To evaluate the safety and efficacy of dexamethasone intravitreal implant (DEX implant; OZURDEX, Allergan, Inc., Irvine, CA) compared with sham in eyes with vision loss due to macular edema (ME) associated with branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO). Dexamethasone intravitreal implant can both reduce the risk of vision loss and improve the speed and incidence of visual improvement in eyes with ME secondary to BRVO or CRVO.