Ranibizumab For Persistent Diabetic Macular Edema After Bevacizumab

Inclusion Criteria: * Ability to provide written informed consent and comply with study assessments for the full duration of the study. * \>=18 years * Type I/II diabetes mellitus * Central-involved DME in study eye (OCT CSF \>=275um on Heidelberg Spectralis spectral domain OCT with evidence of intraretinal or subretinal fluid or cysts) * Definite retinal thickening due to diabetic macular edema involving the center of the macula. * Media clarity, pupillary dilation and individual cooperation for adequate fungus photography and fluorescein angiography. * Visual Acuity score in study eye \<=80 and \>=20 (approximate Snellen equivalent 20/25 to 20/400). * History of at least 6 intravitreal bevacizumab injections within the past 9 months and 2 intravitreal bevacizumab injections within the past 2 months. * No history of an anti-VEGF treatment for DME in the past 3 weeks. * No other DME treatment for DME, other than bevacizumab, in the study eye at any time in the past 3 months. * No history of major ocular surgery in the study eye within prior 3 months or anticipated within the next six months following randomization. Exclusion Criteria: * Pregnancy or lactation * Any other condition that the investigator believes would pose a significant hazard to the subject if the investigational therapy were initiated * Participation in another medical investigation or trial within 30 days of randomization * Known allergy to ranibizumab * Acute cardiovascular event requiring hospitalization within the past 3 months * Systemic anti-VEGF or pro-VEGF treatment within 3 months prior to randomization or anticipated use during the study * Macular edema is considered to be due to a cause other than DME * An ocular condition is present such that, in the opinion of the investigator, visual acuity loss would not improve from the resolution of macular edema * History of intravitreal anti-vascular endothelial growth factor (anti-VEGF) agent other than bevacizumab within 9 months prior to randomization * History of panretinal photocoagulation within 3 months prior to randomization or anticipated need for panretinal photocoagulation in the 6 months following randomization * Yag capsulotomy performed within 1 month prior to randomization * External ocular infection including conjunctivitis, significant blepharitis, etc.