An Epiretinal Membrane (ERM) or macular pucker is caused by an abnormal membrane that grows over the macular surface. In some individuals, this membrane contracts, which results in wrinkling of the retina. This contraction may mechanically irritate the retina and cause retinal swelling. Approximately 15-20% of epiretinal membranes progressively worsen.

Symptoms
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.

Diagnosis
An Epiretinal Membrane has a characteristic clinical appearance, and the diagnosis is made by the physician during a dilated exam. In some cases Fluorescein Angiography may be used to determine if swelling is present and to rule out other retinal diseases. Optical Coherence Tomography (OCT) which provides a scan, or slice of the retina can be very useful in identifying irregularities along the retinal surface.

Treatment
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 vitrectomy surgery, the vitreous gel is removed. Following this, the epiretinal membrane is peeled from the surface of the retina and removed using microscopic forceps. Removing the vitreous is not harmful to the function of the eye. Vitrectomy surgery is an outpatient procedure usually performed under local anesthesia. Significant improvement in vision occurs in most patients after epiretinal membrane removal.