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
The pigment is there for a reason --- presumably UV protection --- I would watch out for cataracts and/or other eye damage.
Wear GOOD UV glasses 24/7.