Vortex vein location as an individualized marker of anatomic retinal far periphery using non-steered ultrawide field fluorescein angiography.

Abstract

Purpose : To compare location of the anatomic retinal far periphery (FP) using vortex vein location on ultrawide field color imaging (UWF-CI) with UWF fluorescein angiography (UWF-FA) and standard 15mm fovea-centered circles.

Methods : 18 eyes of 18 diabetic patients with no retinopathy were selected for image quality and same-day UWF-CI and UWF-FA. On-axis UWF-FA was assessed by 2 graders for FP location based on presence of unilaminar peripheral vascular structure, previously confirmed in vascular cast studies. Distance from optic disc center to the most peripheral vortex vein lumen was measured in all UWF-CI quadrants and a circle with this mean radius was centered on the nerve (VXcircle). Using UWF-FA, the distance between optic nerve center and the most posterior extent of the anatomic FP was assessed at 3, 6, 9 and 12 o’clock and a circle with this mean radius was centered on the optic disk (FAcircle). Intra/inter grader agreement (Jaccard index; JI) for VXcircle, FAcircle and the 15 mm fovea-centered Circle (STDCircle) were compared.

Results : The FP was not visualized in the superior or inferior quadrant in any eye, was not evident nasally in 8 eyes (44.4%), and was only partially observed in the others. Temporal FP was visualized to the peripheral avascular retina in all eyes. Mean radii of the FAcircles and VXcircles were 14.98±1.40 mm and 15.23±0.65mm, respectively (p=0.40). Compared to the FAcircles, the STDCircles were displaced temporally 3.94 mm and over-estimated the extent of the nasal FP area in all eyes (79.10±13.60 mm² vs 36.91±10.52 mm², p<0.001). Intergrader JI was 0.91±0.06 (VXCircles) and 0.77±0.10 (FAcircles). Intragrader JI for FAcircles vs VXCircles was 0.81±0.07 and 0.79±0.10, average = 0.80±0.09. The JI between STDCircles and FAcircles was 0.69±0.01, significantly lower than the JI between VortCircles and FAcircles (0.80±0.03, p<0.001).

Conclusions : While circle diameter does not differ significantly between FAcircles, VortCircles and the 15mm radius circle, circle location differs substantially. The vortex-vein measure appears reproducible and provides a more individualized and anatomically accurate method of identifying FP retina than the standard 15mm circle. Studies evaluating non-perfusion and lesions of the retinal far periphery should consider utilizing vortex vein markers to optimize anatomic accuracy and reproducibility

This is a 2020 ARVO Annual Meeting abstract.