The Science Behind Eye Color

Last updated May 25, 2022 | By Robert Wilson
The Science Behind Eye Color image

Do you know what the science is behind eye color? Most people don't, but it's actually a pretty interesting topic! In this blog post, we will discuss the different genes that are responsible for determining eye color, and we will also take a look at some of the scientific research that has been conducted on this topic. So if you're curious to learn more about the science behind eye color, keep reading!

Genetics of Eye Color

Genetics play a role in determining a person's eye color. The gene responsible for blue eyes is recessive, which means it can be masked by other genes. Brown eyes are dominant, so a person only needs one copy of the brown-eye gene to have brown eyes. A person with heterochromia has two different eye colors. This condition is usually caused by a mutation in a genes that regulates the production of melanin, the pigment that gives color to the skin, hair, and eyes. Although genetics play a role in eye color, it is not the only factor. The environment, such as exposure to sunlight, can also influence eye color. For example, people with blue eyes often have lighter-colored eyes due to less melanin in the iris. Genetics are just one part of the story when it comes to eye color.


The cells in the iris that produce melanin are called melanocytes. The amount of melanin these cells produce is determined by the genes a person has, as well as the environment. The more melanin produced, the darker the eye color will be. The less melanin produced, the lighter the eye color will be. The production of melanin is also influenced by exposure to sunlight. The sun's ultraviolet rays can trigger the production of more melanin, resulting in a darker eye color. This is why people who live in sunny climates often have darker eyes than those who live in cooler climates.

Common Colors

The most common eye colors are brown, blue, and green. These three colors are determined by the amount of melanin in the iris. Brown eyes have the most melanin, while blue eyes have the least. Green eyes fall somewhere in between. Eye color is also affected by light scattering. This is why some people have hazel or amber-colored eyes. The light-scattering effect is more pronounced in people with lighter-colored eyes.


Heterochromia is a condition in which the irises of the eyes have different colors. It can be caused by a number of factors, including genetic disorders, injuries, and certain diseases. Heterochromia is relatively rare, affecting less than 1% of the population. The most common type of heterochromia is known as sectoral heterochromia, in which one sector of the iris is a different color from the rest. Heterochromia can also affect the whole iris, a condition known as complete heterochromia. Heterochromia is usually benign and does not cause any visual problems. In fact, many people with heterochromia find that their condition makes them stand out in a crowd. 

Red or Pink Eyes

Red or pink eyes are caused by a lack of pigment in the iris. The condition is known as albinism, and it is relatively rare. People with albinism often have other health problems, such as vision problems and skin cancer. Albinism is a genetic condition, and it can be passed down from parents to their children.

Biometric identification

Eye color can also be used for biometric identification. This is because every person's eye color is unique. The iris of the eye contains many different patterns, and these patterns can be used to identify an individual. The use of eye color for biometric identification is still in its infancy, but it has potential applications in security and law enforcement.

So there you have it! The science behind eye color is actually pretty interesting. Genetics play a role in determining eye color, but the environment can also influence the way the eyes look.