Abstract: Objective To explore the occasion choice and efficacy of vitrecto my for treatment of proliferative diabetic retinopathy(PDR). Methods 186 patients (242 eyes) with PDR were enrolled in this study. Panretinal photocoagulation (PRP) was performed on 123 eyes and vitrectomy on 119 eyes. All were followed up for 6 to 40 months. Results After vitrectomy, visual acuity was improved in 78.4% eyes of the Ⅳ and ⅤPDR groups and 43.7% of the Ⅵ PDR group. After PRP, visual acuity was improved in 80.8% eyes of theⅣ PDR group and 58.2% of the Ⅴ PDR group. For Ⅴ PDR patients without vitreous hemorrhage, the effective rate of vitrectomy treatment was 78.9% while of PRP it was 58.2%. The main operative complication was iatrogenic retinal holes and the postoperative complications were vitreous rehemorrhage, retinal detachment and neovascular glaucoma. Conclusion A suitable operative occasion is important for patients with PDR to ensure good visual acuity.

Key words: Proliferative diabetic retinopathy, Vitrectomy, Occasion choice