Can People Have Naturally Black Eyes? (And How Common Is It?)

Can people have black eyes?

No, humans cannot have truly black eyes. The colored part of the eye (the iris) biologically can’t be true black. People with eyes that appear black actually just have very dark brown eyes. The iris can be so dark that it’s almost indistinguishable from the black of your pupil (the dark circular opening in the middle of your eye), making someone’s eye color look “black.”

A very rare medical condition called aniridia can make eyes look black. Aniridia is a very rare (and very serious) genetic disorder where the iris is partially or fully absent, typically in both eyes. This means that the black pupils appear very large, making it seem like a person may have black eyes when really, the part of the eye that provides color is gone. The iris is a colored ring of muscle that relaxes or constricts to control how much light enters your pupil. When a room is dark, your irises will relax and your pupils will expand to take in more light. The opposite happens when it’s very bright; your irises will constrict and your pupils will shrink to block more light out. The color of your eye will be more apparent because your irises are enlarged, too. People with aniridia lose this control and have more sensitivity to light as a result. It can also lead to poor vision, eyes that don’t line up, and/or fast, uncontrollable “to and fro” eye movements.

How common are “black” eyes?

Very dark brown eyes that appear black are fairly rare. Brown is the most common eye color in the world—more than half of the global population has it—so you might think that near-black eyes are common.​ However, “brown” encompasses a wide range of shades from light ambers and hazels to very dark brown, making your chances of meeting someone with near-black eyes pretty slim. You're more likely to see someone with “black” eyes in Africa and Asia, where most people have dark brown eyes. Dark brown eyes are also common the the Middle East and some parts of South America and southern Europe. There’s not much data on exactly how many people have eyes that are so brown, they’re black. Some estimates say that a very small percentage of the global population might have eyes so dark brown they look almost black under certain lighting.

Advantages of Very Dark Eyes

Health benefits If you have brown or dark brown eyes, you’re less sensitive to light and UV rays than people with blue or light-colored eyes. But that’s not the only advantage of having dark eyes: You may be less at risk for age-related macular degeneration (vision loss) than people with light eyes. Compared to people with light blue eyes, you’re at less risk of type 1 diabetes, melanoma of the eye, and hearing loss from environmental noise pollution, too. Disadvantages: However, dark eyes are more likely to develop cataracts with age. Women with dark eyes were also found to experience more pain during childbirth than blue-eyed women, as well as more anxiety, depression, negative thoughts, and sleep disturbances.

Aesthetic benefits All eye colors are beautiful, but very dark shades have some special qualities that other eye colors lack (and vice versa). These include things like: Natural depth and warmth Contrast with the whites of the eyes Versatility with makeup choices Changes in hue in different lighting Enhanced appearance in photographs

What determines eye color?

Your genes control how much melanin is in your eyes, which determines their color. Melanin is a pigment your body produces that determines the color of your eyes, hair, and skin; the more melanin you have, the darker your features will be. Your eye color specifically comes from how much melanin is in the front layer of your iris. People with brown eyes have lots of melanin in this layer, while people with blue and light-colored eyes have far less. There are lots of genes involved in melanin production and eye color, but two of the most important are OCA2 and HERC2. OCA2 produces a protein that helps the cellular structures that produce and store melanin, influencing how much melanin is in your iris. HERC2 determines whether the OCA2 gene is “on” or “off.” When the gene is expressed (“on”), you produce more melanin. The science behind eye color today is a bit more complicated than scientists used to think. While you can still predict a baby’s eye color mostly accurately with a Punnett square and the parents’ eye colors, for example, the complexity of the genes involved means that unexpected results can occur in real life.

Some medical conditions can also influence your eye color(s). For example, people with albinism have very little or no melanin in their eyes. This leads to red or, in rare cases, violet-looking eyes; red comes from the reflection of the eye’s blood vessels, while violet comes from light scattering around trace elements of melanin. Heterochromia is a condition where one eye produces more or less melanin than the other, leading to two differently colored eyes. Anisocoria is another rare condition where one pupil is larger than the other, making that eye potentially appear darker than the other.

More Rare Eye Colors

Red, pink, or violet eyes When a person has albinism, the lack of pigment in their iris can make it seem red or pink due to the blood vessels in the eye. Sometimes, there is a trace amount of pigment (not enough to create a true blue color) that can look violet in certain lighting. How rare is it? Only about 1 in 20,000 people in the world have albinism, and not all albino people have red or violet eyes. Some estimate that as little as 0.01% of people have these eye colors.

Green eyes Green is the rarest “normal” eye color that isn’t caused by a condition like albinism. Green eyes have more melanin than blue eyes, but less than brown eyes. When that level of pigment is combined with a specific genetic trait that turns a brown-eyed allele “off,” the color green shines through. How rare is it? Only about 2% of the world’s population has green eyes.

Gray eyes Gray eyes happen when the front layer of your iris has very little melanin, while the back layer is richly brown with melanin, scattering the light in a specific way to look gray. The thin layer of collagen between these layers may also be slightly thicker in gray-eyed people, causing a “cloudy” effect that can look gray or blue-ish. How rare is it? About 3% of the world population has gray eyes.

Amber eyes Amber eyes are caused by a yellowish pigment called lipochrome, in addition to brown melanin. Unlike hazel eyes, which may have flecks of amber and can change hues in the light, amber eyes are consistently brown-yellow at all angles. How rare is it? About 5% of the global population has amber eyes.

Hazel eyes Hazel eyes can be green- or brown-dominant and contain flecks of green, light brown, gold, or amber. Because of this mix of shades, hazel eyes can “change colors” in different lighting. Hazel eyes are caused by a complex interplay of genes and are a “dominant” trait like brown eyes. How rare is it? About 5% or more of people have hazel eyes.

Frequently Asked Questions about Eye Color

How can you distinguish between dark brown eyes and truly black eyes? Observe the eye in bright light and look at it from several angles. It may be difficult to see the difference in colors in dim lighting, but bright illumination will warm up the brown pigments and make the iris and pupil easier to tell apart.

Does having “black” eyes affect your vision or eye health? No. Unless black-looking eyes are caused by aniridia (the absence of an iris), there is no negative health impact from having very dark brown eyes. However, some studies have shown that brown-eyed women are more sensitive to childbirth pain and may experience more depression and anxiety compared to women with blue or light-colored eyes.

Did all humans used to have brown eyes? Yes. As recently as 10,000 years ago, all humans had brown eyes. However, a random genetic mutation that caused the eyes to produce less melanin led to lighter colored, blue eyes. This mutation was passed down and continued to evolve, giving us the variety of eye colors we have today!

Can your eye color change? Your eye color won’t totally change colors (like from blue to brown), but some conditions can subtly affect your eye color. Developing cataracts can make your eye color appear more gray than it used to, for example. You might also get brown freckles in your iris from sun exposure over time, too. Fuchs heterochromic iridocyclitis is another condition that can cause your eye color to lighten due to inflammation. In rare cases, certain medications can cause a change in eye color (for example, some glaucoma medications can darken your eyes over time).