Idiopathic epiretinal membrane (ERM) is characterized by the growth of fibrocellular tissue on the internal limiting membrane (ILM). An ERM can range from a subtle cellophane-like film that does not cause any visual disturbance to a significant, multilayered, contractile membrane with folds in the underlying and adjacent retina, causing metamorphopsia and a decline in visual acuity. Although the exact pathogenesis of ERM formation is unclear, it is known to be associated with posterior vitreous detachment 1 leading to hypertrophy of glial (Muller) cell processes and the accumulation of extracellular matrix components on the ILM. The ILM is the basement membrane of the Muller cells. 2,3 ' ERM Surgery
Pars Plana VitrectomyAlthough there are rare cases in which an ERM spontanously separates from the retina and induces regression of the macular distortion, 4,5 in the great majority of cases it remains stable or progresses slowly. Progression of an ERM often results in underlying retinal changes with thickening and/or folds that can lead to a decline in visual acuity. Standard pars plana vitrectomy to remove the vitreous gel and ERM has traditionally been the standard of therapy for visually significant ERM and usually results in significant regression of the retinal thickening and/or folds. However, reports show that the