The application of optical coherence tomography angiography in Alzheimer's disease: A systematic review

INTRODUCTION: Discovering non‐invasive and easily acquired biomarkers that are conducive to the accurate diagnosis of dementia is an urgent area of ongoing clinical research. One promising approach is retinal imaging, as there is homology between retinal and cerebral vasculature. Recently, optical coherence tomography angiography (OCT‐A) has emerged as a promising new technology for imaging the microvasculature of the retina. METHODS: A systematic review and meta‐analysis was conducted to examine the application of OCT‐A in dementia. RESULTS: Fourteen studies assessing OCT‐A in preclinical Alzheimer's disease (AD), mild cognitive impairment, or AD were included. Exploratory meta‐analyses revealed a significant increase in the foveal avascular zone area and a significant decrease in superficial parafoveal and whole vessel density in AD, although there was significant heterogeneity between studies. DISCUSSION: Although certain OCT‐A metrics may have the potential to serve as biomarkers for AD, the field requires further standardization to allow conclusions to be reached regarding their clinical utility.