I just did something yesterday something that dramatically augmented the effect (not on purpose.) I was walking through the house (towards a big bright window) bent down to pick up something off the floor, stayed down about 10 secs., and when I came up (directly in front of the window) About a gazillion of those little light thingies came up in front of my eyes, almost preventing me from seeing. (imagine so many sparklies you can't hardly see). They quickly dissipated leaving the usual amount. To me this shows this is a physical characteristic of the eye. What it is specifically, IDK.