Rarest Eye Colors Spotted in Humans
Lots of different eye colors exist for a variety of reasons. Let's take a look at some of the rarest eye colors spotted in humans.Science
They say the eyes are the windows to the soul, but just how special are yours? You’re probably familiar with the same old shades but believe it or not there are people with silver, violet or even multicolored eyes out there. Let's explore some of the rarest eye colors in the world.
10. Ice Blue
You probably know at least one person with blue eyes, but as it stands only about 8-10% of the world’s population can say they have a pair of blue blinkers. In fact, a study conducted by the University of Copenhagen in 2008 revealed that all blue-eyed people are descendants of the first light-eyed human who emerged in South Eastern Europe around 10,000 years ago.
Eye color is determined by the amount of melanin in your iris, which is made up of the epithelium (the back of the iris) and the stroma, which is positioned in front.
While the epithelium contains dark brown pigments, the stroma can sometimes be totally devoid of melanin making it translucent, which is the cause of blue eyes. Interestingly, natural blue pigment doesn’t actually exist; it all has to do with the way light enters the eye.
While melanin absorbs light and presents it as brown, blue eyes scatter light back into the atmosphere in what is known as the Tyndall effect, similar to how the sky sometimes appears blue.
This 10,000-year-old genetic mutation affecting the OCA2 gene created a switch which can ‘turn off’ the production of melanin, meaning the clear stroma presents as blue.
Blue eyes are even less common in people of African American descent, and in such cases, the iris can often appear as a piercingly beautiful ice blue.
79% of us have brown eyes, but there is one rare variation which only 5% are lucky enough to possess, known as amber eyes. People with truly ‘amber’ eyes have a distinctly golden iris which can range from a strong yellow hue to a coppery russet tint, giving someone a seriously penetrating gaze.
This unique coloring is a result of reduced melanin levels alongside the increased presence of a yellowish pigment called lipochrome or pheomelanin.
Once again, the interference of light also has a lot to do with the way we perceive amber eyes through the process of Rayleigh scattering, which determines the way we see colors based on how light is reflected. In some conditions, amber eyes might seem closer to brown or hazel, but under natural lighting, there is no mistaking their almost mythical golden glow.
This rare variation is sometimes also referred to as ‘wolf eyes’ because such a vibrant coppery tint can also be commonly found in wolves, as well as animals like eagles, owls and fish.
Research shows that this color is more commonly found in countries in Asia and South America, but true amber eyes are still hard to come by. So, if you have them, you can consider yourself extremely special.
Green eyes are probably one of the first that comes to mind when you’re asked to list some of the most common colors humans can have, but people with genuinely green eyes only make up about 2% of the planet.
It’s easy to confuse green eyes with hazel which, while still very rare ,contain distinct flecks of brown due to a concentration of melanin on the outside of the iris, making them seem almost multicolored.
Truly green eyes lack this characteristic burst of brown or gold radiating outwards from around the pupil, and instead have a more solid emerald shimmer which couldn’t be mistaken for blue or brown.
Much like blue eyes, a natural green pigment doesn’t actually exist in humans, so what we see is created by a process called ‘structural colouring’. In this case, the iris has low levels of melanin alongside a small amount of yellow pheomelanin, meaning that when Rayleigh light scattering gives off a blue hue this mixes with the pheomelanin to create green.
In some parts of the world green eyes are completely absent, while this beautiful variation can be more commonly found in places like Northern and Central Europe. Green eyes also usually occur more often in women, and some notable examples of green-eyed celebs include Adele, Emma Stone and Amana Seyfried.
Claiming to have silver eyes might arise suspicions that you’ve inherited some supernatural genes, but about 1% of people out there do in fact have gray eyes.
An individual with these mysterious peepers can have an iris which ranges from cold steel to a smokier blue hue, but contrary to popular belief having gray eyes isn’t just a more creative way to describe a considerably pale blue shade.
Although significantly low melanin levels are again responsible for the translucent appearance of the stroma, the iris does not reflect blue light due to a certain amount of excess collagen.
The presence of this collagen interferes with the way light reflects in the iris, and the appearance of blue hues through the Tyndall effect is therefore blocked, presenting a more solid gray color instead.
In genetics, individuals are also said to have gray eyes when the dominant pigment inherited from their parents falls between blue, brown and green. Anthropologists theorize that early gray-eyed humans lived around the vast mountain systems of Eurasia, and nowadays lucky people with this rare eye color are most commonly found in Northern Eastern Europe.
Your pupil, which is essentially a hole located within the iris, appears black because light rays entering it are absorbed by tissues inside the eyeball, but is it possible to be born with completely black eyes?
The short answer is no (unless you’re a demon) because there isn’t a naturally occurring pigment capable of darkening your eye entirely, but there are a couple of reasons why a select few individuals might appear to have black eyes.
If staring into someone’s eyes seems more like looking into an endless black hole, the likelihood is that they just have an extremely dark brown iris which is hard to distinguish from their pupils in any lighting.
The only naturally occurring color pigment in the iris is brown, and this comes from melanocytes, miniature melanin cells which absorb light rather than scatter it. This means that an overproduction of melanocytes corresponds directly with darker eyes, so people with dark brown to black eyes just have more melanin in their iris than the rest of us.
A bizarre condition called ‘Aniridia’ can also be responsible for seemingly black eyes, though, as a chromosome mutation causes an almost complete absence of the iris. In reality, there is a small ring of iris tissue, but the grossly enlarged pupil makes it impossible to spot.
