An epiretinal membrane is a thin almost transparent membrane growing over the top of your retina (see retina above). This can cause wrinkling and distortion of the retina, resulting in distorted vision. WE perform a detailed high magnification scan of the retina of all patients presenting with cataract called an OCT. This will usually show if you have an ERM is present or not. An ERM does not mean cataract surgery would not improve your vision. However when the ERM is quite bad, it can be treated at the same time as the cataract surgery. When an ERM is present and cataract surgery is performed, the chances of developing CME (see above) is greater than if you did not have an ERM.