Quantitative Retinal Vascular Imaging Using Flood-Illuminated Adaptive Optics in Eyes with Lens Opacities

Flood-illuminated adaptive optics (AO) imaging enables high-resolution quantification of retinal vascular morphology; however, its repeatability in older adults with lens opacities remains poorly characterized. In this prospective study, 40 subjects (66 eyes) underwent flood AO imaging using the rtx1 system (Imagine Eyes, Orsay, France) at three retinal locations across multiple sessions. Two independent masked graders measured lumen diameter (LD), total diameter (TD), wall cross-sectional area (WCSA), and wall-to-lumen ratio (WLR), with repeatability assessed using intraclass correlation coefficients (ICC). Inter-grader agreement was excellent for LD and TD across all regions (ICC range 0.974-0.994) and for WCSA at the superior and inferior regions (ICC range 0.902-0.952). Intrasession and intersession repeatability were similarly excellent for LD and TD across all locations. Repeatability remained excellent across age groups and cataract grades. Image region was the only variable significantly associated with image quality (p < 0.0001), with temporal images showing the lowest proportion of good quality ratings (12%). These findings support flood AO imaging as a reliable tool for quantitative vascular assessment in age-related and vascular-related ocular diseases.