Alzheimer’s disease (AD) is a leading cause of dementia worldwide, but its clinical diagnosis continues to pose a challenge to neurologists and general practitioners. A growing body of research suggests that eye doctors may be able to play a role too, as both conventional OCT and OCT angiography (OCT-A) have the potential to detect retinal structural and microvascular changes in patients with AD that may serve as biomarkers for the disease, a recent literature review suggests.

A team narrowed down their PubMed database search to 71 studies of 6,757 patients (2,350 AD, 793 mild cognitive impairment, 2,902 healthy controls and 841 other neurodegenerative diagnoses). Mean baseline age ranged from 70 to 73 in those with cognitive challenges and healthy controls.

The majority of studies noted significant structural and functional decline in AD patients when compared with controls. Although analysis of mild cognitive impairment patients yielded more mixed results, the researchers often noted a similar pattern of decline among those patients relative to controls. Also, OCT and OCT-A measurements correlated with established measures of AD, such as neuropsychological testing and neuroimaging.

“OCT and OCT-A show great potential as noninvasive technologies for the diagnosis of AD,” the researchers wrote in their paper. “However, further research is needed to determine whether there are AD-specific patterns of structural or microvascular change in the retina and optic nerve that distinguish AD from other neurodegenerative diseases.” They concluded that the development of sensitive and specific OCT and OCT-A parameters is necessary before they can be used to detect AD in clinical settings.

Song A, Johnson N, Ayala A, et al. Optical coherence tomography in patients with Alzheimer’s disease: what can it tell us? Eye Brain. 2021;13:1-20.