They say your eyes are the windows to your soul. If that's the case, Riddick's soul must be very peculiar. His eyes show luminous colors that seem to change when seen from different angles. Sometimes they are dark, cloudy, and mysterious. Other times they are bright and confident. The colors change unexpectedly, and no one can ever predict which Riddick is behind them. All one knows is that he would not be the same man if he didn't have them. They make him the mysterious, confident, and unreliable animal that he is.
His kaleidoscope eyes let him see the most mysterious places of all: the dark shadows. In the black secrets can lurk, and only he can uncover them. His goggles hide his gaze, so no one knows for sure where he is looking.
His confidence comes from being able to truly see people. He is so observant, he can see details and make conclusions about someone without ever giving away that he knows. Riddick can escape the toughest situations that hundreds of men have tried, and failed, to because he envisions the obstacles in his path. He can always calculate the best route for survival.
Riddick can be the sole person capable of saving your life, and yet, he might choose to leave you to die. He is very unreliable. Survival of the fittest -his self- is all that matters. Love doesn't always trump instinct. Some try to guess his actions, but even he doesn't know what he is going to do most f the time. One's eyes give away their intent, and his eyes are always covered.
Riddick transfers this unstableness to his prey. His eyes can hypnotize and command them. Those whom he has just killed appreciate this fact. One can see it in their surprise right before they take their last breathe; see it in their awe at the fact that they, indeed, are dying; see it when they choose to have his shimmering eyes be the last image they see on Earth. They ask themselves, "Could something that beautiful really be so destructive?"