AIM: To investigate and analyze serum nitric oxide synthase 4(NOX4)and matrix metalloproteinase(MMP)-2 expressions in patients with diabetes mellitus(DM)complicated with neovascular glaucoma(NVG)and their clinical significance.METHODS: A prospective study was conducted on 161 patients with DM complicated with NVG admitted to Handan City Eye Hospital(The Third Hospital of Handan)from June 2020 to June 2023. Based on whether complications occurred 1 a after trabeculectomy in the study group patients, they were divided into a group with good prognosis(n=90)and a group with poor prognosis(n=71). During the same period, 161 patients with chronic angle-closure glaucoma without iris neovascularization were selected as the control group. ELISA method was applied to detect the expression levels of serum NOX4 and MMP-2. ROC curve was plotted to evaluate the diagnostic value and postoperative complication prediction value of NOX4 and MMP-2 in patients with DM complicated with NVG. Pearson method was applied to analyze the correlation of NOX4 and MMP-2 with vascular endothelial growth factor(VEGF)and interleukin-6(IL-6). Multivariate Logistic regression was applied to analyze the influencing factors of postoperative complications in the study group.RESULTS:The general information of the study group and control group of patients is comparable. Compared with the control group, the expression levels of serum NOX4, MMP-2, VEGF, and IL-6 in the study group were significantly increased(P<0.001). According to Pearson analysis, serum NOX4 and MMP-2 levels significantly positively correlated with VEGF and IL-6 levels, respectively(P<0.001). According to ROC curve, the AUC of NOX4 combined with MMP-2 in the diagnosis of DM complicated with NVG was better than that of individual diagnosis of NOX4(Z=3.341, P<0.05)and MMP-2(Z=2.788, P<0.05). The duration of DM, the proportion of people with intraocular pressure >21 mmHg, and the expression levels of NOX4, MMP-2, VEGF, and IL-6 in the poor prognosis group were all higher than those in the good prognosis group(P<0.001). The duration of DM, intraocular pressure >21 mmHg, the levels of NOX4, MMP-2, VEGF, and IL-6 were all risk factors for poor prognosis in DM patients with NVG(P<0.001). According to ROC curve, the combined prediction of NOX4 and MMP-2 for postoperative complications in patients with DM complicated by NVG was superior to the AUC predicted by NOX4(Z=3.727, P<0.05)and MMP-2(Z=2.219, P<0.05), respectively.CONCLUSION:NOX4 and MMP-2 are upregulated in the serum of patients with DM complicated by NVG. Combined detection of these two markers holds significant clinical value for the early diagnosis and prognosis of patients with DM complicated by NVG.