Fundoscopy image of the retina of the left eye of a patient with temporal epiretinal membranes. The retina is the light-sensitive layer at the back of the eye. An epiretinal membrane is a layer of scar tissue that grows across the macula (centre) and distorts the retinal tissue as it contracts and thickens. This impairs sight by distorting the central area of vision, but does not cause total blindness. Treatment is by removing the membrane in a procedure known as a vitrectomy. Choroidal folds (thin dark horizontal lines) can also be seen.