Objectives. The aim of this study is to evaluate longitudinal RNFL thickness changes in patients with open-angle glaucoma (OAG) who underwent pars plana vitrectomy (PPV) with epiretinal membrane (ERM) and ILM removal using OCT RTVue XR 100 Avanti. Methods. Retrospective analysis of OCT scans of 40 patients who underwent PPV or combined phacovitrectomy with ILM peeling for the idiopathic ERM has been carried out. The patients were divided into two groups for the study: patients with the ERM and OAG and those with ERM without glaucoma. A trend analysis of the RNFL thickness changes in 1 month and 3, 6, and 12 months was created. Results. At 1 month after surgery, the RNFL thickness increased significantly in the temporalis quadrant from 89.9 μm to 105.7 μm in patients with OAG. Comparison between group with OAG and group without glaucoma showed that the RNFLT in the temporalis quadrant decreased significantly 6 months after the surgery. Conclusion. Postoperative changes in RNFL thickness appeared to be transient, and there was temporal retardation of the retinal nerve fibers without affecting visual acuity in both groups.