Epiretinal membrane (macular pucker)

An epiretinal membrane (ERM) is a thin, translucent layer of fibrous tissue that forms on the surface of the macula, the central part of the retina responsible for sharp, detailed vision. This membrane consists of cells that settle and proliferate on the retinal surface. Over time, the ERM can contract, pulling on the underlying retina, leading to thickening and structural distortion of the macula. This distortion interferes with light reception and can impair central visual quality.

In most cases, an epiretinal membrane develops spontaneously, often as a byproduct of posterior vitreous detachment (PVD), a natural aging process where the vitreous gel separates from the retina. This process can create minimal retinal trauma, encouraging cell proliferation and membrane formation. Additional risk factors include retinal tears, eye trauma, previous eye surgeries such as cataract surgery, diabetes, and intraocular inflammatory diseases. These conditions can all lead to cell growth on the retinal surface and the creation of the membrane.

The symptoms of an epiretinal membrane vary widely. In many instances, the membrane is subtle and causes no noticeable symptoms, or only mild ones that do not interfere with daily function. When the membrane contracts and pulls significantly on the retina, symptoms such as blurred central vision, distorted vision (metamorphopsia) where straight lines appear wavy or crooked, and difficulty with reading or recognizing fine details may occur. Occasionally, individuals report monocular double vision or differences in image size between the eyes.

Diagnosis of an epiretinal membrane is performed by an ophthalmologist through a comprehensive eye examination. During the examination, the doctor will examine the fundus of the eye using a slit lamp, which allows visualization of the membrane on the retinal surface. The primary diagnostic tool is Optical Coherence Tomography (OCT), a non invasive imaging test that provides detailed cross sectional images of the retina. OCT allows for assessment of the membrane's thickness, the extent of its traction on the retina, and its impact on macular structure, including the presence of edema or other distortions.

In many cases, when the membrane causes no significant symptoms or when symptoms are mild and stable, active treatment is not necessary. In these situations, periodic monitoring with eye examinations and OCT scans is recommended to track the membrane's status and its effect on vision. If the membrane causes significant visual impairment, such as severe visual distortion or a substantial decrease in visual acuity, surgical intervention may be considered.

The surgical treatment for an epiretinal membrane is a vitrectomy, where the vitreous gel filling the eye's cavity is removed and replaced with a sterile saline solution. After vitreous removal, the surgeon carefully peels the epiretinal membrane from the retinal surface. Often, the internal limiting membrane (ILM), another thin layer of the retina, is also peeled to reduce the risk of membrane recurrence. In some cases, a temporary air or gas bubble is placed inside the eye, for example if a retinal tear needs treatment. If this is used, do not fly or travel to high altitude until your surgeon confirms the bubble has completely disappeared. Nitrous oxide, also called laughing gas, must not be given while a bubble remains because it can dangerously raise eye pressure. Tell any medical, dental or emergency care team that you have a bubble in your eye, and follow the surgeon's positioning instructions. The goal of the surgery is to relieve traction on the retina, allowing it to return to a more normal structure, thereby improving vision.

Recovery from vitrectomy and membrane peeling surgery is gradual. Visual improvement may take several months, and the improvement is not always complete. It is important to understand that the surgery aims to improve distorted vision and halt disease progression, but vision may not return to its original level. Potential surgical risks include cataract development, infection, bleeding, retinal detachment, and nerve damage. Before surgery, the doctor will discuss the expected outcomes and potential risks with the patient.

After surgery, regular follow up with the ophthalmologist is necessary to assess the healing process and visual improvement. Even in cases where surgery was not performed, periodic monitoring is recommended. You should contact your ophthalmologist immediately if new symptoms appear or if existing symptoms suddenly worsen, such as a sharp decrease in vision, the appearance of flashes of light, numerous new floaters in your field of vision, or a dark curtain covering part of your visual field. These symptoms may indicate complications requiring urgent medical attention.