In seriousness, actual yellow iris is a near complete lack of pigment, so only the lipofuscin (a fat-like substance) is showing.
People with green eyes have this, but also have melanin.
To greatly over-simplify, a type of iris albinos.
That's interesting. Seems like some albinos have red eyes. There's another iris color that is very attractive, which is the very light blue some Russian women have.
Interesting, I didn't know that. My mother, myself, and my sister's youngest boy all have blue-gray eyes with a yellow ring around the pupil. I never realized that the famous familial ring was actually a lack of pigment!
As I've gotten older mine has gone from a defined ring to more of a bunch of splotches but the yellow color remains.
LQ