I just discovered by accident the terminology for the unusual colouration of my eyes.
Central heterochromia is an eye condition in which there are two different colors in the same iris. Central heterochromia is where the central (pupillary) zone of the iris is a different color than the mid-peripheral (ciliary) zone.
Eye color is determined primarily by the concentration and distribution of melanin pigment within the iris tissues, anything affecting those factors may result in a difference of color being observed. Central heterochromia appears to be prevalent in irises containing low amounts of melanin.
Eyes displaying central heterochromia are often referred to as “cat eyes” because of the appearance of a multi-colored iris.
Text taken from the Wikipedia article Heterochromia and licensed under the Creative Commons Attribution Share-alike 3.0 license.