Detecting Alzheimer's Disease Using Ocular Tissue and Imaging: What Do We Know?

Alzheimer's disease (AD) is a progressive neurodegenerative condition with increasing global prevalence. As early diagnosis becomes critical for timely symptomatic management, noninvasive and easily accessible biomarkers are needed. Given the shared embryologic origins between the eye and the brain, ocular imaging has emerged as a promising diagnostic technique. This review summarizes the associations between AD, ocular imaging and fluid biomarkers in the anterior and posterior segment. We also describe the underlying pathophysiology that explains the connections between each ocular structure and the brain in the context of AD. Optical coherence tomography (OCT), OCT angiography, and fundus photography are the most common imaging modalities utilized in AD research. However, these techniques may or may not be feasible in primary care or neurologic clinical settings. Compared to plasma biomarker analysis, which is minimally invasive and nearing clinical implementation, ocular biomarkers remain primarily valuable in research investigations.