Epiretinal Membrane Condition and Your Retina

Epiretinal membrane is a condition often confused with macular degeneration. Both conditions affect the macula, the specialized part of the retina that gives us sharp, central 20/20 vision. However, the conditions are completely different and can cause different symptoms. There are several different names for an epiretinal membrane. The various names help to describe the stages or complications of the condition. Some additional names used to describe epiretinal membrane include the following:

• Cellophane maculopathy
• Preretinal macular fibrosis
• Macular pucker
• Vitreomacular traction syndrome

What Is an Epiretinal Membrane?

An epiretinal membrane is a thin, semi-transparent membrane that can form on the back of the retina, usually inside the macula. This membrane can be somewhat opacified and difficult to see through.

For many years, these membranes were referred to as cellophane maculopathy because they resembled clear cellophane plastic. The membrane is transparent, but when you pick it up, it becomes wrinkled and less transparent.

Some healthcare providers refer to an epiretinal membrane as preretinal macular fibrosis, indicating where it is and what it is made of. When the membrane contracts, it can cause the macula to pucker and become slightly distorted or elevated, hence the name "macular pucker." When the vitreous fails to detach from the macula, but still contracts, the macula can become lifted or elevated. This is referred to as "vitreomacular traction syndrome."

Causes

Interestingly, many people who develop an epiretinal membrane do not have any other eye disease. It is most commonly caused by natural aging changes that occur in the vitreous humor, the gel that fills the back part of the eyeball.

The vitreous fills about 80 percent of the eye. It contains millions of fibers that are attached to the retina. As we get older, the vitreous shrinks and pulls away from the surface of the retina. When it pulls away, it is called a vitreous detachment and is simply a normal part of the aging process. When someone has a vitreous detachment, they usually see small black spots in their vision or floaters. These floaters sometimes appear as cobwebs that may move around in their visual field.

Occasionally, as the vitreous gel pulls away from the surface of the retina, a small amount of damage occurs to the retina. After the damage occurs, the body attempts to heal the damaged surface and forms a small amount of fibrous tissue or scar tissue. This scar tissue is referred to as an epiretinal membrane. As in other places in our body, sometimes this fibrous scar tissue may contract. Because this membrane is firmly attached to the retina, as the membrane contracts, it may cause the retina to contract or wrinkle.

If this scar tissue were to form in the peripheral part of your retina, you would probably never know it. However, this membrane often forms on the macula, the most sensitive part of the retina, which is responsible for sharp, detailed, central vision. When the membrane contracts over the macula, we notice blurred and distorted vision.

Risk Factors

It is important to point out that most of us who experience a posterior vitreous detachment do not go on to develop an epiretinal membrane. In the United States, epiretinal membrane occurs in around 4% of people under 60 and 14% of people over 60. Age is the biggest risk factor for developing an epiretinal membrane,

Other risk factors include the following:

• Posterior vitreous detachment from trauma
• Retinal tear
• Eye surgery
• Diabetes
• Vessel occlusions to the eye
• Internal inflammation

Symptoms

The epiretinal membrane can cause a variety of symptoms, including the following:

• Blurry vision
• Distorted vision
• Small flickers or flashes of light

Consequences

Most people who suffer from an epiretinal membrane will usually develop blurred vision. As the condition progresses, metamorphopsia can develop. Metamorphopsia is a descriptive term used to describe distortion of vision. For example, an object may appear bigger or smaller than it actually is. Furthermore, a straight line may appear bent or a piece of it may be missing.

People who develop an epiretinal membrane may not only have blurred vision, but this blurred vision may become very distorted. As metamorphopsia worsens, vision may drop to 20/50 or worse. However, some people develop mild epiretinal membranes and may never even know they have the condition. In this case, the membrane exists, but it does not contract, so wrinkling of the retina never occurs.

More rarely, some people will develop puckering of the macula and, more severely, distorted vision. Distorted vision will also develop if the vitreous does not detach and begins to pull on the macula. When this occurs, a macular hole may form. Depending on the size and severity of the macular hole, severe central vision loss may occur.

Diagnosis

The first step in diagnosing epiretinal membrane is to undergo a comprehensive eye examination. Your vision will be assessed to measure the level of your vision. Your eyes will be dilated with medicated eye drops. Your retinal can be observed by a special upright bio-microscope called a slit lamp. Epiretinal membranes can be seen with this instrument.

To assess the severity of an epiretinal membrane, a test called an OCT (optical coherence tomography) will be performed. An OCT uses light to visualize different layers of the retina. In minutes, your healthcare provider can see how the membrane is affecting the macula. In this manner, progress can be checked by repeating scans and then comparing them to the baseline measurements to see if things are getting better or worsening.

What You Should Know

Most epiretinal membranes require close monitoring. If the epiretinal membrane begins to cause more severe vision loss, your healthcare provider may refer you to a retinal specialist. A retinal specialist can perform a procedure in which the membrane is delicately peeled off the retina to restore vision. If a hole develops in the macula, a retinal specialist will attempt to repair the hole. Macular hole surgical repair usually helps to restore some vision. The success of a macular hole repair is often dependent on the length of time it has been there.