Blind With Purpose

My favorite scene in Denzel Washington's movie The Book of Eli is when we get a close look at his eyes. He appears to be blind and this information compels a re-thinking of all the previous scenes. A blind man with purpose goes farther and straighter and more effectively than sighted men without purpose. But how can this be?  The Book of Eli is like a Christian version of the Zatoishi series. The big difference is purpose. Denzel is deadly because he has one. Zatoishi is deadly even without one.