Objective: To investigate the visual acuity and anatomical outcomes of intravitreal aflibercept treatment in patients with diabetic macular edema (DME) who were unresponsive to ranibizumab.

Methods: Patients with refractory DME treated with at least 3 consecutive injections of ranibizumab, 4-6 weeks apart, before switch and with at least 2 aflibercept injections after that in the period of May 2013 to October 2017 were considered eligible for study participation. “The patients” demographic characteristics, best-corrected visual acuity (BCVA), and central foveal thickness (CFT) were recorded at baseline, pre-switch, the first month post-switch, and the final visit.

Results: A total of 33 eyes of 28 patients were investigated. The average number of ranibizumab injections before switching to aflibercept was 4.97±1.94 and that of the subsequent aflibercept injections was 2.54±0.6. The mean baseline BCVA was 0.56 ± 0.38 logMAR. After the switch, the BCVA during the first and final visits was 0.41±0.34 logMAR (p=0.19) and 0.36±0.34 (p=0.16), respectively. After switching, clinical follow-up data for at least 6 months were available for all eyes. The mean baseline CFT was 504±123.7 µm (264-844 µm).One month after the switch, the average CFT had significantly reduced to 338.8±105.3 µm (225-615 µm) (p=0.0001). At the final visit, the average CFT was 345.7±137.4 µm (136-892 µm) (p=0.0002). Before and after the switch, the mean intraocular pressure (IOP) was 14.18±3.66 mmHg and 13.54±3.81 mmHg respectively (p=0.46).

Conclusion: Switch to aflibercept from ranibizumab in patients with recalcitrant DME resulted in significant anatomical improvements. Although the BCVA increased and the IOP decreased, these changes were not statistically significant.