Abstract:

 Objective To investigate the effect of vitrectomy combined with different dosing regimen of ranibizumab on the central foveal thickness (CFT), visual recovery, serum cystatin C (CysC) and vascular endothelial growth factor (VEGF) levels in patients with proliferative diabetic retinopathy (PDR). Design Prospective case series. Participants Ninety-six patients (96 eyes) with PDR diagnosed and treated in the hospital from January 2016 to December 2017 were enrolled. Methods All patients underwent elective vitrectomy, and they were divided into 3 groups using the random number table method, 32 cases in each group. Group A was treated with intravitreal injection of ranibizumab before surgery. Group B was treated with intravitreal injection of ranibizumab during surgery and group C was not injected any drugs. The best-corrected visual acuity (BCVA) was measured before and after surgery. The optical coherence tomography (OCT) was used to measure CFT and serum levels of CysC and VEGF were determined by enzyme linked immunosorbent assay (ELISA).  Main Outcome Measures The BCVA before and after surgery, improvement of visual acuity, CFT, serum CysC and VEGF levels. Results The CFT, serum CysC and VEGF levels in the 3 groups were significantly decreased at 3 months after surgery (all P<0.05). The improvement of visual acuity in group A and group B at 3 months after surgery was significantly better than that in group C (both P<0.05). The CFT, serum CysC and VEGF levels in group A and group B at 3 months after surgery were significantly lower than those in group C (all P<0.05), but there was no significant difference between group A and group B (all P>0.05). The incidence rates of massive hemorrhage and iatrogenic retinal hole in group A (3.1% and 6.3%) and group B (3.1% and 3.1%) during surgery were significantly lower than those in group C (21.9% and 25.0%) (both P<0.05). The incidence of vitreous re-hemorrhage in group B was significantly lower than that in group C (3.1% vs 28.1%) (P<0.05), and there was no significant difference, compared with that in group A (12.5%) (P>0.05). Conclusion The injection of ranibizumab before or during surgery combined with vitrectomy can significantly reduce the CFT, improve the visual acuity of patients with PDR, significantly decrease serum CysC and VEGF levels and complications. In addition, the effect of intravitreal injection of ranibizumab during surgery is slightly better than injection before surgery. （Ophthalmol CHN， 2019, 28： 115-119）

Key words: proliferative diabetic retinopathy, vitrectomy, ranibizumab, vascular endothelial growth factor