Epiretinal membrane: causes, symptoms and treatment

Epiretinal membranes (ERMs) are thin, transparent layers of scar tissue that grow across the central (macular) area of the retina. Occasionally, they are caused by trauma or inflammation that affects the eye, but in most cases, it is simply due to ageing and degeneration of the vitreous gel. Here, one of our highly experienced ophthalmologists Mr Vaughan Tanner explains everything that you need to know about ERMs.

What are the risk factors and causes of epiretinal membrane?

In most cases, the development of an ERM is triggered by the age-related degeneration of the vitreous gel which normally fills the eye. The degenerate gel pulls away from the retina (posterior vitreous detachment) and releases cells that form a membrane over the retina. In some cases, it can be related to other conditions such as:
 

• Diabetic retinopathy
• Blockage of the blood vessel
• Injuries or surgery
• Inflammation
• Retinal detachment

ERMs are not related to macular degeneration. They do not usually affect the other eye and are quite common, affecting up to 8% of people in later years.
 

What are the symptoms of epiretinal membrane?

Many ERMs are asymptomatic and are noted during a routine visit with your optician. However, symptoms may include blurring of vision, distortion, double vision and problems reading small print.

In many cases, symptoms are only mild and non-progressive with no requirement for surgery. They can be monitored with routine eye examinations.

In a few cases, where ERMs are more severe, the retina is pulled out of position by a contracting membrane with distortion of the retinal vessels.

They are often best seen with a diagnostic procedure known as optical coherence tomography (OCT). This infrared, non-contact laser scan allows a highly magnified, cross-sectional image of the retina to be analysed. If distortion is marked, then membranes may be removed via vitrectomy surgery.
 

What happens during an assessment for epiretinal membrane?

Your eye doctor is usually able to detect an ERM during an eye examination following the use of eye drops that temporarily make your pupils large. In most cases, an OCT scan of the back of the eye is also used to confirm the presence of an ERM. Your ophthalmologist will assess your symptoms to help you decide whether to proceed with surgery.
 

What should I expect with a diagnosis?

In many cases, the discovery of an ERM is by chance at a routine optician examination and vision may not be affected. These ERMs often do not progress to affect vision. In some people ERMs progress to cause blurring and/or distortion of vision. Treatment is only required in those cases where the vision has been affected.
 

What happens during epiretinal membrane removal?

If an ERM affects vision, the only way to treat it is to remove the membrane surgically. This is achieved by an operation called a vitrectomy, where specialised instruments remove the jelly-like substance (vitreous gel) that normally fills the centre of the eye. The membrane itself is then removed using fine forceps.

The removal of the vitreous gel does not affect the function of the eye, and the gel is replaced by natural fluid produced inside the eye.

In some cases, the surgeon has to leave a gas bubble inside the eye which disappears on its own after a few weeks. The operation for ERM removal is usually less than one hour and can be performed using a local anaesthetic injection with the patient remaining comfortable and awake during the procedure.
 

What happens during recovery?

Following membrane removal, the vision is typically more blurred for the first few weeks. Over the next few months the vision then gradually improves. The operation usually successfully reduces distortion and blur in about 90% of people. As with any surgery, there are possible complications with about a 3% chance of being worse after surgery.
 

You can book an appointment to see Mr Tanner via his Top Doctor’s profile here if you’re worried about your eye health and he will give you his expert opinion.