Qualitative and Quantitative Assessment of Restored Capillary Perfusion on OCT Angiography in Diabetic Macular Ischemia.

PURPOSE: The purpose of this study was to investigate characteristics of restored capillary perfusion on optical coherence tomography angiography (OCTA) in diabetic retinopathy (DR).

METHODS

We prospectively obtained OCTA images from 106 eyes of 106 patients with DR and analyzed them within a 2.5-mm-diameter circle. The area was divided into 15 × 15-pixel squares; those without vascular edge signals were defined as nonperfusion squares (NPSs) at baseline and 3 years after image registration. Qualitative assessment identified OCTA findings representing restored perfusion: newly developed uniform-caliber vessels ("rod-like vessels"), vessels with distal enlargement ("bulb sign"), loop-forming vessels ("loop vessel"), and "vessel reappearance" suggestive of reperfusion.

RESULTS

In the superficial layer, eyes with advanced diabetic macular ischemia (DMI) showed NPS reduction in the central subfield more frequently than those with mild DMI (P < 0.001). Baseline NPS counts were negatively correlated with 3-year NPS changes in the central sector of the superficial and deep layers (P < 0.05). In the deep layer, NPS reduction in the parafoveal sectors was observed more frequently in eyes with advanced DMI (P < 0.05). Qualitative assessment showed rod-like vessels, bulb signs, loop vessels, and vessel reappearance in 81, 75, 11, and 93 eyes, respectively. Rod-like vessels and bulb signs were more frequently observed outside the foveal avascular zone (FAZ) than within it in the superficial layer (P < 0.001 for both comparisons).

CONCLUSIONS

Quantitative and qualitative analyses demonstrated restored capillary perfusion on OCTA in some eyes with DMI, suggesting revascularization and reperfusion.

TRANSLATIONAL RELEVANCE: Advanced DMI exhibits both progressive capillary nonperfusion and restored capillary perfusion on OCTA.