Circumferential multi-contrast mapping of the aqueous outflow pathway in human eyes facilitated by circular-scan optical coherence tomography angiography

The corneoscleral limbus contains essential aqueous channels and veins that form the primary aqueous outflow pathway, making it a critical focus of glaucoma research. Optical coherence tomography (OCT) has emerged as a powerful tool for investigating this pathway, but conventional imaging is typically performed in segments and restricted to a single functional contrast. Such approaches are limited in evaluating the overall condition of the outflow system, which contributes circumferentially asymmetrically to the aqueous outflow and is composed of multiple tissues requiring different OCT functional extensions. To address these limitations, we propose a circumferential, multi-contrast mapping framework for in vivo analysis of limbal vasculature and aqueous outflow structures/functions. The workflow begins with a rapid panoramic OCT angiography scan using a circular-scan anterior segment OCT (CircAS-OCT) system to generate a global limbal reference map. This reference is then used to guide the stitching of sectional scans acquired from high-resolution OCT devices and protocols. In two normal subjects, the method successfully enabled circumferential, multi-contrast mapping of selected outflow-related structures and processes, including depth-resolved limbal vasculature, collector channel orifice positions, trabecular meshwork regions, and trabecular motion strength, with results aligning well with established anatomical knowledge. By combining circumferential coverage and cross-function integration, our approach provides a versatile imaging platform with strong potential for comprehensive assessment of the aqueous outflow pathway, supporting diagnostic and surgical strategies in glaucoma management.