Retinal Neurovascular Coupling: From Mechanisms to a Diagnostic Window into Brain Disorders.

Retinal neurovascular coupling reflects the precise coordination between neuronal activity, glial support, and vascular responses, mirroring key neurovascular mechanisms in the brain. This review emphasizes the cellular and molecular processes underlying retinal neurovascular coupling and positions the retina as a sensitive and accessible model for investigating neurovascular function in the brain. It highlights how parallel neurovascular degeneration in the brain and retina provides critical insights into the pathophysiology of neurodegenerative and vascular disorders. Advances in retinal imaging, including functional optical coherence tomography (fOCT), OCT angiography (OCTA), and functional electrophysiology, offer unprecedented opportunities to detect early neuronal and vascular dysfunction, establishing the retina as a non-invasive biomarker for early detection, disease monitoring, and therapeutic evaluation in Alzheimer's, Parkinson's and Huntington's disease, and stroke. By integrating structural, functional, and mechanistic approaches, the review emphasizes the retina's potential as a translational platform bridging basic science and clinical applications in neurovascular research.