Alzheimer's disease

Objectives Early diagnosis in Alzheimer's disease (AD) is crucial in order to implement new therapeutic strategies. The retina is embryologically related to the brain. Thus, the possible usefulness of optical coherence tomography (OCT) in the early detection of AD is currently being studied. Our aim was to study the relationship between retinal nerve fiber layer (RNFL) thickness and AD. Methods We undertook an observational, analytical, cross‐sectional study with consecutive sampling of 32 patients with AD or mild cognitive impairment and a group of healthy controls (C). The total number of eyes studied was 64. An ophthalmological and a comprehensive neuropsychological evaluation were performed in all participants. Quantification of white matter lesions and study of atrophy of the hippocampus by cerebral magnetic resonance were also performed. Results We observed a significant linear trend towards a thinning of RNFL as the degree of cognitive deterioration increased, in the superior and temporal quadrants of the retina. A significant correlation was also noted between the mean thickness of the RNFL of the left temporal quadrant and occipital white matter lesions (r = −0.579, p = 0.038). Conclusions OCT could be a safe, rapid noninvasive tool providing useful biomarkers in the early detection of cognitive deterioration and AD. Key Points Optical coherence tomography (OCT) is a noninvasive imaging technology that provides high‐resolution cross‐sectional images of the retinal nerve fiber layer (RNFL) and measures macular thickness and volume A significant linear trend towards a thinning of RNFL as the degree of cognitive deterioration increased in the superior and temporal quadrants of the retina was found RNFL of the left temporal quadrant was associated with occipital white matter lesions Findings emphasize the usefulness of the OCT in the early diagnosis of mild cognitive impairment and Alzheimer's disease