they are a involuntary reaction, usually assosated with large consumptions of caffine, starting at things with high light varations a.k.a video games with lots of flashing, or staying awake for really long periods of time... so get some sleep stay away from caffine and tv/ computer for about a day and it should go away, i had a friend like that, they said it could turn into seziures (sp) if you leave it go for like months, (moms a nurse) but dont quote me on that if it doesn't go away in a few days call a doctor