To compare the efficacy of intravitreal dexamethasone implant according to previous responses to Bevacizumab treatment in patients with macular edema (ME) secondary to branch retinal vein occlusion (BRVO).

Sixty eyes of 60 patients who received an intravitreal dexamethasone implant for ME secondary to BRVO and followed up for at least 6 months were retrospectively reviewed. Of these, 31 patients were treatment naïve and 29 patients had previously received intravitreal injection of anti-vascular endothelial growth factor (VEGF). Out of these previously-treated patients, 17 patients were categorized as a refractory group who did not respond to previous injection and 12 patients were categorized as a responder group who showed recurrent ME despite a good response to previous anti-VEGF treatment. The best corrected visual acuity (BCVA), central macular thickness (CMT) and recurrence of ME were assessed monthly for 6 months.

At each 3-month follow-up, the BCVA improved significantly from baseline in the naïve group, while the refractory group and the responder group showed significant improvement for only 2 months. At each 3-month follow-up, the CMT showed significant decreases in every group. However, the mean change in CMT from baseline showed significant differences between the 3 groups at month 3 ( p < 0.001). During follow-up, 18 eyes in the naïve group (58.1%), 16 eyes in the refractory group (94.1%), and 6 eyes in the responder group (50.0%) received retreatment for the recurrence of ME, and there was a significant difference in the retreatment rate between the three groups ( p = 0.016).

Intravitreal dexamethasone implant showed early good functional and anatomical improvements irrespective of the response to the previous treatment in patients with ME secondary to BRVO. However, when treating the refractory group, more careful observation and intensive retreatment are required, considering the short duration of its efficacy.