Return to Education Topics

 

Retina Topics

 

Epiretinal Membrane

Posterior Vitreous DetachmentThe eye is a hollow spherical structure. Internally, a delicate sheet of nerve tissue called the retina lines the wall of the eye like wallpaper. The central cavity of the eye is filled with a sticky gel called the vitreous. Over time, the vitreous gel tends to liquefy in its center, creating liquid pockets surrounded by the more formed gel. Eventually, with enough degeneration within the vitreous gel, the filamentous scaffold collapses and the vitreous separates from the retina. This event is called a posterior vitreous detachment (PVD).

When the vitreous pulls on the retina - to which it is attached - the photoreceptors are mechanically stimulated. As the gel pulls away, it may irritate the retinal surface and cause a thin film of scar tissue to proliferate over the irritated area. This usually happens right in the macular area, and may distort or blur the vision.

OCT Scanner
OCT Scanner
Normal Macula OCT
Normal OCT Scan of the Macula
Epiretinal Membrane
Epiretinal Membrane distorts the retina

This condition is common in the age group undergoing cataract surgery, and when it is present it may result in less vision improvement after surgery than the doctor and patient expected. At MarinEyes we try very hard to identify this condition BEFORE the cataract surgery in order to counsel the patient correctly. It can be very difficult, however, to see the epiretinal membrane when it is obscured behind a cataract.

When the condition is suspected, confirmatory testin wioth "OCT" is simple and painless, as part of a dilated examination. To the right, the smooth contour of the normal retina contrasts with the wrinkled retina in the bottom image. If you look closely, you can see the thin line representin the epiretinal membrane stretched over the wrinkled retinal surface.

There is a surgery to remove this scar tissue if the distortion is bad enough to warrant the risks of failure to improve the vision, retinal detachment (5%) and cataract (100%) following the "Vitrectomy with Epiretinal Membrane Removal." This surgery is generally done in hospital outpatient departments by retinal subspecialists.