AIM: To investigate the efficacy of dexamethasone implant injection in the treatment of persistent diabetic macular edema(DME).METHODS: The clinical data of 30 DME patients(30 eyes)after anti-vascular endothelial growth factor(anti-VEGF)agents from June 2019 to January 2020 were retrospectively analyzed. All patients had underwent intravitreal injection of DEX. Best corrected visual acuity(BCVA), intraocular pressure(IOP), central macular thickness(CMT)and adverse events were recorded.RESULTS:BCVA(LogMAR)was significantly improved from(0.86±0.47)to(0.57±0.53, 0.42±0.48, 0.43±0.26, 0.45±0.66 and 0.51±0.37)at 1, 2, 3, 4 and 6mo after treatment. CMT improved significantly from baseline(495.64±107.23)μm to(412.57±74.55, 370.21±23.83, 371.53±52.66, 373.28±68.49, 389.35±95.61)μm 1, 2, 3, 4 and 6mo post-injection. The drug reached its peak efficacy 2mo after administration. 4 eyes were given repeated injection at 3mo, 5 eyes were given at 5mo and 2 eyes were given at 6mo following the primary injection. Cataract progression was showed in 1 case. 4 patients demonstrated IOP levels above 22mmHg and were mostly controllable by IOP-lowering medications. None of patients showed any adverse events at 6mo of follow-up.CONCLUSION: Dexamethasone implant injection showed significant BCVA and CMT improvement. DEX injection may be utilized as an effective DME therapy for patients who are persistent after anti-VEGF treatment.