3 types of heterochromia: complete, central and sectoral

In sectoral heterochromia, sometimes referred to as partial heterochromia, areas of the same iris contain two completely different colors.

Central heterochromia is an eye condition where there are two colors in the same iris; the central (pupillary) zone of the iris is a different color than the mid-peripheral (ciliary) zone, with the true iris color being the outer color.

The one of interest to me is central heterochromia due to high frequencies observed among Rh negative individuals.