Some dogs have striking, differently colored irises. Heterochromia is a herediatry condition that comes in three flavors: 1. Heterochromia iridis, or bi-eye, where each complete iris is a different color from the other. 2. Sectoral heterochromia, or parti-eye, where the same iris contains at least two colors and is split, flecked, or marbled. 3. Central heterochromia where the color surrounding the pupil flares out irregularly from the center. Interestingly the same genes responsible for heterochromia, produce merle and piebald coats.