Intravitreal Ranibizumab to Treat Macular Edema After Panretinal Photocoagulation (Phase II)

Inclusion Criteria: * Pre-PRP protocol refraction, fluorescein angiography, and optical coherence tomography AND 7-14 day post-PRP OCT * Ability to provide written informed consent and comply with study assessments for the full duration of the study * Age 21 years or older * Previously untreated PDR patients with high risk characteristics who develop edema within 7-14 days post PRP therapy. This edema, determined by a masked investigator, will be characterized as either increased foveal thickness (\>10% increase from pre-PRP foveal thickness), and/or increased macular volume on OCT (\>10% increase from pre-PRP macular volume). Exclusion Criteria: * Pregnancy (positive pregnancy test) prior to enrollment in the study * Any other condition that the investigator believes would pose a significant hazard to the subject if the investigational therapy were initiated. * Participation in another simultaneous medical investigation or trial * Pre-PRP clinically significant diabetic macular edema (CSME) that would make the patient eligible for macular laser prior to PRP * Neovascularization of the iris or neovascular glaucoma * Increased central foveal thickness for any other reason * Concurrent macular diseases that could confound the results of this study * Prior vitrectomy in the study eye * Prior treatment with intravitreal injection including pegaptanib sodium, ranibizumab, bevacizumab or triamcinolone acetonide