Day Regimes of CONbercept on CytokinEs of PDR Patients Undergoing Vitrectomy - Trial (CONCEPT)

Inclusion Criteria: * 18 years or older * Type 1 or 2 diabetes * PDR patients requiring surgical intervention for complications of vitreous hemorrhage or traction retinal detachment and pre-operative IVC treatment. * women postmenopausal for 12 months before the study, surgically sterile, or not pregnant and on effective contraception. Exclusion Criteria: * previous retinal vein occlusion. * any intraocular surgery within the previous 12 months. * myopia of \> or = to 8 diopters. * active ocular or periocular infection * treatment with an investigational agent for any condition 60 days prior to enrollment. * evidence of severe cardiac disease. * clinically significant peripheral vascular disease (previous surgery, amputation, or symptoms of claudication) * uncontrolled hypertension (treated systolic blood pressure \> 155 mmHg or diastolic blood pressure \> 95 mmHg) * stroke within the preceding 12 months.