This rare disorder affects around 1 in 100,000 people and can cause side effects like light sensitivity and blurred vision.
You might have heard of the popular internet myth about a genetic mutation called ‘Alexandria’s Genesis’ which supposedly causes purple eyes during puberty, while others might feel nostalgic over Actress Elizabeth Taylor’s famous violet eyes – but is there any truth behind this sought-after color?
Simply put, the chances of actually having such an unusual characteristic are second to none, because there’s no purplish pigment capable of creating it. However, in certain cases (like Elizabeth Taylor's) the palest blue eyes with a tiny amount of melanin can have a violet tinge when certain light also reflects the blood vessels within the eye.
Interestingly, Taylor’s Amethyst eyes were also enhanced by a rare genetic mutation called ‘distichiasis’ which caused her to have a freaky double row of eyelashes.
People with albinism also have a much higher chance of having violet-presenting eyes because of the extreme lack of pigmentation in their skin and therefore melanin in their iris. A reduced number of melanocytes can cause almost colorless eyes which are easily affected by sun damage, giving them a more purplish hue.
Albino fashion model Natasya Kumarova has fascinatingly beautiful eyes which can appear violet under certain lights, but for the rest of us it seems like having purple eyes will remain a pipe dream.
For centuries humans have associated red eyes with all things evil, and although we’re used to seeing red eyes in flash photography, having crimson-hued peepers is nothing but a work of fiction. Or, is it?
As we’ve learned, brown is the only pigment that can occur naturally within the iris, while all other colors are a result of varying degrees of light reflection, but red is a little more complex. In fact, it’s virtually impossible for the average person to have genuinely red eyes.
This is because, for the iris to have a distinctly pink shade, there needs to be a complete lack of melanin and collagen deposits, which allows light to bounce off the back of the eyeball. The ‘red’ color we then see is a direct reflection of the color of the retina and blood vessels in the eye, which also makes them extremely light sensitive.
It’s impossible for light to exit the eye this way under normal circumstances, therefore likewise violet eyes, this phenomenon almost exclusively exists within people with albinism.
This unusual process also occurs in albino animals like white rabbits, albino hedgehogs or certain snakes, all of which have blood-red eyes due to a lack of pigmentation to control and filter out light.
3. Different Colored Eyes
Although a tiny portion of the world’s population does have totally unique eye colors, most of us will have brown or blue eyes. But there are some lucky individuals who ended up with one of each! This mind-blowing phenomenon is known as ‘heterochromia iridum’ and it occurs in less than 1% of the world's population.
While incredibly rare, the unusual condition can be traced back to ancient times, and there’s even a record of an Eastern Emperor ‘Anastasius’ who was nicknamed ‘Dicorus’ which literally means “two-pupiled” because he had different colored eyes; one blue, and one brown.
In most cases this unique characteristic is hereditary, but it can also be acquired later in life through illness, eye trauma, use of certain medications or even old age. Surprisingly, heterochromia iridum occurs more commonly in dog breeds such as huskies, but we humans can develop the striking feature due to varying factors.
During infancy when eye color is still subject to change, the affected eye might be hyperpigmented (making it darker), or hypopigmented, causing it to appear lighter due to an uneven concentration and distribution of melanin within the iris tissues.
Heterochromia Iridum also happens to be one unlikely thing Mila Kunis, Josh Henderson and Michael Flatley all have in common. Indeed, they’re rich, famous and they also have cool eyes!
2. Multicolored Eyes
If there’s anything cooler than having two different colored eyes, it’s mixing those colors into one. This unbelievable variation is another strain of heterochromia iridum known as ‘sectoral heterochromia’ and it’s just as rare. In fact, you’d be lucky to encounter someone with this unique condition in your lifetime.
In these unusual cases, the distribution of melanin across a single iris is distinctly non-uniform, which means that light is both absorbed and scattered from different areas of the stroma at once.
This mostly manifests itself as a characteristic splash of brown or blue which stands out against the dominant shade, but occasionally a near 50/50 distribution can result in a breath-taking iris which is split down the middle.
Although officially classed as a ‘rare disease’, sectoral heterochromia (alongside heterochromia iridum) poses no real health risks, so anyone blessed with it can pride themselves on being totally unique.
Plenty of celebs even have varying degrees of this multicolored phenomenon if you look close enough, including Benedict Cumberbatch, Henry Cavill and Kate Bosworth.
1. Cat Eyes
Regular humans with catlike eyes may seem like a plot for the most boring superhero movie ever made, but believe it or not, there is one extremely rare condition which can make someone’s eyes seem totally non-human.
Cat eye syndrome affects one in around 100,000 births and is commonly caused by a chromosome abnormality known as an inverted duplicated 22.
This means that each cell has at least one extra chromosome made up of genetic material from chromosome 22, which leads to the characteristic signs of cat eye syndrome, the most visible being a distinctly elongated pupil much like a feline or reptile.
This defect is scientifically known as an ‘iris coloboma’ which is basically a hole in the structure of the eye present during the early stages of prenatal development that fails to close. The often keyhole-shaped pupil can seem like it’s melting into the iris, making the color of the eye itself seem swirled or spotted from a distance.
The condition occurs sporadically during the formation of an egg or sperm and can then be genetically passed down. Depending on the severity of the deformation, affected individuals may experience impaired vision or even loss of sight, so maybe this is one rare set of eyes you don’t want to have.
What is, therefore, the rarest eye color in humans? Overall, an individual with red cat eyes would definitely be one in a million!
I hope you were amazed by these rarest eye colors spotted in humans. Thanks for reading!