Single Site, Masked, Randomized, Controlled Study to Assess Efficacy of Osurdex as Adjunct to Avastin Compared With Avastin Alone in the Treatment of Patients With Macular Edema Due to Central or Branch Retinal Vein Occlusion

Inclusion Criteria: * male or female age 18 years or older * Branch retinal vein occlusion or central retinal vein occlusion of less than one year duration * Best correct visual acuity of greater than 24 and less than 80 * Presence of macular edema defined as OCT central subfield thickness of \>250 Exclusion Criteria: * intravitreal anti-VEGF treatment in study eye within six weeks of baseline * intravitreal steroid treatment in the study eye within eight weeks of baseline visit * PRP in the study eye within 4 month of baseline visit * Active iris neovascularization in study eye * Uncontrolled systemic disease * Known history of IOP elevation in response to corticosteroid treatment that is not controlled on 2 glaucoma medications