Progress of Diabetic Macular Edema after Loading Injection of Anti-Vascular Endothelial Growth Factor Agents in Real-World Cases

Background and Objectives: To evaluate the recurrence of diabetic macular edema (DME) after loading an injection of anti-VEGF agents by a pro re nata (PRN) protocol using central retinal thickness (CRT) as a re-injection criterion. Materials and Methods: This is a retrospective, observational single-center study. DME patients with a central retinal thickness (CRT) over 350 μm received a PRN injection of anti-VEGF agents following one to three consecutive monthly loading injections (bevacizumab, ranibizumab, and aflibercept) for 6 months from January 2012 to June 2019. Results: We enrolled a total of 72 eyes for loading injections and the mean CRT improved from 434.04 ± 139.4 μm (before treatment) to 362.9 ± 125.0 μm after the loading injection. One week after injection, 36 eyes (50%) obtained a CRT of ≤350 μm. Fourteen eyes (19.4%) remained with a CRT of ≤350 μm for 6 months without additional injections. A total of 22 eyes (30.6%) had a CRT of >350 μm at 6 months. Fifteen eyes did not receive additional injections because of visual improvement. Conclusions: About 20% of DME patients can be maintained at a CRT of ≤350 μm for 6 months with only a loading injection. However, there is a tendency to delay additional injections for patients with recurrences using PRN protocol.