- What is it?
- Who gets it?
- What are the symptoms?
- How is it treated?
- What does the surgery involve?
- How successful is the surgery?
What is it?
The top image shows a retina with a fine "epiretinal membrane" growing on the surface. As a result, the normal architecture of the retina is distorted, and the resultant vision is likely to be reduced and distorted. The image below that shows a normal appearing retina for comparison.
Epiretinal membrane describes the formation of a fine membrane that grows on the surface of the retina. The retina is analogous to the film in the back of a camera, and normal architecture of the retina is essential for good vision. The problem with an epiretinal membrane (also known as macular pucker or cellophane maculopathy) is that it distorts and contorts this retinal structure so that the vision becomes reduced and distorted. In the majority of individuals with epiretinal membrane, no cause is identified. Occasionally the cause relates to a retinal tear, or previous surgery, ocular inflammatory disease, a retinal vascular disease or previous laser treatment / cryotherapy treatment for an old retinal tear.
Who Gets It?
The majority of patients with epiretinal membrane are aged over 50 years old. As we continue to age, the incidence continues to rise, and it has been estimated that up to 20% of all people aged over 75 years have some degree of epiretinal membrane (though the vast majority will be visually not significant).
What are the Symptoms?
For the majority of patients with an epiretinal membrane, the patient doesn't have any symptoms and for these patients, no surgery is recommended. Surgery should only be considered for those patients that have noticed a visual problem. When patients do have symptoms, the majority describe onset of distortion with blurred vision. Occasionally, objects in the eye that has the epiretinal membrane appear bigger than objects in the other eye (so called macropsia).
How is it Treated?
As mentioned above, for the patients who do not have any significant visual symptoms, no surgery is recommended as surgery will not result in an improvement in their quality of life. Only 10-20% of patients with an early symptom-free epiretinal membrane go on to develop symptoms over a two-year follow-up period. For those that do have symptoms, a choice is usually made between observation only (if the patient is managing reasonably well at present), or surgery (if the epiretinal membrane is having such a significant effect on their vision that it is beginning to effect their vision related quality of life.
What does the surgery involve?
Surgery for epiretinal membrane involves mechanically peeling away the membrane from the surface of the retina. In order to gain access to the membrane, the vitreous part of the eye (the gel that fills the cavity at the back of the eye) is removed (a so-called vitrectomy). The vitrectomy is performed using three "keyhole" incisions in the eye. After removal of the vitreous gel, the epiretinal membrane is peeled off the retina using microforceps. Finally, the peripheral retina is searched for any retinal tears. If retinal tear(s) are found in the periphery (usually in about 5% of cases), they are treated (with laser or cryotherapy), and a gas bubble is placed in the eye. Otherwise, no gas bubble is placed in the eye. The surgery can be done under local anaesthetic (where the patient is awake) or general anaesthetic (where the patient is asleep). The surgery usually takes approximately one hour to perform. If there is a signifcant cataract in the same eye as the epiretinal membrane, this can be removed at the same time.
How successful is the surgery?
For the vast majority of individuals (80 to 90%) undergoing epiretinal membrane removal, they notice an improvement in their symptoms of distortion and improved vision, but it may take up to three to six months for this improvement to be noticed. It is important to remember that up to 5% of epiretinal membranes can recur and come back, sometimes necessitating further surgery (though the majority of recurrent membranes are visually insiginificant).