All About Your Baby Blues
If you have blue eyes, you’re part of a special group of people living all over the world. Read on to learn how you got your eye color, how rare it is, and what health risks might be associated with it. Plus, we’ll help you find the best glasses to make your eyes stand out.
Genetics of Blue Eyes
Your eye color is determined by two factors — genetics and melanin (pigment). Until recently, there were two generally accepted theories about genetics and eye color. The first is that if both of your parents had the same eye color, you would have that color too. The other is that brown eyes were genetically dominant and blue was recessive.
Research has since found that there is more to eye color than once believed. Science has shown that 16 genes — not one or two as previously thought — can impact the color of your eyes. So even if your parents both have brown eyes, that doesn’t mean you will.
Melanin and Eye Color
Melanin is the pigment in your body that’s responsible for your eye, hair, and skin color. Genetics is one factor that determines the amount of melanin you have. The more melanin in your body, the darker your eyes, hair, and skin.
The iris is the colored part of your eye that surrounds the pupil. It also contains melanin (hence, the color). The iris has two layers, and almost everyone has melanin in the back layer. People with a lot of melanin in both layers of the iris generally have brown eyes. People with little or no melanin in the front layer of the iris typically have lighter-colored eyes like blue, green, or gray.
Are All Babies Born with Blue Eyes?
No, studies have found that brown eyes are more common in newborns.
Many babies are born with light-colored eyes that change over time. This happens after the melanocytes — the cells that carry melanin in the body — are exposed to light.
Race also influences eye color. Many infants born with blue eyes are Caucasian and have less melanin than other babies. Black and Asian infants are often born with brown eyes due to a higher level of melanin.
How Rare Are Blue Eyes?
They’re more rare than you may think. About 27% of Americans have blue eyes, while globally, only about 9% of people have blue as their eye color.
It may also surprise you to learn that all blue-eyed people may be related. Through research, it was determined that about 10,000 years ago, someone was born in Europe with a genetic mutation.
This mutation turned off that gene’s ability to produce the brown color in eyes and instead resulted in the first blue-eyed person. It is believed that everyone with blue eyes alive today could be a descendant of this human.
Geography and Ancestry Affect Eye Color
Blue eyes are more common in some parts of the world than others:
- In Finland and Sweden, between 80% and 90% of the population has blue eyes.
- In the United Kingdom and Ireland, more than 50% of people have blue for their eye color.
In the United States, the majority of blue-eyed people have Scandinavian, British, Irish, and/or Eastern European backgrounds.
Health Risks
There are some additional health risks associated with light-colored eyes. The melanin that everyone has in their eyes absorbs UV light. This means it can help protect the retina at the back of the eye from the sun’s damaging ultraviolet (UV) rays.
Since people with blue eyes have less melanin, they tend to be more sensitive to light and more vulnerable to sun damage. If you have blue eyes, it’s a good idea to wear sunglasses that block 100% of UVA and UVB rays whenever you’re outside.
Less melanin also means that blue-eyed people have a higher risk of developing ocular uveal melanoma, which is a very rare type of eye cancer.
The good news is that people with blue and other light eye colors are less likely to get cataracts. However, they are just as likely as people with other eye colors to develop age-related macular degeneration (AMD).
