It is most often soft colors (Green, blue, purple) and usually more like out-lines than anything, but they glow (not very brightly), almost
neon-like. If I am really focused on something, eventually it starts double imaging in a similar fashion, and this double image will just drift off.
They are much more prominent around the edges of my eye, and if I strain my eyes (reading in the dark, staring for a long time, and moving my eyes to the end of their motion).