The enrolled eyes were randomly assigned according to the Central Randomization System with a ratio of 1∶1 to IVA group and control group. Patients in IVA group received an IVA (0.5 mg/0.05 ml) injection before surgery (1 to 5 days before surgery); patients in control group did not receive IVA injection before vitrectomy. The preoperative IVA injection was performed following a standard protocol. All patients underwent 25-gauge transconjunctival sutureless vitrectomy using the 25-gauge trocar and cannula system under local or anesthesia. Procedures such as fibrovascular membrane dissection, endodiathermy, or endolaser photocoagulation were performed with 25-gauge instruments as required. Intraoperative bleeding was controlled by either endodiathermy or increasing the irrigation pressure. Patients were examined 1 week, 1 month, 2 months, and 3 months after surgery if there were no postoperative events. If postoperative complications, including VH, occurred, patients were instructed to visit the clinic regardless of the visit schedule. At each visit, any events involving the study eye between the visit schedules were recorded accordingly. At each postoperative visit, slit-lamp biomicroscope, indirect ophthalmoscopy, and fundus photographs were performed. The primary outcome of this study was incidence of VH after vitrectomy.~Postoperative VH was defined as a new episode of VH of grade 1 or above occurring later than 3 days after primary surgery and was evaluated according to the Diabetic Retinopathy Vitrectomy Study grading system. Incidence of VH at week 1, month 1, month 2 and month 3 were recorded. In the case of gas-injected eye, complications were assessed in the region without the gas bubble.~Preoperative, intraoperative, and postoperative data were collected for each patient. Preoperative data included age; sex; duration and status of diabetes mellitus (HbA1C); other systemic diseases such as hypertension and renal function (serum creatinine); and ophthalmic parameters including best-corrected visual acuity (BCVA), intraocular pressure (IOP), lens status, previous pan-retinal photocoagulation (PRP), and indication for surgery. Intraoperative data included phacoemulsification and intraocular lens (IOL) procedures, SF6 or air tamponade, and the presence of fibrovascular proliferation and tractional retinal detachment. Postoperative data included BCVA at each visit and number of episodes of complications.
Aflibercept, a recombinant fusion antibody that binds to all subtypes of VEGF and PlGF, has been shown to induce effective regression of retinal neovascularization secondary to PDR but there had been lack of a well-structured prospective study about adjunctive use of intravitreal injection of Aflibercept (IVA) to reduce postoperative VH in PPV for PDR. In this study, we aim to assess the effect of preoperative IVA on the incidence of postoperative VH after PPV for PDR.