This study used two imaging methods to evaluate retinal nonperfusion after anti-VEGF treatment for diabetic macular edema.

Study design

This observational case series included 10 eyes (9 patients) with severe nonproliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR). Researchers assessed changes in retinal nonperfusion using swept-source widefield OCT angiography and ultra-widefield fluorescein angiography (FA). All eyes were imaged at baseline and 1 month after the third anti-VEGF injection. Images were divided into 16 boxes and analyzed by two masked retina specialists.

Outcomes

Eight eyes experienced an improvement in diabetic retinopathy severity score by at least 1 stage. Color fundus photographs showed that these eyes had a significant reduction in the average number of microaneurysms and retinal hemorrhages at 1 month (P = 0.002) and regression of fundus neovascularization, when present.

Although both techniques detected the same areas of nonperfusion, OCT detected additional areas in 29% of boxes at baseline. Neither method detected reperfusion of arterioles or venules at 3 months. Retinal capillaries were only visible on OCT. Reperfusion of nonperfusion areas were not observed, even when reduced dark areas were visible on FA.

Limitations

The study had a small sample size and short follow-up. Neither imaging technique detected reperfusion of vessels or capillary areas after anti-VEGF.

Clinical significance

Swept-source widefield OCT angiography had a higher detection rate of nonperfusion area than FA. Since neither OCT angiography nor FA showed improvement in areas of nonperfusion after 3 anti-VEGF injections, this suggests that anti-VEGF treatment may be a chronic, long-term therapy in patients with diabetic retinopathy.