Chimerism really sounds like something formed out of a Nigerian name. Are you sure it wasn't discovered by some Igbo dude named Chimere or Chime:)
But seriously when one considers the things that could go wrong in the system of an organism, and how none of them goes wrong for a long long time, you just can't help be grateful for the blessings, seen and unseen.
Now, a question, do you think it is possible to isolate the cells with one type of DNA and gradually extract them from the body until it is only one set of DNA that is left? And if that is possible, what becomes of the blue eye in the case of the chimera cat? Does it gradually turn hazel or it just remains the same? Too many questions, I know.
If they had to fix chimerism, it would be implausible to do it after the organism is grown up. It would be implausible even if you froze time at the exact second of fetrilization and tried to fix it. It simply cannot be fixed using modern technology. But if it were fixed, the eye would slowly turn hazel. The pigment of the eye is similar to the pigment of the skin. So just how your skin gets lighter if you don't go in the sun for a few weeks, the eye would also change color over time (note that these processes would still be somewhat different because one is an environmental change and the other is a genetic change; I was just drawing an analogy).
The analogy could not be improved upon if one tried.
Those are hard questions, my friend and I'm not with my glasses :)
Well, I think this is a pretty new area and a lot of research still needs to be done on it. I doubt we shall ever be able to extract one set of DNA so the blue eye remains with the hazel!