http://vector.tutsplus.com/tutorials/illustration/how-to-draw-and-color-anime-styled-eyes-in-adobe-photoshop/

One of the most striking things about any portrait are the eyes. So it’s with this tutorial, I’m going to guide you through the process of drawing and coloring anime-styled eyes with vector tools in Adobe Photoshop. If you’re an intermediate to advanced user of Adobe Illustrator or any other vector program, you should be able to translate this tutorial to your preferred program.