It seems that is a very good question. The first person I saw that did the initial exam had no earthly idea and never heard of it before. The next person I saw that dilated my eyes actually asked me what happened. Then I saw Dr. Katzen. He knew.
He said most babies are born with blue eyes and over time they change as pigment develops over the blue. For some reason the pigment in my eyes wore away (most of it, he still saw a bit of it in there) and the original blue was able to be seen again.
Also there is now under development a medication to do just this, it's not ready yet. There seem to be a lot of people that want natural blue eyes. Lucky me.
On another note my eyes are still great. There is the very slightest sign of early cataracts but not hurting my vision at all yet. Nothing else wrong. Great vision. No glasses needed for anything but reading and drug store readers are fine. He is a fabulous eye doctor, Sarge always used him.
But there was some poor planning on my part. I never thought about my eyes being dilated. That meant I could not get in the pool because the sun was too bright. Sooooo, I had a lovely nap instead. The end.