Epiretinal membranes are thin, transparent layers of fibrous tissues that form a film on the inner surface of the retina.
Epiretinal membranes (ERMs) most often occur in people over age 50. According to The American Society of Retina Specialists (ASRS), at least 2 percent of people over 50 years old and 20 percent over age 75 have ERMs, but most do not need treatment.
Up to 20 percent of people with ERMS have them in both eyes, but symptoms and severity for each eye differ.
ERMs are severe when they affect the central part of the retina responsible for seeing fine details, for example, when reading or recognizing faces.
In the severest cases, vision is blurred and distorted, similarly to a distorted view through an unadjusted pair of binoculars.
Straight lines, such as those from a doorway, might appear wavy to someone with an ERM. ERM vision loss starts out unnoticeable and becomes increasingly severe.
A person should report any of the following symptoms to their doctor or an eye specialist:
- Decreased vision or loss of central vision. Central vision allows the eyes to see ahead to read or drive or see fine details.
- Distorted or blurred vision.
- Double vision.
- Wavy vision.
- Problems reading small print.
A person’s risk of developing an ERM increases with age, and people with an existing eye or vision condition may develop an ERM before age 50.
Eye conditions that put a person at risk for developing an ERM are:
- Posterior vitreous detachment: Separating of the gel that fills the back of the eye to the retina.
- Retinal tear or detachment: A retinal tear is a break in the retina whereas retinal detachment occurs when the retina pulls away from the back of the eye.
- Injuries: Eye injuries or traumas can cause ERMs.
- Surgery: Eye surgeries, such as cataract surgery, can cause ERMs.
- Retinal vascular diseases: Conditions affecting the blood vessels in the eyes, such as diabetic retinopathy. Diabetic retinopathy can affect people with diabetes
- Existing ERM: Having an ERM in one eye means a higher likelihood of getting them in the other eye too.
Having risk factors for ERMs does not guarantee that someone will develop this condition in one eye or both. Also, someone who does not have any risk factors could develop an ERM.
Who gets ERMs?
According to the ASRS, men and women are equally affected by ERMs, but at least one medical journal disagrees. A research study reported in the journal, BMJ Open, finds women are more often affected by ERMs than men.
It is also possible people of particular races are more affected by this condition than others. For example, the BMJ reported that 39 percent of people affected by this condition were of Chinese descent, 27.5 percent were Caucasian, 26.2 percent were African, and 29.3 percent were Hispanic.
ERMs can be diagnosed during a routine vision exam. In many cases, vision is not affected. Most types of ERM do not change and cause vision symptoms.
Some ERM do get worse, however, and will cause blurring and vision disturbances. The only time a doctor will suggest treatment is when there are vision symptoms.
A diagnostic test called optical coherence tomography (OCT), which uses light waves to scan and view the layers of the retina, can help with the diagnosis of ERMs.
An eye doctor may also use another test called fluorescein angiography. This test involves the use of dye to light up areas of the retina.
Surgery aside, there are no other effective treatments for ERMs. Glasses or contacts, and even prescription eye drops are not effective treatments.
About 15 percent of ERMs require surgery, this according to one report from the Indian Journal of Ophthalmology. Further, surgical intervention is successful in most cases, even though vision improvement for 25 to 50 percent is at about 20/40.
The 20/40 measurement is used to define visual accuracy, clarity, and sharpness. A 20/40-vision measurement means someone sees at 20 feet (ft) what a person with normal vision would see at 40 ft.
Vitrectomy surgery procedure
The surgery for ERMs is called a vitrectomy. During a vitrectomy, the surgeon will make tiny cuts in the affected eye and remove the fluid from inside the eye.
The surgeon will then hold and gently peel the epiretinal membrane from the retina and replace the fluid in the eye.
Finally, the doctor places a pad and shield on the eye to protect it from infection or injury.
Risks for EMR surgery
Vitrectomy surgery is not without risks. ERM surgery increases the risk for cataract, an eye disorder that causes clouding in the lens of the eye.
In general, however, the risk associated with ERM surgery is small. In fact, according to the ASRS, about 1 in 100 people develop retinal detachment, and 1 in 2,000 develop a post-surgical infection.
Recovery after ERM surgery
Following surgery, the person will be given eye drops to help stabilize the eye after the operation, and the surgical staff will provide instructions as to how long a person should use the drops.
Most vitrectomies are outpatient surgeries, and the person will not need to stay overnight in a hospital.
They will need another adult to drive them home after surgery.
Following a vitrectomy, a person may need to position their head a certain way for some part of the day, at least for a few days following the surgery. The surgeon will give instructions as to how to limit activities to ensure a good recovery. Most people will notice an improvement in vision after surgery, but it may take up to 3 months for their vision to stabilize.
There are no ways for someone to protect themselves from developing an ERM. Sometimes, an ERM results from another retinal disease, such as diabetic retinopathy, so managing an underlying condition—such as diabetes—can help prevent an ERM developing in one or both eyes.
The prognosis for most people who develop an ERM is usually good. For many, decreased vision is minor and does not affect their quality of life or warrant treatment. For those who require surgery due to an advanced ERM, surgery is usually successful in improving vision, and complications associated with ERM surgery are rare.