Dosing Study of Ranibizumab for Diabetic Retinal and Macular Edema

Inclusion Criteria: * Ability to provide written informed consent and comply with study assessments for the full duration of the study * Age \> 18 years * Patient related considerations * Phakic or pseudophakic patients with a known history of diabetes will be eligible. * Women of reproductive age will be required to take a urine pregnancy test prior to administration of the study drug. * Disease related considerations: * Patients will have met standard, accepted diagnostic criteria for diabetes and will be currently treated with at least one systemic antihyperglycemic or insulin medication. * Patients will have a BCVA ETDRS Snellen-equivalent less than or equal to 20/40 * Central foveal thickness on SD-OCT of \>300um Exclusion Criteria: * Pregnancy (positive pregnancy test) or lactation Premenopausal women not using adequate contraception. The following are considered effective means of contraception: surgical sterilization or use of oral contraceptives, barrier contraception with either a condom or diaphragm in conjunction with spermicidal gel, an IUD, or contraceptive hormone implant or patch. * 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 * Foveal ischemia on IVFA * Intraocular surgery less than 6 months ago * Epiretinal membrane of clinical significance * Prior vitrectomy * Uncontrolled glaucoma * Macular or peripheral laser within 90 Days from Day 0 injection * Intravitreal steroid injection within 90 days from Day 0 injection * Intravitreal or systemic anti-VEGF within 30 days from Day 0 injection