RecruitingProcedureRandomized Trial Comparing Immediate vs. Deferred Surgery for Symptomatic ERMVitrectomy to remove an epiretinal membrane (ERM) is one of the most common procedures performed by retinal surgeons. Patients who present with significant macular changes on optical coherence tomography (OCT) but relatively good vision are often advised to defer surgery until vision declines to 20/40 or worse. However, it is unknown if delaying surgery, which allows the foveal architecture to remain compromised and potentially to deteriorate, results in worse visual acuity outcomes than if surgery is performed earlier. In addition, there is a need to better understand predictors of outcomes when surgery is performed and predictors of progression when surgery is deferred. Finally, one of the most common presenting symptoms from an ERM is distortion or metamorphopsia. There are several objective measures of metamorphopsia but none have ever been employed to evaluate ERMs in a randomized clinical trial (RCT) and their usefulness is unknown. The purposes of this study are to better understand the optimal timing of surgery to produce the best visual result, to better understand predictors of outcomes in those who undergo surgery and predictors of progression in those whose are observed, and to better characterize and evaluate the usefulness of metamorphopsia and reading speed measures.