Through my years of seeing patients, I have come across many patients that have developed an epiretinal membrane. Without fail, almost all of them will express that they have never heard of an epiretinal membrane and are quite perplexed as to what it is, why they have it and what exactly is happening inside the eye. Hence, I realised the need to write this simple explanatory article about all you need to know about epiretinal membranes.

What is an epiretinal membrane?

Epiretinal membranes happen more common than most of us realise. Although many of us have never even heard of this condition, it actually occurs in 10-15 % of our population with at least 1 affected eye, with 30% occurring in both eyes. It is an abnormal layer of fibrous (white and sticky) tissue that grows on the surface of the retina. I like to tell my patients to imagine it’s like a piece of adhesive tape (hence the name Cellophane Maculopathy) inside the eye that sticks to the top of the retina and causes the retina to become wrinkled and swollen.

(above – normal retina)
(above – retina that developed an epiretinal membrane)
(above – another example of wrinkled retina due to epiretinal membrane)

Because it tends to occur at the central part of our retina, the macula, it frequently causes symptoms such as blurring of central vision which could lead to straight lines appearing as wavy lines. That is why it is also known as ‘macular pucker’. The change in central vision in the affected eye arising from macular pucker usually starts out mild, but may worsen over time.

Who gets it?

Actually, anyone could develop an epiretinal membrane. Factors that put us at higher risk are:

  • Increasing age & macular degeneration
  • High myopia
  • Previous eye surgeries or eye lasers
  • Other eye diseases such as retinal tears, diabetic retinopathy, myopic degeneration, internal eye inflammation etc..

Why is it important to detect epiretinal membrane early?

Because the membrane tends to contract and brings about swelling and damage to the macular cells over time, we fear that if it is left untreated for too long, the vision may not recover well even after treatment.

Do all of them need to be treated?

I always tell my patients that the most important consideration is to first find out what the cause of the membrane is. The formation of the abnormal membrane could arise from, occasionally, a result of retinal detachment or eye trauma. I always do a detailed check of the entire retina looking for any signs of treatable retinal or vitreous disease and try to deal with that issue first.

By detailed – I mean it should include ultra-wide field retinal imaging, microscopic OCT retinal imaging and direct, meticulous visualization by a retinal specialist.

Then I assess the severity of the membrane by looking at firstly, patient’s symptoms and changes in vision. Secondly, the retinal characteristics including retinal architecture and macular thickness.

Epiretinal membranes which are causing little to no symptoms in vision can be left to close monitoring with a possible decision to intervene when it starts to worsen.

Only epiretinal membranes which are severe enough to cause a drop in vision or metamorphosia (wavy vision) will benefit from epiretinal membrane surgery treatment.

How are they treated?

Epiretinal membranes are treated surgically because it is necessary to physically remove the sticky material on the retina inside the eye. This is done via a procedure called ‘vitrectomy and membrane peeling’ which only a retinal specialist can perform.

This is a relatively simple day surgery where patients need not be hospitalised overnight. The procedure is done within an hour with the patient under full sedation which means it’s very comfortable for the patient.

Usually, if there is a cataract present in the affected eye, the cataract can be removed during the same procedure so that saves the patient the need for a second surgery.

Likewise, patients who are undergoing cataract surgery should have their eye(s) assessed for the presence of epiretinal membrane so the latter may be removed in the same setting.

Unfortunately, it’s been far too often that I have seen patients who had their cataracts removed elsewhere but never recovered good vision due to the presence of an epiretinal membrane that was not detected earlier. The membrane would then have to be removed in a second surgery. However, I always prefer to save my patients the trouble and cost of 2 separate surgeries, hence I like to plan for them to be done concomitantly where possible.

What is the success rate of epiretinal membrane surgery?

Under experienced hands, the membrane surgery success rate is very high – around 85-95%. There is always a small risk of recurrence, which means the epiretinal membrane may grow back after several years. The recurrence rate is quoted as 5-10%.

Already 1 week after surgery, the retinal architecture can start to recover back to almost normal. Visual recovery follows closely and improvements can be seen within a month, with potential to improve even further up to 6-12months after surgery. In fact, visual recovery can be rather remarkable after surgery.

(above – post-surgery 1 week epiretinal membrane)
(above – post-surgery 1 month epiretinal membrane)

However, the longer the retina was left damaged by the epiretinal membrane, the longer it will take for visual recovery and also the less likely it will recover fully. That is why I always encourage patients who are affected by their epiretinal membranes not to wait too long for their treatment.

I know it’s never easy to commit to any surgery. I do tell my patients that since the success rate of this surgery is high, it could be that this sight-saving surgery will restore your sight. When you think of it this way, you may be able to see that the benefits outweigh the risks.

References:

  1. Folk JC et al. Idiopathic Epiretinal Membrane and Vitreomacular Traction Preferred Practice Pattern(®) Guidelines. Ophthalmology.  2016; 123(1):P152-81.
  2. Cheung N et al. Prevalence and risk factors for epiretinal membrane: the Singapore Epidemiology of Eye Disease study. British Journal of Ophthalmology 2017;101:371-376.
  3. Yang Y et al. (2018) Ten-year cumulative incidence of epiretinal membranes assessed on fundus photographs. The Beijing Eye Study 2001/2011. PLoS ONE 13(4): e0195768.
  4. Geerts L, Pertile G, van de Sompel W, Moreels T, Claes C. Vitrectomy for epiretinal membranes: visual outcome and prognostic criteria. Bull Soc Belge Ophtalmol. 2004;(293):7–15.
  5. Dawson SR, Shunmugam M, Williamson TH. Visual acuity outcomes following surgery for idiopathic epiretinal membrane: an analysis of data from 2001 to 2011. Eye Lond Engl. 2014;28(2):219–224.
  6. Matsuoka Y, Tanito M, Takai Y, Koyama Y, Nonoyama S, Ohira A. Visual function and vision-related quality of life after vitrectomy for epiretinal membranes: a 12-month follow-up study. Invest Ophthalmol Vis Sci. 2012;53(6):3054–3058. doi:10.1167/iovs.11-9153.
  7. Donati G. Complications of surgery for epiretinal membranes. Graefes Arch Clin Exp Ophthalmol. 1998 Oct;236(10):739-46.