The effect of intravitreal dexamethasone implantation on diabetic macular edema refractory to anti-vascular endothelial growth factor treatment

Purpose: To evaluate the efficacy and safety of intravitreal dexamethasone (DEX) implantation for diabetic macular edema (DME) that proved unresponsive to previous anti-vascular endothelial growth factor (VEGF) treatment. Methods: This prospective interventional study recruited 91 patients with refractory DME after previous anti-VEGF treatments in one or both eyes. All patients were followed up for at least 12 months. Best-corrected visual acuity (BCVA), central subfield thickness (CST) and macular volume were measured. Results: Over the 12 months, a mean of 2.1 ± 0.8 DEX implantations were administered per eye; 26 eyes (28.9%) received 1 implantation, 31 (34.4%) received 2, and 34 (36.7%) received 3. BCVA was significantly improved in the first 6 months, from 54.8 to 59.5 letters. Both CST and macular volume decreased significantly after DEX implantation and maintained these improvements for at least 12 months. Subjects who needed the second DEX implantation had a greater number of prior anti-VEGF injections than did those who needed only one implantation (6.0 vs 3.0). Conclusions: Two-thirds of refractory DME required less than two DEX implantations to maintain a dry macula for 12 months. Early switching to intravitreal DEX can be considered as the second-line therapeutic option, especially during the COVID-19 pandemic.