Main characteristics of the included studies
| First author | Publication year | Design | Sample size | Group size (patient) | Average age | Details of anti-VEGF agent injection | Details of the surgical procedure | Intraoperative and postoperative evaluating parameters | Follow-up periods (weeks) |
| Case/control | Case/control | ||||||||
| Comyn et al 16 | 2017 | Double-masked RCT | 30 | 15/15 | (57.1±14)/ (48.7±18) | IVR (0.5 mg) 7 days before vitrectomy | 20 G PPV with fibrovascular membranes dissection. Endophotocoagulation, retinopexy and endotamponnade were used when required. | Duration of surgery; the number of back-flush cannula, endodiathermy applications, iatrogenic retinal breaks and silicone oil applications; severity of intraoperative bleeding; surgical complexity score | 12 |
| Postoperative BCVA, recurrent VH, complications | |||||||||
| Yang et al 5 | 2016 | Double-masked RCT | 107 | 54/53 | (48.63±8.24)/ (49.64±8.71) | IVC (0.5 mg) 3 days before vitrectomy | 23 G PPV with fibrovascular membranes dissection. Endophotocoagulation, peripheral retinal cryotherapy and endotamponnade were used when required. | Severity of intraoperative bleeding | 12 |
| Postoperative BCVA, recurrent VH, vitreous clear-up time, complications | |||||||||
| Su et al 14 | 2016 | Double-masked RCT | 36 | 18/18 | NA | IVC (0.5 mg) 7 days before vitrectomy | 23 G PPV with fibrovascular membranes dissection. Endophotocoagulation and endotamponnade were used when required. | Duration of surgery; the number of endodiathermy applications, iatrogenic retinal breaks, relaxing retinotomy and silicone oil applications; severity of intraoperative bleeding; erythrocyte count; surgical complexity score | 12 |
| Postoperative BCVA, recurrent VH, complications | |||||||||
| Sohn et al 22 | 2012 | Double-masked RCT | 19 | 10/9 | NA | IVB (0.5 mg) 3–7 days before vitrectomy | 20 G PPV with fibrovascular membranes dissection. Endophotocoagulation, endotamponnade, scleral buckling and lensectomy were used when required. | BCVA, intraoperative bleeding and silicone oil applications; postoperative recurrent VH | 12 |
| VEGF and CTGF levels in the vitreous and aqueous | |||||||||
| Han et al 23 | 2012 | RCT | 24 | 12/12 | (50.33±7.6)/ (53.25±5.14) | IVB (1.25 mg) 6 days before vitrectomy | PPV with fibrovascular membranes dissection. The epiretinal membranes were collected | The levels of vascular endothelial cells, VEGF and HIF-1α | NA |
| Farahvash et al 17 | 2011 | Double-masked RCT | 35 | 18/17 | (58.3±24.1)/ (58.7±34.14) | IVB (1.25 mg) 7 days before vitrectomy | 20 G PPV. Endophotocoagulation and endotamponnade were used when required. | The number of endodiathermy applications, iatrogenic retinal breaks and silicone oil applications; severity of intraoperative bleeding; surgical complexity score | 12 |
| Postoperative BCVA, recurrent VH, complications | |||||||||
| Ahn et al 18 | 2011 | RCT | 70 | 36/34 | (51.0±9.5)/ (55.0±11.4) | IVB (1.25 mg) 1–14 days before vitrectomy | 23 G PPV with fibrovascular membranes dissection. Endodiathermy and endolaser photocoagulation were used when required. | Postoperative BCVA, recurrent VH, vitreous clear-up time and complications | 24 |
| Hernandez-Da15 | 2010 | RCT | 40 | 20/20 | (55.7±9.9)/ (55.7±7.4) | IVB (1.25 mg) 2 days before vitrectomy | 23 G PPV with fibrovascular membranes dissection. Endophotocoagulation and endotamponnade were used when required. | Duration of surgery; severity of intraoperative bleeding | 24 |
| Postoperative BCVA, recurrent VH, complications | |||||||||
| di Lauro et al 24 | 2010 | RCT | 72 | 24/24/24 | NA | IVB (1.25 mg) 7 or 20 days before vitrectomy | 20 G PPV with fibrovascular membranes dissection. Endophotocoagulation and endotamponnade were used when required. | Duration of surgery; the number of endodiathermy applications, iatrogenic retinal breaks, relaxing retinotomy and silicone oil applications; severity of intraoperative bleeding | 24 |
| Postoperative BCVA, recurrent VH, complications | |||||||||
| Modarres et al 25 | 2009 | Surgeon-masked RCT | 40 | 22/18 | (55.8±11.3)/ (53.2±11.7) | IVB (2.5 mg) 3–5 days before vitrectomy | 20 G PPV with fibrovascular membranes dissection. Endophotocoagulation, retinotomy and endotamponnade were used when required. | Duration of surgery; the number of endodiathermy applications, iatrogenic retinal breaks, relaxing retinotomy and silicone oil applications; severity of intraoperative bleeding; surgical complexity score | 12 |
| Postoperative BCVA, recurrent VH, complications | |||||||||
| Ahmadieh et al 26 | 2009 | Double-masked RCT | 68 | 35/33 | (53.69±11.7)/ (56.70±10.4) | IVB (1.25 mg) 7 days before vitrectomy | PPV with endophotocoagulation and endocautery when required. | The number of iatrogenic retinal breaks and intraoperative bleeding | 4 |
| Postoperative BCVA, recurrent VH, complications | |||||||||
| Da and Lucena et al 27 | 2009 | Double-masked RCT | 20 | 10/10 | NA | IVB (1.5 mg) 14 days before vitrectomy | 23 G PPV with fibrovascular membranes dissection. Endophotocoagulation and endotamponnade were used when required. | Erythrocyte count | – |
| Rizzo et al 28 | 2008 | RCT | 22 | 11/11 | NA | IVB (1.25 mg) 5–7 days before vitrectomy | 20 G PPV with fibrovascular membranes dissection. Endophotocoagulation and endotamponnade were used when required. | Preoperative complexity score, duration of surgery; the number of too exchanges, endodiathermy applications, iatrogenic retinal breaks; severity of intraoperative bleeding | 24 |
| Postoperative BCVA and complications | |||||||||
| El-Batarny4 | 2008 | RCT | 30 | 15/15 | (44±11)/ (46±12) | IVB (1.25 mg) 5–7 days before vitrectomy | 23 G PPV with fibrovascular membranes dissection. Endophotocoagulation, peripheral retinal cryotherapy and endotamponnade were used when required. | Duration of surgery; the number of endodiathermy applications, iatrogenic retinal breaks, relaxing retinotomy and silicone oil applications; severity of intraoperative bleeding; | 24 |
| Postoperative BCVA and complications |
BCVA, best-corrected visual acuity; CTGF, connective tissue growth factor; HIF-1α, hypoxia-inducible factor-1α; IVB, intravitreal injection of bevacizumab; IVC, intravitreal injection of conbercept; IVR, intravitreal injection of ranibizumab; NA, not available; PPV, pars plana vitrectomy; RCT, randomised controlled trials; VEGF, vascular endothelial growth factor; VH, vitreous haemorrhage.