In a world that prefers shoes, handbags and even breast implants to match, a medical condition that disrupts the symmetry of someone’s face could be the world’s sexiest abnormality.

It’s called heterochromia and people with it have different-coloured eyes. It’s not a strange-sounding illness, however. It’s more of a beautiful mutation.

In Japan, it’s celebrated as a fetish and often depicted in Japanese anime. But its most attractive impact is found in real life. Cats and dogs display some dramatic occurrences of heterochromia that give even the plainest moggy a fashionable edge. It also adds an intriguing dynamic to the eyes of these famous faces.

Actors Kate Bosworth and Christopher Walken have the same heterochromatic pattern – one blue eye and the other is blue/hazel. Some other famous heterochromatic eyes belong to Elizabeth Berkley, Robert Downey Jr, Jonathan Rhys Meyers, Olivia Wilde, Alyson Hannigan, Joe Pesci and the latest Superman actor Henry Cavill.

Actor Kate Bosworth. Photo: Getty

When Kiefer Sutherland was dating Julia Roberts, she mentioned his mismatched blue-green eyes in an award acceptance speech.

The Lord of the Dance Michael Flatley has one green and one blue eye. Both Jane Seymour and Dan Ackroyd have a blue and a hazel eye. And comedic filmmaker Simon Pegg has eyes that are a mashed blue-grey peppered with brown bits. He refers to it as, ‘slightly mutanty’, something the characters in the following video can identify with.

But … what is it?

The simple medical definition of heterochromia iridis is when the iris of one eye is a different colour to the other iris.

Heterochromia acquired through disease such as tuberculosis or injury can have serious health consequences. It’s been associated with Waadenburg Syndrome which causes hearing loss as well as changes to hair and skin colour. Pigmentary glaucoma and melanoma of the iris are not to be confused with heterochromia. Both can symptomatically cause eye colour to change and require serious medical attention.

The other kind – congenital or hereditary heterochromia – occurs in approximately six out of 1000 people and rarely produces any medical issues or visual complaints. Instead, these people have an accidentally attractive facial feature that fascinates others.

But personal experiences do vary according to sites devoted to the condition. Here are some of the responses to it:

Reactions to having heterochromia

I love having it! “My right eye is dark brown and my left eye is pale blue. I love having two different coloured eyes.  My whole life people have found it interesting and asked me about it. Two of my sons also have it.” Clouisejones – female

Annoyed “What I don’t like about it is when someone asks me to describe my eye color (like on a drivers license or something) I have to pick one of the following that they [on the] list. I have full Heterochromia, one eye is hazel and the other is blue. I can’t pick blue or hazel alone because I would be lying.” Athru – male

Concerned “Would you date a guy with Heterochromia? Sexy or creepy? I’ve become very self-conscious about it. My right eye is black and my left one is blue. People think I’m a freak and I get made fun of! My last girlfriend thought there was something wrong with me. :(” Unknown

Hopefully, he got a confidence boost from the small avalanche of responses from women stating an emphatic ‘yes’.

Athletes and coaches who boast the condition include professional ice hockey players Shawn Horcoff and Ilya Kovalchuk, mixed martial artist Jens Pulver as well as pro-baseball pitchers Max Scherzer and Michael Schwimer.

There’s also Australian writer Les Murray and ancient politician Alexander the Great.

Contrary to popular belief, performer David Bowie doesn’t count as having heterochromia. He has one permanently dilated pupil due to a childhood accident – a condition known as anisocoria.

Matching doesn’t matter

As his character Bruno, Sacha Baron Cohen was right when he said things can be too ‘matchy-matchy’ like double denim or twins dressed in the same outfits. Two things that are supposed to match but don’t can either repel or attract. They may even suggest a supernatural superiority.

In a time when we add so much artificial colour to food, hair and even our skin in the form of makeup and fake tans, heterochromia is one of nature’s pretty genetic aberrations that isn’t imitated well with stick-on contact lenses. The real deal is what is really attractive.

Men and women agree that Black Swan actress Mila Kunis has the ideal eyes. One is brown, the other is green. Add the rest of her beauty into that package and she is the undisputed reigning queen of Heterochromatic Hollywood.