An epiretinal membrane (ERM) is scar tissue that forms on the surface of the retina, the light-sensitive tissue lining the back of the eye. This membrane develops specifically over the macula, the central area responsible for sharp, detailed central vision. A primary concern for individuals diagnosed with an ERM is understanding the condition’s natural progression and whether it can improve without medical intervention. The prognosis depends largely on the membrane’s composition, its effect on the underlying retinal structure, and the presence of any associated eye conditions.
What is an Epiretinal Membrane
The epiretinal membrane is a sheet of fibrocellular tissue that grows along the inner surface of the retina, precisely at the vitreoretinal interface. The membrane is composed of various cell types, primarily glial cells and collagen. This growth causes the retina’s surface to wrinkle, which is why the condition is often referred to as “macular pucker” or “cellophane maculopathy.”
The condition is categorized into two types: idiopathic and secondary. Idiopathic ERMs are the most common, meaning they arise without an identifiable cause, though they are strongly associated with the natural aging process of the vitreous gel separating from the retina. Secondary ERMs develop due to an underlying eye disease or event, such as a retinal tear or detachment, diabetic retinopathy, inflammation, or trauma.
The Natural Course: Can ERM Resolve Spontaneously
The vast majority of epiretinal membranes do not spontaneously resolve, meaning they do not heal themselves without treatment. Spontaneous resolution is a rare event, often attributed to the body’s natural cellular remodeling or a complete posterior vitreous detachment (PVD) tearing the membrane free. This natural detachment occurs in only a small percentage of cases.
If the ERM does not resolve, the natural course is typically stable or characterized by slow progression over years. The cells within the membrane have contractile properties, causing the scar tissue to slowly tighten and exert traction on the macula. This tangential traction pulls and distorts the underlying retinal layers, which can lead to swelling, or macular edema.
The severity of an ERM is often graded based on the degree of traction and thickness observed using optical coherence tomography (OCT) imaging. Mild cases may only show a subtle wrinkling of the inner retinal surface, often referred to as cellophane maculopathy, which may not impact vision. Progression to a severe macular pucker causes significant distortion of the macula’s normal contour and can lead to a pseudohole or cystoid macular edema.
When is Intervention Necessary
Intervention is not required for all epiretinal membranes; many mild cases remain stable and are simply observed. The decision to treat is based on functional criteria, specifically the impact on the patient’s daily life and the severity of visual symptoms. The two primary symptoms that trigger surgical consideration are a significant decrease in visual acuity and the presence of metamorphopsia.
Metamorphopsia is the distortion of vision where straight lines appear wavy or bent. This can be highly debilitating and is not fully reflected in standard visual acuity tests. When the distortion or blurring interferes with activities like reading, driving, or recognizing faces, surgical intervention becomes a necessary option. Observation is recommended for patients who have good vision or are asymptomatic.
The main surgical treatment is pars plana vitrectomy with membrane peeling. This involves removing the vitreous gel and then using micro-forceps to peel the ERM away from the retinal surface. The goal of the surgery is to relieve the physical traction on the macula, allowing the retinal layers to relax and restore a more normal anatomical structure.
Post-Treatment Expectations and Recovery
Following vitrectomy with membrane peeling, visual recovery is typically gradual, often taking several months to a year to be fully realized. While many patients experience an improvement in visual acuity, the most reliable benefit is usually a significant reduction in the visual distortion caused by the membrane’s traction. Patients are prescribed antibiotic and anti-inflammatory eye drops to prevent infection and manage inflammation during recovery.
If a gas bubble is used during the surgery to act as an internal splint, patients are given specific instructions, which may include maintaining a certain head position for several days. A potential side effect of the surgery is the accelerated development of a cataract, which is common, especially in older patients. Other surgical risks include retinal detachment or tears. The long-term objective of the procedure is to prevent further vision loss and improve central vision.