E piretinal membrane (ERM) is a common retinal disease characterized by cellular proliferation and metaplasia that lead to the formation of a pathological fbrocellular membrane immediately superjacent to the inner retinal surface (Figs. 1A and 1B). Te terms epimacular membrane, macular pucker, cellophane maculopathy, and preretinal macular fbrosis have been used to describe this condition [1-7]. Of late, technology related to ERM surgery, includ- ing imaging analyses and surgical devices, has made rapid progress. In this review, we provide an overview of and recent insights into the surgical management of ERM. Epidemiology and Pathogenesis of ERM Te vast majority of ERM cases are considered idio- pathic and unassociated with other systemic or ocular diseases. Tey are found most frequently afer 50 years of age, and several large clinical studies have reported a clinical prevalence of 7% to 11.8% [8 , 9]. Most ERMs are asymptomatic, with many being extrafoveal in loca- tion. Tere appears to be no signifcant gender predi- lection, and ERM is bilateral in 20-30% of cases. Posterior vitreous detachment (PVD) is present in up to 90% of clinically signifcant ERMs, with spontaneous posterior hyaloid separation believed to be the causative factor. Te Blue Mountains Eye Study reported second eye involvement over a 5-year period in 13.5% of patients [10]. Acta Med. Okayama, 2021 Vol. 75, No. 4, pp. 403-413 CopyrightⒸ 2021 by Okayama University Medical School. http: // escholarship.lib.okayama- u.ac.jp / amo/ Review Surgical Treatment of Epiretinal Membrane Ryo Matoba, and Yuki Morizane ＊ Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan Epiretinal membrane (ERM) is a common retinal disease characterized by cellular proliferation and metaplasia that lead to the formation of a pathological fbrocellular membrane immediately superjacent to the inner retinal surface. Te vast majority of ERMs are considered idiopathic. However, ERM formation can result from vari- ous primary intraocular diseases, including retinal breaks and detachment, retinal vascular diseases, and vit- reoretinal infammatory conditions. Although ERMs are generally asymptomatic or cause mild metamorphop- sia and/or a modest decrease in visual acuity, some can cause severe macular distortion and macular edema, resulting in signifcantly impaired function. Surgical removal of ERM is the only treatment, and improvements in vitrectomy systems have enabled less invasive treatment. However, there are currently no standardized crite- ria for ERM surgery, and the indications for surgery are determined from the patient’s subjective symptoms. Another problem with ERM surgery is that not all patients show satisfactory postoperative recovery of visual function. Tus, further research is needed to determine the criteria for ERM surgery and methods to improve the postoperative prognosis. Key words: epiretinal membrane, vitrectomy, optical coherence tomography, internal limiting membrane, lamel- lar macular hole Received March 3, 2021 ; accepted April 26, 2021. ＊ Corresponding author. Phone : +81-86-235-7297; Fax : +81-86-222-5059 E-mail : moriza-y@okayama-u.ac.jp (Y. Morizane) Confict of Interest Disclosures: No potential confict of interest relevant to this article was reported.