Because it looks more Jesus to have brown eye?
Look at the typical European depiction of Jesus in wikipedia, first picture of the page.
Also in the article:
In the 2004 movie, The Passion Of The Christ, Jesus was portrayed by James Caviezel who wore a prosthetic nose during filming and had his blue eyes digitally changed to brown to give him a Middle Eastern appearance. According to designer Miles Teves, who created the prosthesis: "Mel [Gibson] wanted to make the actor playing Jesus, James Caviezel, look more ethnically Middle Eastern, and it was decided that we could do it best by changing the shape of his nose.
http://en.wikipedia.org/wiki/Race_and_appearance_of_Jesus
Jesus's appearance can be whatever you like him to be because no one really know what he looks like. Some picture he is black and in some he is Asian.
May be if the movie is directed by Ang Lee targeted toward the Far East audience, Jesus will be Asian.
I believe he has grey coloured skin with large black eye and about 1 meter tall.