Creating a realistic eyeball?

Just wondering what some techiques to creating a realistic eyeball would be?

Currently, I’m using catmul-clark subsurf on a an 8X8 UV sphere.

maybe this might help?

http://web.pdx.edu/~wlf/tut.html

EDIT: and maybe this too:

http://www.kandsdesign.com/kim/eyemap-tut.html