Evaluation of Vascular Biomarkers in Diabetic Retinopathy Using Ultrawide-Field Swept-Source Optical Coherence...

To quantify nonperfusion areas (NPA) and intraretinal microvascular abnormalities (IRMAs) and evaluate their diagnostic performance in diabetic retinopathy (DR) using ultrawide-field (UWF) swept-source optical coherence tomography angiography (SS-OCTA).

In this cross-sectional study, nonperfusion index (NPI) and IRMA counts were analyzed on single-capture 29 × 24 mm optical coherence tomography angiography (OCTA) images. Regional analyses across the central zone (CZ), intermediate zone (IZ), and outer zone (OZ) were performed. Area under the receiver operating characteristic analysis evaluated the ability of regional and total metrics to discriminate DR severities.

A total of 165 eyes from 120 patients (73 male; mean age, 57.0 ± 11.1 years) across DR severities were included. Total NPI and IRMA counts increased with advancing DR severity (P < 0.001). NPI increased significantly from CZ to IZ across all DR stages (P < 0.001), with further extension into OZ in proliferative DR (PDR) (P < 0.001). IRMA counts were highest in the IZ in moderate nonproliferative DR (NPDR), severe NPDR, and PDR (P < 0.001). OZ NPI performed comparably with total NPI for distinguishing PDR from NPDR (area under the receiver operating characteristic, 0.88 vs. 0.86; P = 0.21), whereas IZ NPI and IRMA counts performed comparably with their respective total field measurements for distinguishing advanced DR from early DR (NPI, 0.95 vs. 0.95 [P = 0.83]; IRMA, 0.86 vs. 0.89 [P = 0.12]).

Single-capture UWF SS-OCTA supports a regional biomarker framework for DR. More peripheral ischemia may add value for identifying neovascular transformation, whereas imaging extending into the intermediate retina may retain useful diagnostic value for distinguishing advanced from early DR when full UWF imaging is unavailable.