Tiger claw technique... like he was trying to pluck out California Mountain Snake's eye. Holy shit, California Mountain-- coincidence?
Eye poking, open-palm strikes, swiping, and leaving your fingers out like that are all illegal. St-Pierre was examined after the fight for a possible detached retina but just had blood in the eye and swelling.
I don't believe it is an official rule but referees usually warn fighters to keep their hands clinched when kickboxing, simply to avoid the open-finger glove problem that is pokes, scrapes, and gouging. Open-palm strikes like chops and slaps are useless in MMA, especially with gloves on.