This study examines two doses of Ranibizumab (0.5mg and 1.0mg) for the treatment of macular edema secondary to retinal vein occlusion in patients that have previously failed treatment with other macular edema treatments including bevacizumab.

Inclusion Criteria:

• Ability to provide written informed consent and comply with study assessments for the full duration of the study
• Age > 18 years
• CRVO or BRVO diagnosis
• For CRVO, clinical evidence of perfused central retinal vein occlusion. A CRVO is defined as an eye that has retinal hemorrhages and a dilated retinal venous system in all 4 quadrants. Other evidence of a CRVO may include telangiectatic capillary bed and collateral vessels at the optic nerve head.
• Central macular edema present on clinical examination and OCT testing with a central point thickness and/or central 1mm subfield thickness > 300 microns after at least 3 months of bevacizumab or steroid therapy.
• Visual acuity score greater than or equal to 19 letters (20/400) and less than or equal to 73 letters (20/40) by the ETDRS visual acuity protocol.
• Patients must demonstrate that they are no longer improving on bevacizumab or intravitreal steroid therapy (i.e. no improvement in acuity in 2 consecutive visits)
• BRVO patients treated with grid laser must show residual edema three months following latest laser treatment
• Media clarity, pupillary dilation and patient cooperation sufficient to allow OCT testing and retinal photography

Exclusion Criteria:

• Pregnancy (positive pregnancy test) or known to be pregnant; also pre-menopausal women not using adequate contraception.
• Participation in another ocular investigation or trial simultaneously
• Any condition that, in the opinion of the investigator, would preclude participation in the study (e.g. chronic alcoholism, drug abuse)
• Significant diabetic retinopathy (greater than moderate NPDR) or macular edema associated with diabetic retinopathy
• An eye that, in the investigator's opinion, has no chance of improving in visual acuity following resolution of macular edema (e.g. presence of subretinal fibrosis or geographic atrophy or severe epiretinal membrane)
• Presence of another ocular condition that may affect the visual acuity or macular edema during the course of the study (e.g. AMD, uveitis, Irvine-Gas)
• Evidence of neovascularization of the iris or retina (presence of ischemic CRVO/BRVO)
• Evidence of central atrophy or fibrosis in the study eye
• Presence of substantial cataract, one that might decrease the vision by 3 or more lines of vision at sometime during the study.
• History of grid/focal laser or panretinal laser in the study eye in the previous three months
• History of vitreous surgery in the study eye
• History of use of intravitreal, peribulbar, or retrobulbar steroids within three months of the study.
• History of cataract surgery within 6 months of enrollment.
• History of YAG capsulotomy within 2 months of the surgery.
• Visual acuity <20/400 in the fellow eye
• Uncontrolled glaucoma (pressure >30) despite treatment with glaucoma medications.
• History of cerebral vascular accident or myocardial infarction within 3 months prior to Day 0.