Objective To evaluate the safety and efficacy ofdexamethasone intravitreal implant 0.7 mg (DEX) for treatment of macular edema associated with retinal vein occlusion (RVO).Methods This study was a six-month,randomized,double-masked,sham-controlled,multicenter,phase 3 clinical trial with a 2-month open-label study extension.Patients with branch or central RVO received DEX (n=129) or sham procedure (n=130) in the study eye at baseline;all patients who met re-treatment criteria received DEX at month 6.Efficacy measures included Early Treatment Diabetic Retinopathy Study (ETDRS),best-corrected visual acuity (BCVA),and central retinal thickness (CRT) on optical coherence tomography.Results Time to ＞ 15-letter BCVA improvement from baseline during the first 6 months (primary endpoint) was earlier with DEX than sham (P＜ 0.001).At month 2 (peak effect),the percentage of patients with ≥ 15-letter BCVA improvement from baseline was DEX:34.9％,sham:11.5％;mean BCVA change from baseline was DEX:10.6± 10.4 letters,sham:1.7 ± 12.3 letters;and mean CRT change from baseline was DEX:-407 ± 212 μm,sham:-62 ± 224 μm (all P＜0.001).Outcomes were better with DEX than sham in both branch and central RVO.The most common treatment-emergent adverse event was in-creased intraocular pressure (IOP).Increase sin IOP generally were controlled with topical medication.Mean IOP normalized by month 4,and no patient required incisional glaucoma surgery.Conclusions DEX had a favorable safety profile and provided clinically significant benefit in a Chinese patient population with RVO.Visual and anatomic outcomes were improved with DEX relative to sham for 3-4 months after a single implant.