Prompt Panretinal Photocoagulation Versus Ranibizumab+Deferred Panretinal Photocoagulation for Proliferative Diabetic Retinopathy

Inclusion Criteria: Age >= 18 years -Individuals < 18 years old are not being included because proliferativediabetic retinopathy (PDR) is so rare in this age group that the diagnosis of PDR may bequestionable. Diagnosis of diabetes mellitus (type 1 or type 2) Any one of the following will be considered to be sufficient evidence that diabetes ispresent:

• Current regular use of insulin for the treatment of diabetes
• Current regular use of oral anti-hyperglycemia agents for the treatment of diabetes
• Documented diabetes by American Diabetes Association (ADA) and/or World HealthOrganization (WHO) criteria (see Procedures Manual for definitions) Able and willingto provide informed consent. Meets at least all of the following ocular criteria criteria:
• Presence of PDR which the investigator intends to manage with PRP alone but for whichPRP can be deferred for at least 4 weeks in the setting of intravitreal ranibizumab,in the investigator's judgment.
• Best corrected Electronic-Early Treatment Diabetic Retinopathy Study (E-ETDRS) visualacuity letter score > 24 (approximate Snellen equivalent 20/320) on the day ofrandomization.
• Media clarity, pupillary dilation, and study participant cooperation sufficient toadminister PRP and obtain adequate fundus photographs and optical coherence tomography (OCT).
• Investigator must verify accuracy of OCT scan by ensuring it is centered and ofadequate quality

Exclusion Criteria: Significant renal disease, defined as a history of chronic renal failure requiring dialysisor kidney transplant. A condition that, in the opinion of the investigator, would preclude participation in thestudy (e.g., unstable medical status including blood pressure, cardiovascular disease, andglycemic control).

• Individuals in poor glycemic control who, within the last 4 months, initiatedintensive insulin treatment (a pump or multiple daily injections) or plan to do so inthe next 4 months should not be enrolled. Participation in an investigational trial within 30 days of randomization that involvedtreatment with any drug that has not received regulatory approval for the indication beingstudied.
• Study participants cannot receive another investigational drug while participating inthe study. Known allergy to any component of the study drug. Blood pressure > 180/110 (systolic above 180 or diastolic above 110).
• If blood pressure is brought below 180/110 by anti-hypertensive treatment, individualcan become eligible. Myocardial infarction, other acute cardiac event requiring hospitalization, stroke,transient ischemic attack, or treatment for acute congestive heart failure within 4 monthsprior to randomization. Systemic anti-VEGF or pro-VEGF treatment within 4 months prior to randomization.
• These drugs should not be used during the study. For women of child-bearing potential: pregnant or lactating or intending to become pregnantwithin the next 3 years.
• Women who are potential study participants should be questioned about the potentialfor pregnancy. Investigator judgment is used to determine when a pregnancy test isneeded. Individual is expecting to move out of the area of the clinical center to an area notcovered by another Diabetic Retinopathy Clinical Research Network (DRCR.net) certifiedclinical center during the 3 years of the study. Individual has any of the following ocular characteristics:
• History of prior panretinal photocoagulation (prior PRP is defined as ≥ 100 burnsoutside of the posterior pole)
• Tractional retinal detachment involving the macula. -- A tractional retinal detachment is not an exclusion if it is outside of theposterior pole (not threatening the macula) and in the investigator's judgment, is nota contraindication to intravitreal ranibizumab treatment and also does not precludedeferring PRP for at least 4 weeks in the setting of intravitreal ranibizumab
• Exam evidence of neovascularization of the angle (neovascularization of the iris aloneis not an exclusion if it does not preclude deferring PRP for at least 4 weeks in theinvestigator's judgment).
• If macular edema is present, it is considered to be primarily due to a cause otherthan diabetic macular edema. -- An eye should not be considered eligible if:
• macular edema is present that is considered to be related to ocular surgery suchas cataract extraction or
• clinical exam and/or OCT suggest that vitreoretinal interface abnormalitiesdisease (e.g., a taut posterior hyaloid or epiretinal membrane) is the primarycause of any macular edema.
• An ocular condition is present (other than diabetic retinopathy) that, in the opinionof the investigator, might alter visual acuity during the course of the study (e.g.,retinal vein or artery occlusion, uveitis or other ocular inflammatory disease,neovascular glaucoma, etc.). -- A vitreous or preretinal hemorrhage is not an exclusion if it is out of the visualaxis and in the investigator's judgment is not having any affect on visual acuity.
• Substantial cataract that, in the opinion of the investigator, is likely to bedecreasing visual acuity by 3 lines or more (i.e., cataract would be reducing acuityto 20/40 or worse if eye were otherwise normal).
• History of intravitreal anti-VEGF treatment at any time in the past 2 months.
• History of corticosteroid treatment (intravitreal or peribulbar) at any time in thepast 4 months. --If the investigator believes that there may still be a substantial effect 4 monthsafter prior treatment (e.g., dose of intravitreal triamcinolone higher than 4 mg), theeye should not be included.
• History of major ocular surgery (including vitrectomy, cataract extraction, scleralbuckle, any intraocular surgery, etc.) within prior 4 months or anticipated within thenext 6 months following randomization.
• History of (yttrium-aluminum-garnet) YAG capsulotomy performed within 2 months priorto randomization.
• Aphakia.
• Uncontrolled glaucoma (in investigator's judgment).
• Exam evidence of severe external ocular infection, including conjunctivitis,chalazion, or substantial blepharitis