Retinal Ischemic Perivascular Lesions Screen for Vision-Threatening Diabetic Retinopathy Visualized on...

To validate retinal ischemic perivascular lesions (RIPLs) as an optical coherence tomography (OCT) biomarker for vision-threatening diabetic retinopathy (VTDR), using ultra-widefield fluorescein angiography (UWF-FA) as the grading reference.

This retrospective cohort study included 76 patients (97 eyes) with diabetic retinopathy (DR), who underwent same-day UWF-FA and OCT at Northwestern Memorial Hospital. DR severity was graded on UWF-FA. RIPLs were identified on a per-lesion basis using 61 serial B-scans from Heidelberg SPECTRALIS OCT (30° × 25° field of view). RIPLs were defined as thinning of the inner nuclear layer, disruption of the outer plexiform layer, and elevation of the outer nuclear layer. Two independent graders assessed the RIPL counts, and the intraclass correlation coefficient (ICC) was calculated. Associations between RIPL count and VTDR were evaluated using generalized estimating equation models clustered by patient. Receiver operating characteristic (ROC) analysis assessed diagnostic performance.

Fifty-three eyes were graded as VTDR (54.6%) and 44 eyes as non-VTDR (45.4%). Median RIPL counts were 0 in non-VTDR and 4 in VTDR eyes. The ICC was 0.974 (95% confidence interval [CI], 0.949-0.986). Each additional RIPL increased the odds of having VTDR by 22% (95% CI, 1.09-1.37; P = 0.001). ROC analysis yielded an area under the curve of 0.813 (95% CI, 0.730-0.897), with an optimal threshold of 2.5 RIPLs having a sensitivity of 70% and specificity of 84% for detecting VTDR.

RIPL count is a reproducible OCT biomarker for VTDR, validated against UWF-FA using low-density OCT scans.

RIPLs offer a quantitative and practical OCT-based biomarker to identify diabetic patients at high risk for vision loss.