AIM: To investigate the risk factors associated with neovascular glaucoma(NVG)after pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR).

METHODS: The PDR patients who received 23G PPV treatment at Shenyang He Eye Specialist Hospital from October 2015 to September 2020 and were followed up for at least 12mo with complete data were retrospectively collected. The patients were divided into two groups according to the occurrence of NVG during follow-up. The preoperative and intraoperative variables between two groups were compared. The cumulative hazard ratio for NVG was evaluated.

RESULTS: A total of 151 PDR patients(169 eyes)with a mean follow-up of 18.07±12.55(1～79)mo were included, of which 30(17.8%)eyes developed NVG, the mean time of occurrence was 6.27±4.01(1～17)mo, and 50%(15 eyes)of NVG occurred within 5mo after vitrectomy. The cumulative hazard ratios of NVG at postoperative 3, 6 and 12mo were 4.8%, 12.6% and 18.1%, respectively. Multivariate logistic regression analysis showed that preoperative best corrected visual acuity(OR=3.077, 95%CI: 1.203～7.869, P=0.019), preoperative iris rubeosis(OR=7.897, 95%CI: 1.313～47.498, P=0.024), and contralateral NVG(OR=22.108, 95%CI: 1.562～312.861, P=0.022)were risk factors with the occurrence of NVG, while the number of intraoperative retinal laser photocoagulation(OR=0.772, 95%CI: 0.666～0.893, P=0.001)was the protective factor with the occurrence of NVG.

CONCLUSIONS: The incidence of NVG in PDR eyes after PPV was 17.8%, of which 50% occurred within 5mo after surgery. PDR eyes with poor baseline visual acuity, iris rubeosis, and contralateral NVG are prone to postoperative NVG, and sufficient intraoperative retinal laser photocoagulation has a certain protective effect. PDR eyes after PPV should be closely followed up for 1a.