Some times i will be sitting there and all of a sudden i start to experience tunnel vision with these images just popping up in my Peripherals. I cant make out what they are because there are more than one at a time, very small and each one only last about 2-3 secs and than another replaces that image. After a few seconds the images start coming faster and faster and the tunnel vision gets worse, than it just stops after about 2 minutes.