Abstract: Objective To evaluate the efficacy of vitrectomy with preoperative intravitreal injection of Bavacizumab (Avastin )for severe proliferative diabetic retinopathy.Methods 42 cases (50 eyes )with severe proliferative diabetis retinopathy treatment by vitrectomy with preoperative intravitreal injection of Bevacizumab (Avastin )were analyzed retrospectively.10～14 days before vitrectomy, intravitreal injection of Bevacizumab (Avastin )1.25mg/0.05ml was performed on all 50 eyes. 7 eyes with traction retinal detachment and severe macular edema were tamponed with silicon iol. 43 eyes with regional tractional retinal detachment and retinal hole were tamponed with gas.Results 50 eyes had little hemorrhage during vitrectomy with intravitreal injection of Bevacizumab (Avastin ). The retinal are all reattatched after the operation. No more severe inflammatory reaction occured after vitrectomy. The intraocular pressure was under controlled.And there were no side effect in oil eyes.Conclusion Intravitreal injection of Bavacizumab (Avastin ) 10～14 days before vitrectomy for severe proliferative diabetic retinopathy can reduce the risk of hemorrhage during the operation and complication after the operation and improve the corrective eyesight after the operation.

Key words: proliferative diabetic retinopathy, Avastin, medicine assistant, vitrectomy