Retinal arteriovenous crossings as spatiotemporal stress fields: a quantitative Doppler OCT flowmetry study.

This study aimed to investigate the development of branch retinal vein occlusion (BRVO) from a hemodynamic stress perspective, rather than focusing solely on vascular morphology, and to identify parameters that may help assess risk at retinal arteriovenous (AV) crossings. Using Doppler optical coherence tomography, we quantified the interaction between structural compression and pulsatile flow at AV crossings, conceptualizing them as dynamic “spatiotemporal stress fields.” Venous hemodynamics were analyzed in healthy volunteers and patients with retinal vascular pathology to evaluate the biomechanical impact of arterial proximity. Arterial compression produced venous narrowing, flow acceleration, and asymmetric velocity profiles skewed toward the arterial side, resulting in localized shear stress imbalance. Wall shear stress (WSS) was calculated from velocity gradients derived from spatiotemporal asymmetric velocity profiles. In healthy eyes, venous WSS on the arterial side (1.42 ± 0.19 Pa) was higher than on the opposite side (0.90 ± 0.14 Pa). In contrast, crossings with a history of vascular pathology exhibited WSS values exceeding 3.0 Pa. These findings suggest that AV crossings function as biomechanical regulators where vascular geometry and flow distribution give rise to localized endothelial stress. Quantitative assessment of hemodynamic stress at AV crossings may provide a framework for evaluating BRVO risk before irreversible vascular damage occurs.