ObjectiveTo investigate the effects of epiretinal membranes (ERMs) on macular hole surgical results and postoperative visual restoration. DesignA subgroup analysis arising from a multicenter, controlled, randomized clinical trial. ParticipantsNinety-one phakic eyes with an idiopathic macular hole that underwent standard vitrectomy for macular hole repair with or without ERM peeling. MethodsPreoperative, intraoperative, and postoperative data of macular status, ERM status, and visual function status were recorded, and their relationships were analyzed. Main outcome measuresVisual acuity and clinical features of macular hole and ERM on baseline examination and scheduled follow-ups. ResultsERM peeling was associated with greater anatomic hole closure success rates (67% of the ERM peeled vs. 35% of nonpeeled, P = 0.03) but not associated with visual improvement in eyes with anatomic hole closure (2.9 lines improvement vs. 3.6 lines improvement, P > 0.5). Macular hole reopening was associated with excessive ERM growth (P = 0.005). Postoperative ERMs were more common in the eyes that underwent cataract surgery after vitrectomy (77% in aphakic and 36% in phakic eyes, P = 0.02). Macular hole edge approximation or hole appearance after initial vitrectomy for hole repair was stable over the average 18-month period in 89% of the eyes; only approximately 10% of the eyes underwent changes in their hole appearance. The hole edge approximation or hole appearance was associated with preoperative hole size and postoperative visual acuity. Preoperative hole size was found to be the major predictor of postoperative visual acuity (P < 0.005). ConclusionsSurgical ERM peeling increases the anatomic hole closure rate. The presence of postoperative ERMs was not associated with postoperative visual acuity; however, excessive ERM growth contributed to hole reopening. Preoperative hole size was the most sensitive predictor for postoperative visual acuity. Surgical intervention during the early stages of macular hole before ERM formation is strongly recommended.