Eye color is determined by the amount and type of pigment in the iris of the eye. The two main pigments that determine eye color are melanin and lipochrome. Melanin comes in two forms – eumelanin which produces brown/black pigment and pheomelanin which produces red/yellow pigment. The combination and concentration of these pigments within the iris produce the various eye colors we see.
The most common eye colors are brown, blue, hazel and green. However, some rarer eye colors are also possible like gray, violet and amber. One eye color that is often debated is orange. So is it really possible to naturally have orange colored eyes? Let’s take a deeper look.
Common Eye Colors
Here are some of the most common natural eye colors and their cause:
Brown Eyes – This is the most common eye color worldwide. Brown eyes get their color from melanin. People with brown eyes have a large amount of melanin in their irises. Dark brown eyes have more melanin than light brown eyes.
Blue Eyes – This is caused by low levels of melanin. Blue eyed people only have small amounts of melanin in their irises. This allows more light to scatter and reflect off the collagen fibers in the iris, producing a blue color.
Green Eyes – Green eyes are caused by moderate amounts of melanin. They have less melanin than brown eyes but more than blue eyes. The moderate melanin levels allow some light scattering to produce green hues.
Hazel Eyes – Hazel eyes shift between shades of brown and green. They often appear light brown or gold around the pupil and green on the outside of the iris. This is caused by a combination of moderate melanin levels and light scattering.
Gray Eyes – These eyes appear grayish blue/green. They are caused by very low levels of melanin similar to blue eyes. Some also consider them to be a lighter shade of blue.
What Causes Orange Eyes?
Natural orange eyes are very rare. Most orange eyes are caused by medical conditions like:
Ocular Albinism – This genetic condition reduces pigmentation in the eyes. It can cause the eyes to appear orange or red due to light reflecting off the blood vessels at the back of the eyes.
Heterochromia – Some people have this condition where their eyes are different colors. In rare cases, one eye may be orange or red-orange.
Lipochrome Deposits – Lipochromes are fat-soluble pigments that can accumulate in the iris. These deposits can cause yellow, orange, red or green rings to appear around the edge of the iris.
Iris Cysts – Certain types of benign cysts on the iris can cause a yellow-orange nodule to appear within the eye.
Eye Trauma/Damage – Injury to the iris sometimes results in hemorrhaging that can make the eyes appear reddish-orange. This is often temporary.
True Orange Eyes
While the conditions above can cause orange eyes, some people do naturally have true orange or amber colored eyes. This occurs when the iris contains a high concentration of lipochrome (a yellow pigment) along with some eumelanin (brown pigment).
Just like blue eyes, amber eyes are caused by a genetic mutation that reduces overall melanin production. However, enough pheomelanin (red/yellow) pigment remains to create orange hues when combined with reflective lipochrome pigments in the iris.
True orange eyes are extremely rare globally. They are most commonly found among certain populations in places like Afghanistan, Mongolia and some parts of West Africa. Some examples of populations with higher occurrences of true orange eyes include:
– Certain Pashtun tribes in Afghanistan
– The Hazaras of Afghanistan
– The Uyghurs of Northwest China
– The Berbers of Morocco/Algeria
– The Fulani people of West Africa
Among these groups, orange eyes occur at an estimated rate of 1-2% of the population. However, many of these regional statistics are based on limited photographic evidence. More extensive genetic and epidemiological studies are needed to confirm the precise frequencies. Overall, true amber eyes are thought to occur in less than 0.1% of people worldwide.
Conclusion
In summary, while orange eyes are extremely rare, they can occur naturally in some people due to genetics, pigmentation and light scattering effects. However, most orange-appearing eyes have an underlying medical condition. True amber eyes with no health issues are only found in very small populations scattered around the world. So in the end, yes orange is a possible, but very uncommon, human eye color.
Summary Table of Orange Eye Causes
| Cause | Description |
|---|---|
| Ocular Albinism | Genetic condition reducing iris pigment |
| Heterochromia | One eye appears orange due to lack of melanin |
| Lipochrome Deposits | Accumulation of yellow/orange pigments in iris |
| Iris Cysts | Benign orange nodules on the iris |
| Eye Trauma | Injury can cause temporary orange discoloration |
| Genetic Mutation | Reduced melanin allows lipochrome pigments to produce amber color |
