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, which is 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 membrane.
30% of ERM patients do later need surgery Eye19.
The vision can be affected in various ways.
- Central vision can be reduced, causing generally blurred vision.
- Alternatively, images may appear bent or wavy. Distorted vision: the distortion is related to the retinal pulling Eye 2013.
- symptos: metamorphopsia EN 19
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. Surgery is not recommended in 'mild' or 'early' membrane formation.
Photoreceptor damage JAMA 2013.
See ERM cause animation.
When the vitreous shrinks (posterior vitreous detachment (a PVD), 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 the retina 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 other conditions with retinal damage, including Retina 2011 Yazici, retinal tear (1/30), retinal vein occlusion, laser treatment
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 little 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 OCT and photo, blue arrow. The membrane is just visible on the photo (blue arrow). Other eye bottom OCT, normal (minimal ERM). Patient age 68y, female, enlarge
an epiretinal membrane, a common cause of visual problems , enlarge
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.
Early surgery may help Eye 14. Surgery may be considered if
- sight is 6/12 or worse, and the poor sight is due to the ERM, not for example, cataract or ARMD
- the patient is disturbed by the poor sight or distortion in vision
- the ERM is not very long-standing
- the patient is well enough to undergo a ~1 hour operation with local anaesthetic and lie still
- patient accepts there is about 1/100 risk of a serious complication such as needing a second operation or infection
- a high risk of increased cataract formation
- younger patients benefit from earlier surgery. Retina 19