The Impact of Interval between Recurrence and Reinjection in Anti-VEGF Therapy for Diabetic Macular Edema in Pro Re Nata Regimen

Background: Pro re nata (PRN) regimen using anti-vascular endothelial growth factor (VEGF) agent is popular for the treatment of diabetic macular edema (DME). We investigated the influence of waiting time (WT) and interval between the date of recurrence of edema and re-injection on treatment efficacy. Methods: This retrospective study conducted at 7 sites in Japan enrolled patients who received intravitreal injection of ranibizumab (IVR) and aflibercept (IVA) in 1+PRN regimen. Enrolled patients were divided into 2 groups: prompt group (less than 1 week) and deferred group (3 weeks or more). Central retinal thickness (CRT) and best corrected visual acuity (BCVA) were measured every month for 1 year. Results: CRT in the deferred group was significantly higher than that in the prompt group at 2, 5, 6, 7, and 12 months (p < 0.05). BCVA in the prompt group was significantly better than that in the deferred group at 7, 10, and 12 months (p < 0.05). Conclusion: The prompt group was superior in anatomical and functional improvement of DME in anti-VEGF therapy than the deferred group. Our data suggests that shorter WT is recommended for better visual prognosis in the treatment for DME.