However, brown is not always the most common when it comes to particular ethnic groups.
Inside the iris is a variety of pigments that gives your eyes their color.
The combination of pigments and how they are distributed determine your specific hue.
Leland Bobbe / Getty Images
All of this comes down to genetics.
It also discusses the biological and genetic factors behind eye color.
Melanin, a yellow-brown pigment also responsible for skin tone, is the most predominant one.
Even people with blue or green eyes have some melanin in their eyes.
The pigment pheomelanin provides the color for green and hazel eyes.
A red-orange pigment, pheomelanin is also responsible for auburn hair.
This pigment is most commonly found in people with European ancestry, most notably in Ireland and Scotland.
The darkest pigment is eumelanin, a black-brown hue abundant in dark eyes.
The concentration of eumelanin determines the intensity of the eye color.
Green eyes are considered to be the rarestonly 2% of all people have them.
This happens because the iris is clear without melanin, allowing blood vessels to show through.
Heterochromia, having two different eye colors, is very rare.
Genetics of Eye Color
Multiplegenes help determine your eye color.
Genes affect how melanin and other pigments are made, moved, and stored in your body.
If you produce less pigment, then you end up with blue or green eyes.
High levels of melanin help to protect the eyes from damaging sun rays.
This helped to guard their vision against ultraviolet rays and helped them focus in bright light.
Researchers believe that lighter eyes appeared once Early Man left Africa and spread to Europe.
These areas had less sunlight, which meant there was less need for melanin.
The reason why someone’s eyes look blue has to do with the amount of melanin in the iris.
When there is less pigment, there is less light that can be absorbed.
The light is scattered and reflects the sky.
Eyes that have the smallest amount of melanin are blue.
Other pigments are also at play.
Green eyes, for example, have more pheomelanin than melanin.
Black eyes have more eumelanin.
The buildup of pigment takes time to develop in babies.
Eye color doe not typically change after that.
If it does, it can indicate a problem.
Effect on Eye Health
People with certain eye colors are more likely to experience different health conditions.
When you experience strong emotions, the body releases different brain chemicals that can constrict or dilate the pupil.
The lighter the hue of an eye, the more sensitive to light it is.
Pale blue or light grey eyes are more sensitive to light than dark blue eyes.
American Academy of Ophthalmology.Why are brown eyes most common?
American Academy of Ophthalmology.Your blue eyes arent really blue.
MedlinePlus.Is eye color determined by genetics?
American Academy of Ophthalmology.Why are my eyes changing color?
Grigore M, Avram A.Iris colour classification scalesthen and now.Rom J Ophthalmol.
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