To test the efficacy of a 0.7 mg intravitreal dexamethasone implant (Ozurdex®) on macular function and recalcitrant macular edema associated with retinal vein occlusion following treatment with 2 or more prior intravitreal anti-VEGF drug injections.

The efficacy of the DEX implant on macular edema for RVO is well established in multiple clinical trials. However, the duration and frequency of re-treatment have not been extensively explored. In addition, no prior studies have tested the efficacy of the DEX implant on retinal and macular function using diagnostic testing measurements such as multi-focal ERG, microperimetry and RAM testing. Since VA and OCT outcomes do not always correlate, these other assessments (mf-ERG, microperimetry, RAM testing) may be useful as early predictors of when or if patients should be retreated. This study will assess 2 groups (0.7mg PRN and 0.7mg Q16 weeks) and assess high resolution OCT, RAM testing, microperimetry, and Multi-focal ERG outcomes. For the PRN group retreated based on any fluid on OCT, we will investigate if microperimetry or multifocal ERG changes would have been an earlier predictor of fluid returning.

Inclusion Criteria:

• Presence of central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO)
• Prior treatment with >= 2 intravitreal anti-VEGF injections but no treatment in last 45 days.
• Age 18 years or older
• ETDRS Visual acuity between 3 and 72 letters and approximate Snellen equivalent of 20/25 to 20/800
• Central foveal thickness >275 microns or presence of cystic edema on OCT studies.
• For sexually active women of childbearing potential, agreement to the use of an appropriate form of contraception (or abstinence) for the duration of the study.
• Ability to provide written informed consent • Capable of complying with study protocol

Exclusion Criteria:

• History of steroid-related glaucoma (steroid response) requiring more than one topical glaucoma medication.
• Intraocular injection of steroid medication within prior 4 months
• Evidence of significant retinal ischemia on fluorescein angiography in the opinion of the treating physician.
• Previous laser photocoagulation within 4 months of study
• Concurrent ocular disease (e.g proliferative diabetic retinopathy, geographic atrophy) that would limit visual acuity in the opinion of the treating physician
• Patients who are pregnant.
• Unwilling or unable to follow or comply with all study related procedures.