Hazel Eyes: What Causes Hazel Eyes, And Who Has Them
Hazel eyes are a bit of a mystery.
For starters, people describe this magnificent eye color in many different ways. Some say it looks like hazelnut, while others call it golden or brownish green. One of the reasons it's so hard to describe hazel-colored eyes is that the hue itself seems to change, depending on what you wear and the type of lighting you are in.
To complicate matters further, although hazel eyes appear to contain hues of green, amber and even blue, these color pigments don't exist in the human eye. So where does this stunning color come from?
What Determines Eye Color?
Most of us were taught in high school science class that we inherit our eye color from our parents, and that brown eye color is dominant and blue is recessive (so two parents with blue eyes cannot have a child with brown eyes because neither parent carries the dominant form of the gene for brown eyes).
Hazel eyes often have a mixture of green, brown and amber hues. Their color can be hard to describe, since ambient lighting and clothing colors can affect your perception of them. [Enlarge]
But it turns out the story is more complicated than that.
More recent research has shown that up to 16 genes (not just one or two) may influence eye color, which makes predicting eye color much more difficult.
Due to variations in the interaction and expression of multiple genes, it's hard to say for sure what color a child's eyes will be based on the color of his or her parents' eyes. For example, we now know it's possible for two blue-eyed parents to have a child with brown eyes something the old model of eye color inheritance would have deemed impossible.
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Also, eye color can change dramatically in the first few years of life; many white, non-Hispanic babies are born with blue eyes and then develop brown, green or hazel eyes in childhood. This phenomenon has little to do with genetics, but it does help explain where hazel eyes come from.
What Causes Hazel Eyes?
The reason many white, non-Hispanic babies are born with blue eyes is that they don't have the full amount of melanin present in their irises at birth. In the first few years of life, more melanin often develops in the iris, causing blue eyes to turn green, hazel or brown.
Babies whose eyes turn from blue to brown develop significant amounts of melanin. Those who end up with green eyes or hazel eyes develop a little less.
Babies of African-American, Hispanic and Asian ethnicities usually are born with dark eyes that stay brown throughout life. This is because these individuals naturally have more melanin in their eyes and skin, compared with non-Hispanic whites.
Light Absorption And Scattering
Remember, there are no blue, green or hazel pigments in the eye. Eyes merely have different amounts of melanin, which is dark brown.
So how can a dark brown pigment create blue, green or hazel eyes? This is possible because of two processes:
- Melanin in the iris absorbs different wavelengths of light entering the eye.
- Light is scattered and reflected by the iris, and some wavelengths (colors) scatter more easily than others.
Eyes with high concentrations of melanin absorb more light entering the eye, so less is scattered and reflected back from the iris. The result is a brown eye color.
In eyes with lower concentrations of melanin, less light is absorbed, and more is scattered and reflected by the iris. Since light rays with shorter wavelengths (blue and green light) scatter more easily than light rays with longer wavelengths (red light), eyes with less light-absorbing melanin appear green or hazel, and eyes with low concentrations of melanin appear blue.
Also, the distribution of melanin can vary in different parts of the iris, causing hazel eyes to appear light brown near the pupil and more green in the periphery of the iris.
Hazel Eyes Are A Work Of Art
Hazel eye color is both complex and magnificent, since its specific features are determined by so many factors including the amount and distribution of melanin in the iris, how scattering of light by the iris and pigment molecules affects color, and how perception of eye color is influenced by lighting and the color of our clothing and surroundings.
Just as it takes many strokes of the artist's brush to produce a masterpiece, hazel eyes involve the dynamics of several elements to create the unique work of art that's represented in every hazel eye.
Change Your Eye Color To Hazel
If your eyes aren't naturally hazel, but you've always wanted them to be, you can achieve your wish with color contact lenses. They won't actually change your eye color, of course, just the appearance of it.
Want to try hazel eye color? Ask your eye care professional for a prescription for color contact lenses. [Enlarge]
Contact lenses are available in many colors, so you'll have a choice of several shades of hazel. But it's not simply a matter of choosing a lens color you like; the natural color of your eyes has a role in determining which lenses you should wear.
If you have very light eyes, you might be able to use a lens with an "enhancement tint." This lens has a translucent color that lets some of your natural color show through. It's meant to enhance your natural eye color to make your light blue eyes a deeper blue, for example but if your eyes are light enough, you might achieve the hazel you want with an enhancement tint.
More likely, you'll need an "opaque tint." These lenses are designed to mask your natural color with a solid version of the color you desire. They're often used when the color you want to achieve is lighter than your natural color.
An eye care professional can show you various colors and help you make the right choice. Remember, contact lenses are a prescription item, and if you don't already wear contacts, you'll need an eye exam and a prescription before getting them even if your lenses don't need any corrective power in them.
For more information, visit our page about color contact lenses.
Genotype-phenotype associations and human eye color. Journal of Human Genetics. January 2011.
Characterization of melanins in human irides and cultured uveal melanocytes from eyes of different colors. Experimental Eye Research. September 1998.
Eye color changes past early childhood: the Louisville Twin Study. JAMA Ophthalmology. May 1997.
[Page updated September 22, 2016]