Region-specific choroidal vascular alterations in diabetes revealed by ultra-wide-field swept-source OCTA.

PURPOSE: To compare choroidal vascular alterations using ultra-wide-field swept-source optical coherence tomography angiography (UWF-SS-OCTA) between diabetic eyes and control eyes, and to evaluate their associated factors and diagnostic relevance.

METHODS

UWF-SS-OCTA (24 × 20 mm) was performed in non-diabetic controls (NDM), diabetic patients without retinopathy (NDR), and patients with non-proliferative diabetic retinopathy (NPDR). The scan area was divided into nine regions. Choroidal vascularity index (CVI), choroidal vascular volume per unit area (CVV/a), choroidal stromal volume per unit area (CSV/a), and choroidal stromal index (CSI) were compared among groups. Associations with clinical variables were analysed, and diagnostic performance was assessed using receiver operating characteristic analysis.

RESULTS

Mean CVI was significantly reduced in diabetic eyes, including NDR, compared with controls. The nasal-superior region showed the most pronounced reductions in CVI, CVV/a, and CSV/a. These parameters were negatively associated with age and independently influenced by diabetic status. CVI and CVV/a demonstrated good discrimination between diabetic and non-diabetic eyes but did not distinguish NDR from NPDR.

CONCLUSION

Region-specific choroidal vascular impairment occurs early in diabetes. Nasal-superior CVI and CVV/a may serve as non-invasive biomarkers of early diabetic choroidopathy.