Decrease in the number of microaneurysms in diabetic macular edema after anti-vascular endothelial growth factor therapy: implications for indocyanine green angiography-guided detection of refractory microaneurysms

Purpose: We evaluated changes in the numbers of microaneurysms (MAs) on fluorescein angiography (FA) and indocyanine green angiography (IA) in eyes with diabetic macular edema (DME) following intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents. Methods: Twenty-one eyes of 16 patients with DME were included in this retrospective study. All patients received an initial loading dose of three monthly injections of anti-VEGF agents; thereafter, they received a pro re nata regimen for at least 12 months of follow-up. FA and IA images were obtained before and at 6 months after the initial injection. Results: The median numbers of MAs significantly decreased from six (interquartile range [IQR] 3–7) MAs in early-phase FA, three (IQR 3–5) leaky MAs in late-phase FA, and two (IQR 1–4) MAs in late-phase IA at baseline to two (IQR 1–3) MAs in early-phase FA, one (IQR 0–2) leaky MA in late-phase FA, and one (IQR 0–2) MA in late-phase IA at 6 months (P < 0.0001 for all). Only the median numbers of MAs in late-phase IA at baseline and at 6 months were significantly higher in the recurrent DME group (13 eyes) than in the non-recurrent DME group (five eyes) (three [IQR 2–4] vs one [IQR 1–2], one [IQR 0.5–2] vs zero [P = 0.0185 and P = 0.009]). Conclusion: Intravitreal injection of anti-VEGF agents reduced the numbers of MAs in patients with DME. The numbers of MAs detected by late-phase IA might be useful predictors of DME recurrence.