To identify characteristics measured by optical coherence tomography (OCT) that are correlated with visual outcome after epiretinal membrane (ERM) removal by pars plana vitrectomy (PPV). Interventional, prospective, randomized case series. One hundred and one eyes of 101 patients with idiopathic ERM underwent PPV for ERM removal. Ophthalmic evaluations included best-corrected visual acuity (BCVA) and Stratus OCT preoperatively at 3 and 6 months postoperatively. Relations between three OCT features including integrity of junction between inner and outer segments of photoreceptors (IS/OS junction), macular thickness, foveal contour and the three visual acuity parameters such as preoperative BCVAs, postoperative BCVAs, and the differences between preoperative and postoperative BCVAs (BCVA differences) were evaluated with respect to time. Eyes with disruption of IS/OS junction had significantly lower postoperative BCVA and BCVA differences than those without disruption (P 0.25; P .05, respectively). Photoreceptor disruption detected by OCT was found to be a predictor of poor visual outcome in eyes with idiopathic ERM, and it was found that this disruption may be irreversible. Thus, early membrane removals may beneficially prevent further progression of photoreceptor damage in ERM patients with photoreceptor disruption.