08 Aug Fun Eye Color Facts: A Guide to Eye Color Chart and Genetics
We’re dishing the truth about eye color myths and serving some cool eye color factoids you should know!
We’re sure you’ve heard some, if not all, of them. Those fun eye color trivia you or your friends might have shared once or twice. Well, we did some fact checking and dug up the truth about these myths and tidbits that have been going around for years. Discover the rarest eye color and learn other interesting facts about your eye color with our eye color chart and genetics guide.
Read on and get the low down on these eye color stories plus some amazing eye color trivia that’s worth sharing.
Only Caucasians can have blue eyes.
There have been so many reports of Asian and African people who were born with blue eyes. Blue or green (or colors other than the usual black or brown) can occur naturally in people with Asian or African ancestry. For some like celebrities Tyra Banks and Vanessa Williams, the occurrence could mainly be caused by European ancestry in their genealogy.
For others with no recorded or confirmed European ancestry, the phenomenon could be caused by some form of eye color genetics mutation. According to a recent research by a team of scientists from the Department of Cellular and Molecular Medicine at the University of Copenhagen, the occurrence of blue eyes in some individuals was actually caused by an eye color genetics mutation that happened 6,000-10,000 years ago. Originally, humans all had brown eyes, but this eye color genetics mutation caused a significant reduction in the production of melanin in the iris and the brown color was diluted to blue.
Having two different-colored eyes or heterochromia iridis can be a result of eye trauma.
According to an article by Habib Ur Rehman for the Canadian Medical Association Journal, “Eye colour is determined by the concentration and distribution of melanin in the iris.” And there are both genetic and physiologic factors affecting the maintenance and determination of eye color. While there are people who were simply born with it, including celebrities like Jane Seymour and Dan Akroyd, there are others whose heterochromia iridis was acquired through ocular trauma or a disease, like Mila Kunis who, at one point in her life developed a cataract in one eye changing its color.
University of Maryland Medical Center has provided a list of possible causes of heterochromia iridis in some individuals. This list includes bleeding (hemorrhage), foreign object in the eye, or some medications used for it, eye injury, mild inflammation affecting only one eye, and neurofibromatosis (a condition that causes skin color changes and nerve tumors), among others. High myopia (which can be inherited too) can also lead to heterochromia iridis as this can cause the development of chronic open angle glaucoma, which can change a person’s eye color due to damage. (Click here to find out how Invisalens can help cure myopia early on.)
A person can have a myriad of colors in a single iris.
It is possible to have multiple colors in one iris. According to the US Department of Health & Human Services’ Genetic and Rare Diseases Information Center, this condition is called segmental heterochromia iridis. Like complete heterochromia, sectoral heterochromia can be hereditary or acquired through injury or a disease. Famous people who have sectoral heterochromia iridis include Superman star Henry Cavill and American actress and model Kate Bosworth.
You are born with the eye color that you will be stuck with for the rest of your life.
There are babies born with blue eyes who later grow up to have brown eyes. According to Dr. Dana Johnson in an article for Wisconsin State Journal.
“Babies of African, Hispanic, and Asian descent are often born with dark irises (brown or black) that stay dark. Caucasian babies often have gray or blue eyes at birth.” This however can change over time since it takes time for their iris to produce melanin and for the iris to be the color it’s supposed to be. “Most of the color change to the iris occurs in the first 6 months of life,” Dr. Johnson adds. And this can still change until the child reaches 1 year old.
Because blue eyes are genetically recessive, it is the least common eye color.
While blue is actually becoming less common in recent generations, it is still the second most common eye color next to brown, according to an article by GB Healthwatch. Blue is followed by grey, and then green, which is believed to be the rarest color, with only 2% of the world’s population having it.
There are people who are born with even rarer eye colors such as purple, which are the result of albinism or the absence of pigment in a person’s skin, hair, and eyes.
Blue-eyed parents cannot have a brown-eyed child.
Contrary to traditional eye color charts you used in high school, a study by Richard Sturm of the Institute for Molecular Bioscience in the University of Queensland in Brisbane revealed that two blue-eyed parents can in fact produce brown or green-eyed children. This is because your eye color, like your hair color, is a polygenic trait.
Your “eye color is inherited from the action of multiple genes and not the result of a single gene,” according to Sturm. Polygenic traits arise as a result of the interaction of multiple genes. Eye colors are considered complex traits that are influenced by many and varying genes and the interactions between them. This is not to say that traditional eye color charts are not correct, but most scientists believe that these are incomplete and too simplistic to explain the vastly complex eye color genetics.
Modern eye charts, or what are now called eye color calculators, make use of recent studies about genetics and findings about eye color in computing/predicting a future baby’s eye color. This modern one by the Department of Genetics at the Stanford School of Medicine traces the eye color of not just the parents but also the grandparents from both sides to produce a more accurate prediction. Try it out yourself here.