HETEROCHROMIA is an alteration in iris color and structure. Although usually benign, it may be the only clue to an underlying disorder. The purpose of this report is to discuss the development and significance of this finding and to emphasize the importance of recording it.
Aristotle described the condition and called it heteroglaucos. The history books also record that the eastern Emperor Anastasios I was called Dicorus because his eyes were of different colors, and Plutarch states that Alexander the Great had heterochromia.1Heterochromia may take two forms: a hypopigmentation of the iris of whatever color, with iris hypoplasia; or a hyperpigmentation, with iris hyperplasia. The color change may involve one eye alone or both eyes and may be partial or complete. The uniocular type in which different parts of the same iris are of different colors is called heterochromia iridis, piebald iris, variegated iris, or iris
Richard M. Gladstone. Development and Significance of Heterochromia of the Iris. Arch Neurol. 1969;21(2):184–192. doi:10.1001/archneur.1969.00480140084008