METHODS: Totally 64 patients(75 eyes)with PDR admitted to the hospital between January 2016 and October 2019 were recruited and divided into observation group(32 cases, 38 eyes)and control group(32 cases, 37 eyes)by random number table method. The observation group received vitrectomy and intravitreal injection of Conbercept, while the control group received simple vitrectomy. The best corrected visual acuity(BCVA)was detected before treatment, at 1wk, 1mo, and 3mo after operation. Changes in central macular thickness(CMT)before treatment and at 3mo after operation were determined. Aqueous humor or vitreous humor samples were collected before and after treatment to measure concentrations of vascular endothelial growth factor(VEGF), placental growth factor(PIGF)and basic fibroblast growth factor(bFGF)by enzyme-linked immunosorbent assay. The operation time, intraoperative blood loss and improvement time of symptoms(retinal edema, fundus hemorrhage, exudation)of the 2 groups were statistically analyzed. Incidences of complications in the 2 groups were recorded.

RESULTS: The observation group had better BCVA than the control group at 1wk, 1mo and 3mo after operation(P<0.05), and had smaller CMT than the control group at 3mo after operation(P<0.001). The concentrations of VEGF, PIGF and bFGF in observation group during operation were lower than those in the control group(P<0.001). The operation time, absorption time of retinal edema, fundus hemorrhage and exudation, intraoperative blood loss, and the total incidence of complications in the observation group were shorter and lower than those in the control group(P<0.05).

CONCLUSION: Intravitreal injection of Conbercept before vitrectomy can degrade new blood vessels, and shorten the operation time. It can not only help improve vision and relieve macular edema but also reduce surgical complications and promote postoperative recovery.