If you stare at a sharp black-and-white pattern for an extended picture of time, then stare at a blank wall, you will see the "negative" of the pattern you were originally staring at.

Green seems to be the "negative" of pink. When you stare at the center of the circle for a while, then look at another part of the screen, you will see a circle of green dots - this is the negative image of the pink dots.

When a pink dot turns off, you will see its negative image (green) shortly afterwards. As the pink dots sequentially turn off and on around the circle, you therefore see a green dot circulating.

I have no explanation for the pink dots disappearing ... maybe it is Visine ...