The Utility of Optical Coherence Tomography Angiography Biomarkers in Detecting Diabetic Retinopathy.

PURPOSE: To evaluate associations between optical coherence tomography angiography (OCT-A) metrics and diabetic retinopathy (DR) and compare their discrimination against conventional clinical risk factors.

METHODS

In this cross-sectional study, 108 adult eyes with diabetes were recruited from tertiary ophthalmology/optometry clinics. DR was clinically graded using ETDRS categories and dichotomised as no DR vs ≥ mild NPDR (primary outcome). Macular 6 × 6 mm OCT-A (Zeiss AngioPlex™) was acquired; scans with signal strength > 7 and without major artefact were included. Quantitative metrics from the superficial capillary plexus included vessel density (VD) and perfusion density (PD) (central/inner/outer/full regions); structural OCT measures and FAZ parameters were secondary. Associations with ≥mild NPDR were assessed using multivariable logistic regression adjusted for age, sex, HbA1c, and diabetes duration. Discrimination was evaluated with ROC curves/AUC (95% CI) and DeLong comparisons of AUCs.

RESULTS

≥Mild DR was present in 63% of eyes. DR was associated with lower VD (central, inner, outer, full) and lower PD (central, inner, full) (all p ≤ 0.04). After adjustment, central VD (OR 0.82, 95% CI 0.68-0.98) and central PD (OR 0.92, 95% CI 0.86-0.99) remained independently associated with DR. The OCT-A model showed moderate discrimination compared to the clinical model (AUC 0.72 vs 0.65); the combined model yielded AUC 0.75.

CONCLUSION

Central VD and PD from the superficial plexus are independently associated with DR and show moderate discrimination versus conventional clinical factors alone, supporting OCT-A as an adjunctive biomarker for earlier DR detection.