Understanding epiretinal membrane surgery

What is an epiretinal membrane?
What causes an epiretinal membrane to form?
How does epiretinal membrane affect your sight?
When should you have epiretinal membrane surgery?

 

What is an epiretinal membrane?

Epiretinal membrane (ERM) is a condition characterised by the growth of abnormal tissue across the surface of the macula, the central part of the retina. It behaves as a form of scar tissue which, as it contracts, “puckers” the underlying macula causing distortion and visual loss.

It is helpful to know a little about the eye and how it works in order to understand the effect epiretinal membrane has on the vision, and how it can be treated.

Anatomy of a normal eye

The wall of the eye is formed by three layers, the retina, the choroid and the sclera.

The retina is the light-sensitive nerve tissue that lines the inner wall of the eye. Rays of light enter the eye, passing through the cornea, pupil and lens before focusing on to the retina. The retina contains photoreceptors which convert light into electrical impulses.

In the healthy eye these impulses are sent via the optic nerve to the brain where sight is interpreted as clear, bright, colourful images. The retina can be likened to photographic film in a camera.

The macula is a small area at the centre of the retina. It is very important as it is responsible for our central vision. It allows us to see fine detail for activities such as reading, recognising faces, watching television, and driving. It also enables us to see colour.

The choroid is the underlying vascular (blood vessel) layer of the eye from which the retina receives oxygen and nutrients.

The vitreous is the clear jelly-like substance which fills the hollow space behind the lens. As we age this vitreous gel opacifies and shrinks away from the retina. This is very common, occurring in about seventy-five per cent of people over the age of sixty-five.

Separation of the vitreous gel from the retina is known as posterior vitreous detachment or “PVD”. It does not itself cause any permanent loss of vision although floaters may be troublesome.

Rarely, the effect of posterior vitreous detachment, or of continuing traction as the gel collapses, is to start a process of scarring over the central macular retina resulting in epiretinal membrane.

back to top

 

What causes an epiretinal membrane to form?

The cause of the majority of epiretinal membranes is unknown (idiopathic) but the condition is frequently associated with previous posterior vitreous detachment.

It is more common when vitreous detachment has resulted in retinal tearing (requiring laser or freezing therapy) or retinal detachment. Less commonly ERM is associated with previous occlusion of retinal blood vessels or inflammation in the eye.

Comparison of a healthy eye and an eye with epiretinal membrane.

back to top

 

How does epiretinal membrane affect your sight?

Common symptoms of epiretinal membrane or macular pucker are:

  • distortion of straight lines;

  • blurred central vision;

  • disparity in image size between the two eyes.

OCT image of a normal macula and a macula with epiretinal membrane

back to top

When should you have epiretinal membrane surgery?

The procedure to treat this condition involves removal of the scar tissue from the retina. This is known as epiretinal membrane peeling and requires a vitrectomy operation.

The indication for surgery depends largely on the level of distortion or visual interference you are experiencing. The presence of epiretinal membrane is not necessarily an indication for surgery. The decision to treat depends on both the progression of symptoms in the affected eye and your ability to use the two eyes together.

We will help you decide if a membrane peeling operation is appropriate for you.

back to top

 

Links | Sitemap | © 2012 Sapphire Eye Care | Web design by iQ interactive