I am a daily PC user. As most users, I have a taskbar (using Windows) that shows icons of programs. My two screens are big (24") and I'm at ~60cm distance from them, so fairly often I need to turn my head. What I notice is.. that if I turn my head, but look with my eyes at the icon taskbar (or even keep looking) one specific icon is moving with the movement of my head. When I turn my head left the letter on the icon moves left too, like this (3x original size):
Other icons don't seem to move (they have no letters).
But in reality - it does not move (too, like the other icons).
I'm using negative glasses (-4.5).
Why does this happen? It doesn't happen when I don't have my glasses on.