A Safety and Efficacy Trial of a Treat and Extend Protocol Using Ranibizumab With and Without Laser Photocoagulation for Diabetic 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 of age Patient related considerations * 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 * Although no birth control method is 100% effective, the following are considered effective means of contraception: surgical sterilization, use of oral contraceptives, barrier contraception using either a condom or diaphragm with spermicidal gel, an intrauterine device, or contraceptive hormone implant or patch. A patient's primary care physician, obstetrician, or gynecologist should be consulted regarding an appropriate form of birth control. * Ability and willingness to return for all scheduled visits and assessments Disease related considerations * The presence of center-involving diabetic macular edema on clinical exam and SDOCT * Best corrected visual acuity in the study eye, using ETDRS testing, between 20/25 and 20/320 (Snellen equivalent), inclusive. * Clear ocular media and adequate pupillary dilation to permit good quality fundus imaging. Exclusion Criteria: * General Exclusion Criteria * Pregnancy (positive urine 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 (Intrauterine Device) , 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 Ocular Exclusion Criteria Prior Ocular Treatment * History of active proliferative diabetic retinopathy in the study eye on clinical exam * History of vitrectomy surgery, submacular surgery, or other intraocular surgical intervention for diabetic macular edema in the study eye * Any previous intravitreal drug delivery (e.g., intravitreal corticosteroid injection, anti-VEGF drugs including ranibizumab, or device implantation) in the study eye within 90 days of the screening visit. * History of prior laser macular photocoagulation more than 90 days prior to screening will be eligible for study inclusion. However, if the investigator does not feel that additional laser photocoagulation can be safely performed or would benefit the patient, then the eye in consideration will be excluded. * Evidence of vitreomacular interface abnormality or epiretinal membranes which may be responsible for macular edema Concurrent Ocular Conditions • Any concurrent intraocular condition in the study eye (e.g., cataract or macular degeneration) that, in the opinion of the investigator, could either: Require medical or surgical intervention during the 24-month study period to prevent or treat visual loss that might result from that condition; or if allowed to progress untreated, could likely contribute to loss of at least 2 Snellen equivalent lines of BCVA (Best Corrected Visual Acuity) over the 24-month study period. * Active intraocular inflammation (grade trace or above) in the study eye * Current vitreous hemorrhage in the study eye * History of rhegmatogenous retinal detachment or macular hole (Stage 3 or 4) in the study eye * Active infectious conjunctivitis, keratitis, scleritis, or endophthalmitis in either eye * Aphakia or absence of the posterior capsule in the study eye * Intraocular surgery (including cataract surgery) in the study eye within 3 months preceding Day 0 * Uncontrolled glaucoma in the study eye (defined as IOP (Intraocular Pressure) ≥ 30 mmHg despite treatment with anti-glaucoma medication) * History of glaucoma-filtering surgery in the study eye * History of corneal transplant in the study eye * History of pars plana vitrectomy Concurrent Systemic Conditions * Any history of use of systemic anti-VEGF (Vascular Endothelial Growth Factor) agents * Uncontrolled blood pressure (defined as systolic \> 180 mmHg and/or diastolic \> 110 mmHg while patient is sitting) If a patient's initial reading exceeds these values, a second reading may be taken 30 or more minutes later. If the patient's blood pressure needs to be controlled by antihypertensive medication, the patient can become eligible if medication is taken continuously for at least 30 days prior to Day 0. * Atrial fibrillation not managed by patient's primary care physician or cardiologist within 3 months of screening visit * Women of childbearing potential not using adequate contraception (as defined in the inclusion criteria). A woman is considered not to be of childbearing potential if she is postmenopausal, defined by amenorrhea for at least 1 year in a woman \> 45 years old; or has undergone hysterectomy and/or bilateral oophorectomy. * History of stroke within the last 3 months of screening visit * History of other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use an investigational drug or that might affect interpretation of the results of the study or renders the patient at high risk for treatment complications * Current treatment for active systemic infection * Active malignancy * History of allergy to fluorescein, not amenable to treatment * Inability to obtain fundus photographs or fluorescein angiograms of sufficient quality to be analyzed and graded by the reading center * Inability to comply with study or follow-up procedures * Previous participation in any studies of investigational drugs within 1 month preceding Day 0 (excluding vitamins and minerals)