An Epiretinal Membrane (ERM) or macular pucker is caused by a fibrous membrane that grows over the macular surface. In some individuals, the membrane contracts, resulting in a wrinkling of the retina. This contraction may mechanically irritate the retina and cause retinal swelling. Approximately 20% of epiretinal membranes progressively worsen.
An ERM may cause symptoms ranging from minor distortion of images to severe loss of vision. Visual acuity can range from 20/20 to 20/200.
An Epiretinal Membrane has a characteristic clinical appearance, and the diagnosis is made by the physician during a dilated exam. Optical Coherence Tomography (OCT) provides a scan or slice of the retina which is useful in identifying epiretinal membranes. In some cases, Fluorescein Angiography may be used to rule out other retinal diseases.
When vision declines, vitrectomy surgery to remove the epiretinal membrane may be recommended. Eye drops, medications, or glasses will not correct the loss of vision. During surgery, the vitreous gel is removed. Following this, the epiretinal membrane is peeled from the surface of the retina and removed with microscopic forceps. Removing the vitreous is not harmful to the function of the eye. The surgery is an outpatient procedure, usually performed under local anesthesia. Significant improvement in vision occurs in most patients following epiretinal membrane removal.