Discussion
PDR, TRD, Diabetic retinopathy, blindness, ischemia, tamponade
DIABETIC RETINOPATHY, BLINDNESS, ISCHEMIA, COMPLICATION, BLIND, NEOVASCULARIZATION, SCLERA, REGRESSION
Diabetic retinopathy (DR) is one of the leading causes of being legally blind in working-aged people and is responsible for up to 4.8% of blindness worldwide. Although PPV was the standard management for PDR with VH or TRD, they may suffer from postoperative VH. This complication will hinder fundus monitoring and/or additional retinal photocoagulation and delay their visual recovery.The incidence of postoperative VH in PDR had been reported to be around 75% in the 1980s (Vascular endothelial growth factor has been proven to play an important role in the development of neovascularization in DR (These controversies exist because there are numerous differences in the detail of each strategy, such as the time point for the injection of anti-VEGF, the trocar gauge, and the suture of sclera wound. Heterogeneity of baseline characteristics among different studies also made it difficult to compare their results directly. Wang et al. conducted a network meta-analysis including 26 randomized controlled trials (RCTs) and 1,806 patients with PDR to compare preoperative anti-VEGF to the sham group. They found that injection at 6 to 14 days before vitrectomy could significantly reduce the duration of surgery, improve postoperative BCVA, and decrease the incidence of postoperative VH (The ideal timing for pretreatment is controversial. Some authors suggested injecting more than 14 days before vitrectomy to make full use of anti-VEGF agents and induce the complete regression of neovascularization. However, Russo et al. studied the incidence of TRD following preoperative anti-VEGF injection and showed that the incidence of TRD after injection was 2.7% when the interval of injection and vitrectomy was less than 6 days, while it will be increased to 56% when the interval was prolonged to more than 10 days (Postoperative BCVA might be associated with numerous factors, such as the history of TRD, macular edema, macular ischemia, and ellipsoid zone (EZ) band integrity recurrent VH and gas or silicone oil tamponade (To our knowledge, this is the first RCT that compares the incidence of postoperative VH between the preoperative IVA and sham groups for PDR. However, it has the following limitations: (1) failure to compare the influence of different timings of preoperative anti-VEGF injection; (2) having a relatively shorter follow-up period; and (3) the lack of a group with different anti-VEGF agents.In conclusion, this RCT demonstrated that injective IVA at 1 to 5 days before vitrectomy for patients with PDR could reduce the incidence of early and late postoperative VH.