For whatever reason I have always loved the look of high contrast art where the grey tones are essentially eliminated and all you are left with are the main features. I think a lot of this comes from the fact that I love art that deals with light as its main driver for the look and feel of a piece. Generally a very strong light will create a high contrast as the strong highlights push the grey tones out of the way.
I did this piece a while ago but I wanted to move it over to my art account where it belongs.

Here is an eye tutorial I made using this piece for anyone interested.