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National Different Colored Eyes Day arrives every July 12 to celebrate heterochromia iridum, the fascinating genetic variation that gives an individual two distinct eye colors. This rare and often admired trait is found in only about 1% of the population. Take a moment to appreciate the unique beauty of different colored eyes and learn more about this captivating phenomenon. Share your own stories or admire those who carry this special pigmentation!
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History of National Different Colored Eyes Day
While today, people with two different-colored eyes are likely to get a compliment, that was far from the case through history. For example, Native American Indians used to believe that those born with the unique coloring could see both heaven and earth through their “ghost eyes.” Because they had seen dogs born with the trait, they found it inhuman and ghostly.
Many myths and fears have long been associated with heterochromia iridum, including superstitious beliefs that those with the trait were witches, were evil, could see beyond their own deaths and into the afterlife, or could consort with ghosts and spirits. Since eyes are the windows to the soul, ancient peoples who couldn’t explain the abnormality quickly resorted to ghostly explanations that painted the trait as making someone less-than-human.
Today, of course, our society finds it beautiful! However, it’s not widely understood. Did you know it can either appear at birth or be acquired? Especially if it’s acquired, it’s recommended to see a doctor just to ensure the condition is benign. While the vast majority of cases are completely harmless and simply pretty, some can indicate eye damage or that there is another underlying disease. Better safe than sorry!
There are actually three different kinds of heterochromia iridum – complete, segmental, and central. Central, the most common, appears as matching irises with different colors encircling the pupils. Many don’t know this classifies as heterochromia iridum! Segmental heterochromia appears as a different patch of color in only one iris, and complete heterochromia is the most iconic – two irises of different colors.
Whether genetic or not, the total percentage of the population with the trait is less than one half of one percent. If you want to know if there’s a chance it’s in your genes, comb through some old family photos! Keep in mind it can be very hard to discern – the majority of people actually don’t notice the condition in someone else, and it can be very easily mistaken.
National Different Colored Eyes Day timeline
It was around this age when humans, who had up until this point only had brown eyes, started to display a genetic mutation allowing for different eye pigments!
The credit for discovering heterochromia is often given to Aristotle, who named it “heteregloucos.”
Though Islamic scientists were studying eyes as early as the 10th century, Italian transformed knowledge of the human eye in the 15th century with a new understanding of the physical form of the eye.
The first hospital dedicated to the practice of ophthalmic was established in London.
This Ophthalmoscope was created to inspect the retina, has led to new understanding and new subspecialties in the optometry field since it became widely known.
National Different Colored Eyes Day FAQs
When is National Different Colored Eyes Day?
National Different Colored Eyes Day 2026 falls on Sunday, July 12, offering a perfect weekend opportunity to learn about and appreciate this unique genetic trait.
How common is heterochromia?
Heterochromia iridum, the condition of having different colored eyes, is quite rare in humans, affecting less than 1% of the global population. This makes it a truly distinctive characteristic.
What causes different colored eyes?
The primary cause of heterochromia is a variation in melanin concentration within the iris. Most cases are congenital (present from birth) and benign, often inherited as a genetic trait. It can also be acquired later in life due to injury, disease, or certain medications.
Are there different types of heterochromia?
Yes, there are three main types: complete heterochromia (each eye is a completely different color), sectoral heterochromia (only a segment of one iris is a different color), and central heterochromia (the inner ring of the iris is a different color from the outer ring).
How to Celebrate National Different Colored Eyes Day
Learn more about heterochromia
Heterochromia iridis comes in many forms, and in many species. Spend a few minutes looking it up today and learning more about what makes these lucky individuals so special!
Post it up
If you’re one of the lucky few who can wield the captivating gaze of two differently-pigmented eyes, share your best selfie on a social media platform with a hashtag. While having two differently-colored eyes is indisputably stunning, sometimes accepting things that make us different can be challenging - someone else with heterochromia may feel inspired or confident just from your selfie.
Shout out a friend or celebrity with heterochromia
If you have a unique friend with two different colored eyes, give their selfie and like or comment to boost it! If you don’t, go give some love to a celebrity with the condition - choose from Kate Bosworth, Jane Seymour, Dan Aykroyd, Henry Cavill, Mila Kunis, Josh Henderson, and more!
5 Fun Facts About Different Colored Eyes
Heterochromia is usually benign
Translation: having different colored eyes is almost never an eye disease, and almost never will affect your vision.
Stars - they have heterochromia just like us!
Dan Aykroyd, Mila Kunis, Henry Cavill, and more all have heterochromia.
Man’s best friend
The breeds of dogs that most often have heterochromia are Siberian huskies, Australian shepherds, collies, corgis, and Chihuahuas.
Born to be odd
Some animals like “odd-eyed cats” are bred specifically to have this genetic feature!
Heterochromia mistaken for anisocoria
Anisocoria, which is when a person has two different pupil sizes, can sometimes be mistaken for having two different colored irises - take David Bowie for example!
Why We Love National Different Colored Eyes Day
t’s a celebration of diversity
Part of what makes heterochromia iridum so striking is that it’s so rare! Human beings come from all walks of life and no one has exactly the same coloring. The more we can celebrate the little things that make others unique, the more we can accept the differences we have ourselves.
It’s striking and captivating
The gaze from a person with two different colored eyes is stunning! It’s a look that no one is soon to forget, and it’s obviously envious - people often buy colored contacts just to mimic the natural look. If you’re one of the lucky few with different colored eyes, take a second to appreciate it today!
It’s artistically inspiring!
Many pieces of art center on people with different colored eyes, as the striking gaze is so unique and inspiring. Makeup art also has made heterochromia iridum a trend that is accessible to any artist with colored contacts and a flair for the dramatic.
