National Different Colored Eyes Day Date in the current year: July 12, 2024

In a general sense, the term “heterochromia” refers to a variation in coloration of the eyes, hair, or skin. However, it most often used to denote heterochromia iridium (or heterochromia iridis) — different or partially different eye color that results from an uneven distribution of melanin.

There are two main types of heterochromia of the eye: complete and partial. Complete heterochromia is when one eye is a different color from the other, for example, blue and green, blue and hazel, or blue and brown. In partial heterochromia, the same iris contains two different colors that may be arranged in a sectoral manner (sectoral heterochromia) or in a concentric manner (central heterochromia).

Heterochromia is found both in humans and domesticated mammals (dog, cats, horses, cattle and even water buffalo) with some breeds being affected more frequently than others. Odd-eyed cats are often white or mostly white, although not necessarily. Most cases of heterochromia are genetic and do not affect vision. However, some cases of congenital heterochromia are associated with certain syndromes and diseases. Acquired heterochromia usually results from injury, inflammation, tumor, or the use of certain eye drops.

Famous people with complete or partial heterochromia include, for example, Kate Bosworth, Mila Kunis, Jane Seymour, Alice Eve, Olivia Wilde, Demi Moore, Dominic Sherwood, Henry Cavill, Benedict Cumberbatch, Robert Downey, Jr., Alyson Hannigan, Jonathan Rhys Meyers, Simon Pegg, Joe Pesci, Kiefer Sutherland, Christopher Walken, and many others. David Bowie is sometimes erroneously said to have had heterochromia, while in reality he had anisocoria, a condition where one pupil is larger than the other.

National Different Colored Eyes Day was created by Jeanne Quinn of B. Able Inc, who herself has heterochromia. She selected the date of July 12 simply because it is her birthday. Quinn created the observance to celebrate the uniqueness of people that manifests itself in many ways, including different eye color, as well as to raise awareness of heterochromia.

If you want to observe National Different Colored Eyes Day, you can do it by educating yourself about heterochromia and the challenges that people with this condition face. Although most cases of heterochromia are benign and don’t affect eyesight unless heterochromia is caused by an underlying condition, people with heterochromia might get fetishized, which is not a great thing to experience. So you should be careful when complimenting someone with different colored eyes.

If you (or your pet!) have heterochromia, use National Different Colored Eyes Day as an opportunity to celebrate your uniqueness and share your story and photos with the world using the hashtag #DifferentColoredEyesDay. Maybe it will help someone understand heterochromia better.