Why does your eye move rapidly during REM sleep?

Ummmm, anyone got an answer to this. I just can't see the logic to why your eye would have to move really fast when you are sleeping?

Here's a good link:
http://web.sfn.org/content/Publications/Br.../rem_sleep.html

Thanks for the link but I couldn't see where the answer to the eye-moving question was. All I read was that the mind was active during REM sleep not why the eye moves so much.

Thanks for the rapid replys

Some say it is your eyes following things in your dreams, so if you look around in your dreams your eyes move in the real world, they are not paralyzed then i gues

The paralyzation neuro transmitters that the brain releases in sleep don't have any effect on the eyes, so you get rapid movement in sleep, and research says that the eyes are actually following your dream eyes...