Retina On Line

by Moorfields Eye Hospital
 
Your eye specialist has told you that you have an epiretinal membrane.  This leaflet will help you decide what to do.  You might want to discuss the information with a relative or carer.  If you have an operation, we will ask you to sign a consent form, so it is important that you understand the information in this leaflet before you agree to go ahead with surgery. If you have any questions, you might want to write them down to help you remember to ask one of the hospital staff.  
 
What is an epiretinal membrane?

If you think of your eye as a camera, the retina is like the photographic film.  It is a very thin layer of tissue, which is sensitive to the image focused on it, and sends information to the brain.  At the very centre of the retina is the macula.  This is a very special area of the retina, which we use for reading and recognising complex shapes.  Sometimes, scar tissue forms which grows across the macula. As the membrane contracts, it causes distortion of the retinal tissue.  If this happens, the macula cannot work normally. This affects the vision, particularly for reading and other visually demanding tasks. However, it does not cause total blindness.

What causes an epiretinal membrane?

Most epiretinal membranes happen because the vitreous (the jelly inside the eye) pulls away from the retina. This most commonly happens to people over the age of 50. The membrane may also form following eye surgery or inflammation inside the eye.  
 

How will an epiretinal membrane affect my vision?

While the scar tissue is developing, it does not appear to affect your vision. However, when it stops growing it contracts (shrinks) and causes distortion of your central vision, i.e. straight lines appear wavy or crooked in appearance, and reading is difficult. Depending on the severity of this distortion, you might notice a
substantial loss of central vision.  
 

How is an epiretinal membrane treated? 

The only way to treat an epiretinal membrane is by having an operation. Eye drops or glasses are ineffective.

Should I have surgery for my epiretinal membrane?

Your doctor will help you to decide if surgery is appropriate for you. The main reason to proceed with the operation is to attempt to correct the distortion of your central vision. If you are not aware of any visual problems, you might not need to have surgery. However, if the distortion affects your ability to work, drive, read, or perform other important activities, you should consider having an operation.  
 
Some patients decide not to have an operation and accept the distorted central vision in the affected eye. This is reasonable, especially if the vision in the other eye is not affected. There is no “right” or “wrong” decision, as every person has different needs and priorities. 

Will the problems get worse if I leave it?

Not necessarily. In general, you should only go ahead with surgery if you find the distortion of your vision troublesome at the moment, and not as a preventative measure.  

The anaesthetic: local

If you decide to have a local anaesthetic, you will be awake during the operation. You will not be able to see what is happening, but you might be aware of a bright light. Before the operation, we will give you eye drops to enlarge your pupil. After this, we will give you an anaesthetic to numb your eye. This involves injecting local anaesthetic solution into the area around your eye. 

During the operation, we will ask you to lie as flat as possible and keep your head still. 

The operation normally takes about an hour, but may sometimes take a little longer.  

The anaesthetic: general

If you decide to have a general anaesthetic, we will ask you not to eat or drink for six hours before your surgery, although you drink sips of water up to two hours before the operation. Prior to surgery, an anaesthetist will speak to you and examine you on the ward. The nursing staff will give you eye drops to enlarge your pupil. When you arrive in the theatre’s anaesthetic room, the anaesthetist will give you an injection in your hand or arm. You will then stay asleep for the whole operation. The anaesthetist will monitor your heart rate, breathing, blood oxygen and blood
pressure while you are under the anaesthetic. You may feel tired and sleepy for about six-12 hours after the operation. 

The surgery

The operation will be performed by an experienced surgeon. A more junior surgeon might perform some, or all, of your operation under the supervision of an experienced surgeon.  

You will need an operation called a “vitrectomy”, which involves your surgeon making tiny cuts in your eye and removing the vitreous from inside. Your surgeon will then grasp and gently peel away the epiretinal membrane from the retina.  

We usually put small stitches in the eye. These dissolve naturally over about four - six weeks. At the end of the operation, we usually put a pad and shield over your eye to protect it. These will be removed the morning after your surgery.

After the operation:

• The eye will feel uncomfortable, gritty, and itchy.  It may appear red or bruised. This is normal for seven -14 days. 

• Take paracetamol for pain relief every four - six hours.  

• The eye takes two - six weeks to heal, but the vision may continue to improve for several months.  

• You will be reviewed in clinic about two weeks after the operation.  

• We will give you eye drops to reduce any inflammation, to rest the eye and to prevent infection. We will explain how
and when you should use them.   

• Please don’t rub your eye.  
 
While a certain amount of discomfort is normal after the surgery, you should contact the hospital immediately if you have any of the following symptoms: 

• A lot of pain.

• Loss of vision.  

• Increasing redness of the eye. 

What improvement in my vision can I expect after the operation?

After an epiretinal membrane is removed, vision gradually improves over a period of three - six months in 70%-80% of
patients. However, in some cases vision may not improve following surgery, due to damage already caused by the
membrane. In about 10% of patients, the membrane may return, which will cause the visual problems to recur.  
Surgery usually improves the vision in the affected eye, however, it will never be completely normal.  
 

What are the side effects of surgery?

A vitrectomy operation can cause small tears to form in the delicate structure of the retina, which may cause the retina to move away from its normal position at the back of the eye (retinal detachment). Sometimes, the surgeon can see this problem starting during the vitrectomy operation, and will put a bubble of gas into the eye to prevent any damage occurring. However, if you did experience a retinal detachment, you would need to have another (different) operation to prevent sight loss in the affected eye.  
 
If gas is inserted into your eye during the vitrectomy operation, you may have to posture (keep your head in a certain position) after the operation while the gas bubble dissolves. During this time (about two weeks) your sight will be blurred. A member of staff will provide you with a posturing leaflet.  
 
When posturing, please avoid sitting or lying in bed for long periods of time without moving your legs. It is important for you to avoid prolonged immobility. When you are sitting, try moving your ankles around and going up and down on your tiptoes. During your rest periods, you are able to walk around.  
 
The likelihood of getting a cataract (where the lens in your eye becomes cloudy) increases after a vitrectomy, so you might need surgery for this condition sometime in the future.