Purple eyes are one of the rarest and most striking eye colors a person can have. Their unique violet or lavender hue sets them apart from the more common eye colors like blue, brown and green. But are purple eyes just a trick of the light, or are they a true and legitimate eye color? Let’s take a closer look at the science and genetics behind purple eyes.
What causes eye color?
Eye color is determined by the amount and quality of melanin pigments in the iris of the eye. Melanin comes in two forms: eumelanin which produces brown/black pigments, and pheomelanin which produces red/yellow pigments. The specific combination of these melanins produces different eye colors:
- Brown eyes have a lot of eumelanin
- Green eyes have some eumelanin and more pheomelanin
- Blue eyes have very little melanin overall
So the first key to purple eyes is having very little melanin in the iris. This provides a light base that allows other pigments to show through.
The role of light and optics
The second factor is the way light scatters and reflects off different pigments in the iris. Blue eyes appear blue because they have no melanin, and only scatter incoming light. Hazel and amber eyes appear brown/gold because they have a small amount of melanin that absorbs some light wavelengths.
Purple eyes are thought to be caused by an uncommon variant of the melanin pheomelanin that appears more red under some conditions, and the overall lack of melanin allows this pigment to show through. So while true purple irises may not exist, eyes can appear purple or violet under certain lighting conditions which reveal these unusual pheomelanin pigments.
Is eye color fixed at birth?
Eye color is primarily determined by genetics, but there are some key points to understand:
- Babies are usually born with blue/gray eyes that darken over the first year of life as melanin levels increase.
- The final eye color is not set until about age 3, though it typically stabilizes by 1 year old.
- Eye color can appear to change somewhat based on lighting conditions, clothing colors, and makeup.
So while genetics establish the maximum amount of melanin possible in the iris, the eye color you are born with may not be the final shade.
Genetics of eye color inheritance
The genetics of eye color inheritance are quite complex, involving up to 16 different genes. Here are some key points:
- Multiple genes influence melanin production, with OCA2 and HERC2 being major players.
- Blue eyes are a recessive trait, while brown is dominant.
- Green and hazel are intermediate colors produced by gene variants.
- Each parent contributes one allele (version of a gene) to their child.
The interactions of these alleles ultimately determine the amount and type of melanin produced. To have purple eyes, two copies of alleles supporting low melanin levels are likely needed.
| Parent 1 | Parent 2 | Child’s Genotype | Child’s Eye Color |
|---|---|---|---|
| Bb | Bb | BB, Bb, or bb | Brown, blue, or blue |
| Bb | bb | Bb or bb | Blue or blue |
In this table, B = brown allele, b = blue allele
Are true purple eyes possible?
Given the complex genetics involved, the chances of having perfect purple eyes is extremely rare. However, some unusual gene combinations could produce an eye color that appears vivid violet or lavender under the right conditions. This may be more likely in populations where blue eyes are already common.
There are unconfirmed reports of people in history having purple eyes, such as Queen Elizabeth I of England. Cleopatra was also said to have eyes that shifted color from blue to purple. While intriguing, these accounts are difficult to prove today.
Could purple eyed people have special powers?
Throughout history, people with exceptionally rare eye colors were thought to have mystical powers and psychic abilities. Those born with purple eyes were reputed to have the powers of foresight, intuition, and magic. However, there is no scientific evidence that eye color and psychic powers are linked.
That said, someone living with very unusual purple eyes would certainly have to handle a lot of attention and questions! In that sense, having purple eyes as a child could accelerate maturity and social skills.
Conclusion
Pure vivid purple eyes with no other color mixed in are likely not naturally possible in humans. However, there are some unique genetics that can produce eyes appearing light violet or lavender under certain conditions. This unusual eye color results from low melanin levels combined with unusual versions of the pigment pheomelanin. While extremely rare, eyes can take on a purplish look in the right lighting and angle. So if you ever meet someone with alluring violet-colored eyes, there may be some fascinating genetics at play!
