Risk factors associated with neovascular glaucoma after vitrectomy in eyes with proliferative diabetic retinopathy

Abstract

Objective To investigate the risk factors associated with neovascular glaucoma (NVG) after pars plana vitrectomy (PPV) in eyes with proliferative diabetic retinopathy (PDR). Methods Retrospective study. One hundred and thirty-seven patients (137 eyes) with PDR who underwent PPV were recruited. There were 85 males and 52 females. The average age was (60.1±8.8) years old. The duration of diabetes was (10.2±3.6) years. There were 49 patients with ipsilateral carotid artery stenosis. Fifty-three eyes underwent intravitreal ranibizumab or conbercept injection before PPV. All eyes were treated with 23G standard three-port PPV. The average follow-up time after PPV was 11.5 months. Fundus fluorescein angiography (FFA) was conducted in postoperative 4-6 weeks to observe non-perfused retinal areas. Risk factors, such as ipsilateral carotid artery stenosis, the presence of non-perfusion in retina after PPV and the application of anti-vascular endothelial growth factor (VEGF) drugs before PPV, were identified by logistic regression. Results Twenty of 137 patients (14.6%) developed postoperative NVG after PPV. Ipsilateral carotid artery stenosis [odds ratio (OR) = 5.048, 95% confidence interval (CI) 2.057-12.389, P=0.000] and the presence of non-perfusion in retina after PPV (OR =4.274, 95%CI 1.426-12.809, P=0.009) were significant risk factors for postoperative NVG, while the application of anti-VEGF drugs was not (OR=1.426, 95%CI 0.463-4.395, P=0.536). But the time from PPV to the onset of NVG varies significantly between the two groups of injection of anti-VEGF drugs or not (t=-4.370, P=0.000). Conclusions Risk factors associated with NVG after PPV in eyes with PDR included ipsilateral carotid artery stenosis and the presence of non-perfusion in retina after PPV. The application of anti-VEGF drugs before PPV can delay the onset of NVG in PDR eyes after vitrectomy. Key words: Glaucoma, neovascular/etiology; Diabetic retinopathy/surgery; Vitrectomy; Root cause analysis