I was really bored one day. So I decided to take a picture of my eye (for a facebook picture). Alas, the only camera I had was, well, a poor quality webcam. (I will keep its identity a secret to save embarrassment.) Anyways, here's the required materials.
-small white led light source
-eyes (yeah, you probably figured that one out already, too.)
Step 1: Light Source
So, the problem with most webcams is that they just don't pick up light too well. Your eyes are recessed into a cavity in your head which makes a shade from the sun. A fix for that problem, without having to dremel your brow down, is to get a good light source that can get back there and give the webcam some help. I used one of those little two dollar flashlight/laser combos from wal-mart. You can use a different light source, of course, but you'll need something that has a bright white light (say that 3 times fast), preferably LED.
Step 2: How to Illuminate Your Eye Without Blinding Yourself.
As shown in the picture, place the camera's x rotation (that's from the front) at a 45 degree angle to the eye and it's y rotation parallel to the eye. This will illuminate your iris and pupil and not make you blind.
Step 3: Take the Shot, and You're Done.
Okay, so now that you're set up, have somebody click the "take picture" button for you, so you can look directly into the lens of the camera. This is crucial, because it gives the best illumination possible and the most detail possible without perspective messing the shot up. There you go, a decent quality picture of your eye with at not-so-decent webcam.