What is an epiretinal membrane (ERM)?
It is an extra, abnormal layer of fibrous or scar tissue which proliferates on the surface of the retina. In clinical practice, we usually are only concerned with macular epiretinal membranes, as the macula is the most important part of your retina – the part responsible for your central vision.
What problems does it cause?
In many patients, early membranes cause no symptoms or problems and do not need treatment. In some patients, the membranes can contract, causing the retina to become thickened and distorted. This can cause any of the following symptoms:
- blurring
- distortion – straight lines eg door frames do not appear straight
- double vision or ghosting of images
- macropsia – everything looks larger with the affected eye
Can epiretinal membrane spontaneously resolve or fall away from the retina?
Yes, but it is so rare that this eventuality need not be considered for practical purposes.
How can epiretinal membrane be treated?
The only treatment is to surgically remove the membrane in an operation known as a vitrectomy. Below are some images of Mr Shah performing surgery for epiretinal membrane.
A: the macular epiretinal membrane is difficult to see prior to staining
B: To aid visualisation, the epiretinal membrane is stained with a blue dye containing Brilliant Blue and Trypan Blue
C: Under high magnification, the ERM can now be seen causing striations on the retinal surface
D: Mr Shah delicately removes the ERM with highly specialised membrane forceps.
I have cataract as well as epiretinal membrane – can both be treated at the same time?
Yes – this is called combined phacovitrectomy and is a commonly performed procedure. If you have significant epiretinal membrane and you opt for cataract surgery alone, then the ERM is known to be associated with a higher chance of retinal swelling after the cataract operation. However, the combined procedure is a bigger operation to have than the cataract operation alone. This is quite a difficult topic to discuss generically – in reality most patients will have individual factors, some specific to their ERM, which may make either option (cataract extraction alone or cataract extraction combined with vitrectomy and ERM removal) the more sensible choice. This is a discussion to have with your vitreoretinal surgeon.
