How to take a very detailed picture of my eye?

I would really like to try to do something like this but for some reason, my camera won't focus on my eye at all. I'm using a Nikon D40x with a 55-200mm lens. Instead of using my manual setting, I set it to macro but my camera still won't focus on my eye. Do I need to get a macro lens or do I just need brighter lighting?

Your best bet is to have a macro lens and have someone else take the photo - it's going to be next to impossible to get the shot framed and focused on your own eye, as you obviously can't look through the viewfinder to focus and compose the shot yourself.

You may need extension tubes to get that close. Http://www.samys.com/cart?quantity=1&ACTION%28buyBoth%29.x=102&ACTION%28buyBoth%29.y=22&ACTION%28buyBoth%29=Add+To+Cart&pid=5421&infoID=KENKAEXTUBEDGN&categoryType=1&action=buyBoth

You can buy one or more or a set.

I know Canon has a software program that will control the camera through the computer - I've heard Nikon has similar, but I don't know where or what. That could solve the viewfinder problem but you'll still need the right lens.

Macro mode is not enough. You need a macro lens.