We are featuring those unique dogs that have different coloured eyes today on our social media! Did you know the official name for this is Heterochromia, which is caused by a lack of the pigment melanin in all or part of one eye. In dogs with heterochromia, the lack of melanin causes one of their eyes to appear blue or bluish-white. Heterochromia in dogs is often hereditary, meaning it is passed through their genetic makeup.