Retinal neurovascular coupling evaluation with circular-scan OCTA.

Neurovascular coupling (NVC) is the mechanism by which neuronal activity regulates blood flow. Detection of abnormalities in NVC may be clinically useful as they could signal early retinal dysfunction before structural damage becomes apparent. While optical coherence tomography angiography (OCTA) enables high-contrast, non-invasive functional imaging of the retina, its conventional form cannot detect light-evoked hemodynamic responses, which are the key indicators of NVC. Visualizing and quantifying NVC-driven hemodynamics in the human retina remains challenging due to motion artifacts and insufficient temporal resolution. To overcome these limitations, we developed a functional OCTA prototype integrated with a green light stimulus that reliably triggered NVC. The OCTA prototype was built with off-the-shelf optics and a 200-kHz A-line rate laser to assess NVC in vivo with a circular-scan pattern to improve the temporal resolution and reduce motion artifacts. We present NVC response curves and statistical analyses across multiple vascular plexuses in healthy eyes, demonstrating the system's potential for both clinical translation and advancing early diagnosis of retinal diseases.