An epiretinal membrane, or "ERM" forms when a few cells lay down on the retinal surface, then multiply and contract. This condition is also known as "macular pucker" and "cellophane retinopathy." In some patients, this condition progresses to visual significance. It can cause wavy vision (metamorphosia) and blurred vision. When a patient is sufficiently bothered by the visual deterioration, a surgery called vitrectomy is performed. This surgery is done in the operating room, and the patient goes home the same day!