Epiretinal Membrane: OCT, CT Scan (Brain), Symptoms, Stages, Surgery, Peel

Epiretinal Membrane:

• What is Epiretinal Membrane?
• OCT
• CT Scan (Brain)
• Symptoms
• Stages
• Surgery
• Peel

What is Epiretinal Membrane?

An epiretinal membrane (ERM), also known as macular pucker or cellophane maculopathy, is a thin layer of fibrous tissue that forms on the surface of the retina, specifically over the macula. The macula is the central part of the retina responsible for sharp, detailed vision used for reading and recognizing faces. When this membrane contracts, it can distort the underlying retinal tissue, leading to visual distortion and reduced clarity.

Epiretinal membranes commonly develop with aging and are often associated with posterior vitreous detachment. They can also occur after eye surgery, retinal tears, inflammation, or trauma. Many ERMs are mild and cause little to no symptoms, while others progress and significantly affect vision. Understanding ERM is important because early diagnosis helps guide monitoring and treatment decisions before vision loss becomes more severe.

OCT

Optical Coherence Tomography (OCT) is the most important and widely used imaging tool for diagnosing and monitoring epiretinal membranes. OCT provides high-resolution, cross-sectional images of the retina, allowing clinicians to clearly visualize the membrane, retinal thickening, and distortion of the macular layers.

On OCT, an epiretinal membrane appears as a thin, reflective layer on the inner surface of the retina. OCT also helps assess traction, macular edema, and changes in retinal architecture. This imaging is essential for staging the disease, determining severity, and deciding whether surgery is needed. OCT is non-invasive, painless, and can be repeated over time to track progression or post-surgical recovery.

CT Scan (Brain)

A CT scan of the brain is not typically used to diagnose epiretinal membranes, as ERM is an eye condition best evaluated with retinal imaging such as OCT or fundus photography. However, CT scans may be ordered in certain situations where neurological causes of visual symptoms are suspected, such as stroke, tumors, or increased intracranial pressure.

If a patient presents with visual distortion along with neurological symptoms like headaches, weakness, or confusion, a brain CT may be used to rule out central nervous system causes. While CT imaging does not visualize retinal layers, it plays a supportive role in excluding brain-related conditions that could mimic or coexist with retinal disorders.

Symptoms

Symptoms of epiretinal membrane vary depending on the thickness and contraction of the membrane. Early or mild ERM may cause no noticeable symptoms and is often discovered incidentally during routine eye exams. As the condition progresses, patients may experience blurred central vision, difficulty reading, and distortion of straight lines, known as metamorphopsia.

Other symptoms include double vision in one eye (monocular diplopia) and reduced contrast sensitivity. Vision loss is usually gradual rather than sudden. Importantly, ERM does not typically cause complete blindness, but it can significantly impact quality of life if untreated in advanced stages.

Stages

Epiretinal membrane progression is often described in stages based on clinical findings and OCT features. Early stages show a thin membrane with minimal retinal distortion. Intermediate stages demonstrate retinal thickening and wrinkling of the macula. Advanced stages show significant traction, macular distortion, and sometimes macular edema.

Staging helps ophthalmologists decide whether observation or surgical intervention is appropriate. Many early-stage ERMs remain stable for years, while others gradually worsen. Regular eye exams and OCT monitoring are essential to detect progression and intervene at the right time to preserve vision.

Surgery

Surgery for epiretinal membrane is recommended when visual symptoms significantly affect daily activities. The standard procedure is a pars plana vitrectomy, during which the vitreous gel is removed to allow access to the retinal surface. This surgery is typically performed under local or general anesthesia.

Visual improvement after surgery is usually gradual and may take several months. While most patients experience improved vision and reduced distortion, outcomes depend on the severity and duration of the membrane. As with any surgery, risks include infection, retinal detachment, and cataract progression, but overall success rates are high.

Peel

The membrane peel is the critical step during ERM surgery. Using fine microsurgical instruments, the surgeon carefully peels the epiretinal membrane off the retinal surface. In many cases, the internal limiting membrane (ILM) is also peeled to reduce the risk of recurrence.

Peeling the membrane relieves traction on the macula, allowing the retina to gradually return toward its normal shape. While the retina may not fully return to its original anatomy, most patients experience meaningful functional improvement. Postoperative follow-up with OCT is essential to assess healing and visual recovery.