We report about our clinical experience when comparing the preoperative retinometer values with the postoperative visual acuity after microsurgical excision of epiretinal membranes (ERM).Pars plana vitrectomy with membrane peeling was performed in 56 eyes of 53 patients. Preoperatively, we obtained the distant and near visual acuity and the retinometer value. Postoperatively, we compared the preoperative retinometer value to the best postoperative visual acuity.The preoperative retinometer value was in 39 eyes (70 %) equal to the best postoperative distant visual acuity (+/- 1 line) and in 34 eyes (61 %) equal to the best near visual acuity (+/- 1 line). A difference of + 2 or - 2 lines or more from the retinometer value was found in 17 eyes (30 %) for the best postoperative distant visual acuity and in 22 eyes (39 %) for the best near visual acuity. 49 eyes (87.5 %) had a better visual acuity after pars plana vitrectomy, 6 eyes (10.7 %) had equal visual acuities and one eye (1,8 %) was worse than the preoperative visual acuity. The average improvement of vision after the operation was + 2.5 lines for the distant and + 2.4 lines for the near visual acuity.The preoperative retinometer examination is a precise method for obtaining the visual acuity of patients selected for pars plana vitrectomy with membrane peeling. Uncertain results can be achieved in eyes with very opaque ERM and ERM with macular edema.