This is a membrane that forms on the surface of the retina. As this film contracts it can cause distortion of the retina. If vision is affected, it may need to be surgically removed by peeling it away from the retina.
What causes an epi-retinal membrane?
Most are caused by the vitreous (the jelly inside the eyeball) pulling away from the retina. It is most common in people over the age of 50. Other causes include inflammation inside the eye and certain types of eye surgery.
How does it affect the vision?
In the early stages, you may not be aware of any changes to your vision. However, if it starts contracting it can cause distortion of the central vision, like looking through a waterfall. Treatment is usually only necessary if you are aware of significant distortion in your vision which is interfering with everyday activities.
How is it treated?
First, the vitreous of the eyeball is removed during a 'vitrectomy' procedure. Then, the surgeon gently peels the epi-retinal membrane away from the retina.