Epiretinal membrane ('ERM') formation
is also called cellophane maculopathy or macular pucker. It is
not a type of macular degeneration.
The central part of the retina is affected. A very thin
film or membrane develops on the surface of the retina. This
membrane, very like 'cling-film', starts to shrink, and this
causes wrinkling of the retina.
The wrinkling may be mild, in which case surgery is not recommended.
In such a patient the sight would be good or reasonable, and stable
and not getting worse.
Leaflet Moorfields Epiretinal
The vision can be affected in various ways. Central vision can
be reduced, causing generally blurred vision. Alternatively, images
may appear bent or wavy.
If the sight does get worse and the wrinkling increase, then surgery
may be recommended. Only ~30% people notice an increase in the
wrinkling, and their sight will deteriorate over months or a year.
In this group of patients surgery improves sight in ~80%. Eye 2011. Photoreceptor damage JAMA 2013. Surgery is not recommended in 'mild' or 'early' membrane formation.
Causes of ERM
With a PVD, when the vitreous shrinks, it
may release cells from the surface of the retina. These cells
migrate and start to 'grow' on
the surface of the retina near the macula, and then start to shrink.
See ERM cause animation.
The condition occurs as people get older. We do not know the exact
cause, but various conditions stimulate growth factor release,
and these promote the growth of the membrane.
- It may be related to a PVD. This occurs
as the vitreous gel shrinks.
- it may be related to other conditions with retinal damage,
- retinal tear (1/30)
- retinal vein occlusion
- laser treatment
- types of ERM
This patient has had an ERM for 4 years. The vision was 6/9 and has deteriorated a tiny amount to 6/12, with a lttle distortion. The ERM is seen as wrinkling on the OCT (blue arrow below). The entire central retina is thicker than the opposite eye (OCT and photo just further below).
ERM..top scan and photo, blue arrow. The membrane is just visible on the photo (blue arrow). Other eye below, normal (minimal ERM). Patient age 68y, female, enlarge
an epriretinal membrane, a common cause of visual problems , enlarge
Surgery...vitrectomy and epiretinal membrane peel
The surgery starts by passing small
instruments through very small holes. Then the vitreous is removed.
(The vitreous is the jelly in the middle of the eye..this part
of the operation is called a 'vitrectomy').The membrane is then
peeled off and removed. animation.
The vitreous is replaced with clear fluid.
Such vitrectomy surgery for ERM may be helpful if there is distortion
of vision, or if the sight is worse than 6/12. Removing the ERM
will usually help reduce the distortion, but may not improve the
visual acuity. The more opaque the membrane, the more the benefit.
The best results are for patients whose sight is <6/18, and whose
sight has deteriorated in the last 6 months.
As with any operation there are risks. The main risks are complications
such as infection and retinal detachment, both of which can be
very serious and cause severe loss of sight.
The risk of such a
major problem is probably about 2% (1 in 50). Many patients will
develop a cataract, and there are a number of minor problems (and
rarely more serious problems) that can develop.