An epiretinal membrane is a semi-translucent fibrous tissue cover that forms on the innermost section (macula) of the retina, the light-sensitive area at the back of the eye. The macula is an oval spot close to the center of the retina, which is responsible for sharp focus. At times, scar tissue grows over the macula surface, and when the membrane shrinks, it distorts the retinal tissue. The distortion can create problems with central vision and affect the performance of visually demanding tasks, such as reading and driving, but it does not cause complete blindness. The extent of the loss of central vision depends on the severity of the disorder.
The disorder is more prevalent among middle-aged and elderly adults and is often confused with macular degeneration. However, although both disorders involve the macula, they have different causes and symptoms.
Some potential ERM complications include:
- Macular hole
- Early cataract
- Macular pseudo hole – a hole developing on the membrane and not on the macula
- Decreased or distorted vision leading to significant vision difficulties and emotional stress
- Surgical complications like bleeding, infection, recurrence of ERM and retinal detachment
Also Known As
- Macular pucker
- Premacular fibrosis
- Cellophane maculopathy
- Surface wrinkling retinopathy
Causes & Risk Factors
In most cases, ERM develops spontaneously and isn’t associated with any medical conditions. It can also arise due to:
- Traction - the pulling of the vitreous humor (the jelly inside the eye) from the retina
ERM risk factors include:
- Intraocular surgery
- Eye injury or trauma
- Retinal tear or detachment
- Posterior vitreous detachment
- The presence of Epiretinal Membrane in one eye
- Retinal vascular diseases, such as diabetic retinopathy, artery or vein occlusions
It’s essential to understand that a risk factor increases the likelihood of getting a condition, but it doesn’t mean that one will develop the disorder. It’s also vital to realize that not having a risk factor doesn’t mean that one can’t get the disorder. The patient should always discuss the issue of risk factors with the doctor.
Signs & Symptoms
ERM signs and symptoms differ from one patient to another, and often the anomaly is asymptomatic. It may also present with the various symptoms, such as:
- Wavy vision
- Blurred vision
- Light sensitivity
- Distorted vision
- Decreased vision
- Loss of central vision
- Double vision in one eye
- Difficulty in reading small print
- Images looking smaller or larger than average size
The ophthalmologist will assess the symptoms and establish the detailed medical history of the patient. S/he will evaluate the history of intraocular trauma surgery, or underlying disease, such as posterior vitreous detachment. S/he will conduct a complete eye examination, including Amsler Grid test, dilated retinal exam or imaging tests, such as ocular coherence tomography (OCT). The doctor may also perform additional tests, such as Fluorescein angiography to rule out other underlying disorders, such as retinal abnormalities and arrive at a definitive diagnosis.
In most cases, ERMs stabilize after an initial period of growth and don’t significantly affect vision, and so the doctor will observe and monitor the condition carefully.
Vitrectomy surgery is the only way to treat ERM. The doctor will only recommend it in severe cases where the disorder affects the patient’s ability to read, work, drive, or perform other vital activities. Vitrectomy is an outpatient surgical procedure that enables the surgeon to address the underlying issue and peel-off the covering membrane to improve vision.
Complete healing can take between four weeks and several months and the patient must follow the specific instructions provided by the ophthalmologist to avoid complications. The patient will have to avoid activities that can raise eye pressure during this period. It includes intense exercise, reading, driving, heavy lifting, scuba diving, mountain climbing, air travel, etc.
Prognosis & Long-Term Outlook
The prognosis for ERM is excellent in most patients, even in cases where they require vitrectomy to remove the protective tissue. The distortion resolves, and the vision improves in close to 90 percent of cases once the tissue is removed. In general, the milder the condition and less time it has been developing, the better the prognosis. The patient’s vision improves gradually for up to one year.
Prevention & Follow Up
Currently, there are no guidelines or methods available for the prevention ERM, i.e., the eye disorder unpreventable. However, in secondary ERM, where it results from an underlying condition, such as vitreous or retinal diseases then, managing the systemic abnormality may help prevent such pathological eye changes.