Retina specialist arranged an electroretinography (EGR) at a local university. He's trying to find why I have movement and a flame like flashing in the bad eye. He is aware of my filtration surgery of June, 2008. When my case was reviewed by the ERG technician, she asked her supervisors about the risk of ERG due to the filtration device. They told her to suspend the tests. The eye surgeon who did the filtration was not available, and his colleague would not venture an opinion. Tests stopped, until the implant company, and my eye surgeon could be reached. Has Dr. Hagan or other MD's who respond here had any experience with ERG and filtration devices for glaucoma? Is the test safe to do? Russell903