Epiretinal membrane (ERM), or macular pucker, is a fibrous membrane that grows over the macular surface. In some individuals, the membrane contracts, resulting in a wrinkling of the retina. This contraction will mechanically irritate the retina and may cause retinal swelling. Epiretinal membrane is more common in patients with posterior vitreous detachment (PVD), retinal tears, previous retinal detachments, uveitis, vein occlusions, and diabetic retinopathy. Approximately 20% of epiretinal membranes progressively worsen with time.
Epiretinal membrane may cause symptoms ranging from minor distortion of images to severe loss of vision. Visual acuity can range from 20/20 to 20/200 or worse. In severe cases, patients often describe difficulty with reading, driving, and using their eyes together.
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 an image of the retina which is useful in identifying epiretinal membranes. OCT demonstrates folding of the inner retina from traction. Lamellar holes and edema are readily detected. Worsening of disease can be monitored with serial OCT scans. In some cases, fluorescein angiography may be used to help assess the severity of the disease and 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 and helps by eliminating floaters. The surgery is an outpatient procedure, usually performed under local anesthesia. Significant improvement in vision occurs in over 80% of patients following epiretinal membrane removal.
Severe complications following vitrectomy for epiretinal membrane are uncommon. They include retinal tear or detachment, alteration of eye pressure, or infection.
Cataract progression commonly occurs following removal of the vitreous, as performed during vitrectomy.
From the Expert…
Epiretinal membranes are a very common ocular disease, affecting as many as 30 million Americans. The majority of patients experience minimal visual disturbance. In about 20% of patients, the pucker worsens and causes progressive vision loss.
Surgery is recommended when the condition interferes with the patient’s activities of daily living such as reading, driving, or watching television.
Vitrectomy surgery involves removing the vitreous gel. A dye is applied to identify the membrane and underlying internal limiting membrane (ILM). I prefer brilliant blue, which is very safe and effective. In almost all cases, using specialized microforceps, I peel the ILM. This ensures removal of all the overlying fibrous pucker membranes, and decreases the risk for membrane recurrence.
The standard of care for epiretinal membrane includes a thorough examination to ensure no other ocular disease is present. Once the diagnosis is established, the condition is usually monitored for progression. When the condition worsens, and vision is significantly diminished, surgery is considered. The majority of patients gain vision following successful removal of epiretinal membrane.
American Academy of Ophthalmology Retina/Vitreous Panel. Preferred Practice Pattern® Guidelines. Idiopathic Epiretinal Membrane and Vitreomacular Traction. San Francisco, CA: American Academy of Ophthalmology; 2015. Available at: www.aao.org/ppp. Accessed July 24, 2019.
Gupta, O. Epiretinal Membrane. American Academy of Ophthalmology. EyeWiki. https://eyewiki.aao.org/Epiretinal_Membrane. Accessed July 24, 2019.
Retina Health Series. Epiretinal Membranes. The Foundation of the American Society of Retina Specialists. https://www.asrs.org/content/documents/fact_sheet_12_epiretinal_membranes_new.pdf. Accessed July 24, 2019.
Summary Benchmarks for Preferred Practice Pattern® Guidelines. Idiopathic Epiretinal Membrane and Vitreomacular Traction. American Academy of Ophthalmology; 2018. Accessed June 17, 2019.