Diabetic Ischemia Shows Both Capillary Nonperfusion and Restored Perfusion

These images from the study show loop vessel formation in a 42-year-old male patient with PDR. The en face OCT-A images show the superficial layer at baseline (A) and at three years (B). In (C), the images are merged (green = baseline; red = three years) and (D) show a magnified image of the square in panel C with detail of a newly formed loop vessel. Photo: Yoshida M, et al. Transl Vis Sci Technol. June 17, 2026. Click image to enlarge. Recent advances in OCT angiography (OCT-A) have enabled three-dimensional visualization of retinal vasculature and quantitative assessment of capillary nonperfusion, given the technology’s higher-contrast, layer-by-layer images compared to fluorescein angiography. This is providing a more nuanced understanding of diabetic macular ischemia. A new study conducted in Japan investigated longitudinal changes in capillary perfusion in patients with diabetic retinopathy (DR) using OCT-A. The team and found restored capillary perfusion in some eyes with DMI, suggesting revascularization and reperfusion. The findings were reported in Translational Vision Science & Technology.The researchers prospectively analyzed 106 eyes over a three-year period to assess capillary perfusion status. Qualitative assessment identified OCT-A 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.While total nonperfusion increased in the superficial layer for most eyes, sector-based analyses revealed that some eyes experienced a reduction in nonperfusion—i.e., restored capillary perfusion. “Reduced capillaries induce retinal hypoxia and subsequent expression of vascular endothelial growth factor, which may promote intraretinal revascularization as in the case of retinal neovascularization,” the authors wrote in their paper. “In addition, unstable blood flow may also contribute to vascular reperfusion.” Specific morphological patterns on OCT-A images suggestive of intraretinal revascularization and reperfusion were identified:rod-like vessels: straight vessels with uniform caliberbulb signs: newly developed vessels with distal enlargementloop vessels: vessels forming irregular or circular loopsvessel reappearance: line-like flow signals connecting to the ends of pre-existing vessels, suggesting reperfusion“In particular, rod-like vessels and bulb signs were more frequently observed outside the FAZ than within it in the superficial layer,” the authors explained in their paper. “We may speculate that progression of capillary nonperfusion is more rapid than restored perfusion in these areas.”Newly developed vessels frequently extended into the FAZ or parafoveal nonperfused areas. “Rod-like vessels could correspond to linear extensions of revascularization within the retinal parenchyma and appear as vascular tubes composed of stalk cells,” the authors wrote. “The bulb sign resembles a saccular microaneurysm and may represent the initial budding of revascularization or endothelial proliferation without migration owing to repulsive signaling.” Some of these vessels may reach and anastomose with adjacent vessels to form loop vessels, the paper describes. “In conclusion, this study revealed opposing changes—progressive capillary nonperfusion and restored capillary perfusion,” the authors wrote, “which may enhance our understanding of the underlying vascular pathophysiology.”Click here for the journal source. Yoshida M, Murakami T, Ishihara K, et al. Qualitative and quantitative assessment of restored capillary perfusion on OCT Angiography in diabetic macular ischemia. Transl Vis Sci Technol. June 17, 2026. [Epub ahead of print.] This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.