Quantitative Assessment of Microvascular Changes in Diabetic Retinopathy and Their Association With Blood-Retinal Barrier Impairment

Objective To quantitatively evaluate retinal microvascular changes in patients with diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA), and to explore their association with blood-retinal barrier (BRB) disruption.

Methods A total of 208 patients with type 2 diabetes and DR underwent OCTA to obtain microvascular parameters. Serum vascular endothelial growth factor (VEGF) and intercellular adhesion molecule 1 (ICAM-1) levels were measured. Correlations were analyzed, risk factors were identified using logistic regression, and diagnostic efficacy was evaluated with ROC curves.

Results The superficial capillary density (SCP-D) and deep capillary density (DCP-D) of the 208 DR patients were (42.67 ± 4.35)% and (47.89 ± 5.02)%, respectively. The mean values for the area, perimeter, and circularity index of the foveal avascular zone (FAZ) were (0.38 ± 0.10) mm², (2.04 ± 0.28) mm, and 0.72 ± 0.08, respectively. The mean area of the non-perfusion zone was (1.87 ± 0.45) mm². Among these patients, 121 (58.17%) cases had abnormal SCP-D (< 45%), 114 (56.25%) cases had abnormal DCP-D (< 50%), 88 (42.31%) cases had abnormal FAZ area, 77 (37.02%) cases had abnormal FAZ perimeter, 69 (33.17%) cases had abnormal FAZ circularity index, and 142 (68.27%) cases had abnormal non-perfusion zone area. The FAZ area was positively correlated with VEGF (r = 0.559, 95% CI: 0.457-0.661) and ICAM-1 (r = 0.411, 95% CI: 0.289-0.533). The FAZ circularity index, SCP-D, and DCP-D were negatively correlated with VEGF and ICAM-1 (P < 0.05). The area of the non-perfusion zone was positively correlated with both. Logistic regression showed that the duration of diabetes (odds ratio OR = 1.159, 95% CI: 1.060-1.267) and VEGF (OR = 1.013, 95% CI: 1.005-1.022) were independent risk factors for severe retinal microvascular changes (P < 0.05). Among the four OCTA assessment indicators, the area of the non-perfusion zone had the highest predictive value, with an area under the curve (AUC) of 0.879 (95% CI: 0.820-0.938).

Conclusion The OCTA assessment indicators in DR patients are closely related to BRB-related markers. The area of the non-perfusion zone has the highest predictive value for severe retinal microvascular changes in DR patients.