i had the same thing going for quite a long time... every time i would center myself and be in a meditative state the lights would react.
now since some months it appears to have stopped.
one thing i remember hearing about it was that it means you don't have perfect control of your energies, and that some "goes havoc" and gets intermingled with the emfs around you... this made sense to me...
i now think this kind of phenomenon is pretty common among people doing meditation or psychic stuff..