Eye color is determined by genetics, but it’s not as easy as just looking at the parents’ eye colors. Even if both parents have brown eyes, it’s possible for their child to end up with green or blue eyes. These traits can may be passed in the form of recessive genes, so long as both parents carry the gene. Read on to learn more about how eyes get their color and why eye color often changes over the early months.
How Eyes Get Their Color
Dark-skinned adults tend to have dark eyes. Adults with lighter eyes are more likely to also have lighter-colored skin. While there is very limited research on infant eye color, the same pattern seems to be true in babies. A 2016 study found most White babies are born with grayish-blue eyes, while Native Hawaiian, Pacific Islander, and Asian babies are often born with dark brown eyes. But this color can change once the baby’s eyes are exposed to light outside of the womb because the iris (the colored ring around the black pupil) has color-producing cells in it.
Melanin
Eye color is determined by melanocytes, which are cells that secrete the protein melanin. Melanin is what influences skin, hair, and eye color. The iris contains melanocytes, and these cells respond to light by increasing melanin production, usually over the first year of life. Depending on how much melanin is secreted, your baby’s eye color may slowly begin to change after birth. If your baby has blue eyes, their melanocytes are secreting only a little melanin. If they secrete just a little bit more, your baby’s eyes will look green or hazel. If your baby has brown eyes, the melanocytes are secreting a lot of melanin.
Genetics
There are as many as 16 different genes involved in determining eye color, but the two most common are the OCA2 and HERC2 alleles. These genes control for brown or blue and green or hazel. Ultimately, your baby’s exact eye color will depend on the combination of these 16 genes that they inherit from both of their parents. This is why, though rare, two parents with brown eyes can have a baby with blue eyes.
Eye Color Concerns
Sometimes children are born with irises that do not match in color. This condition, known as heterochromia, is typically present at birth (where it is called congenital heterochromia). It generally does not cause any negative symptoms. But heterochromia can also result from a health condition or trauma. For example, Horner’s syndrome, which is a disruption of the nerve pathway from the brain to one side of the face and eye, can cause unexpected changes in eye color. The affected eye often has a lighter color than its counterpart. Waardenburg syndrome is a group of genetic conditions that can also cause changes in eye coloring. Children with this condition often have very pale blue eyes, have one blue eye and one brown eye, or have one eye that segments into two different colors. If you notice any unusual appearance in your baby’s eye color, contact your pediatrician. They may refer you to an ophthalmologist.
Predicting Eye Color
Because there is still a lot that is not understood about the interplay among genes and their role in determining eye color, it is hard to make predictions about what shade your baby’s eyes will end up being. But there are some probabilities that are worth noting:
Two blue-eyed parents: There is a high probability that the baby will have blue eyes, but this isn’t guaranteed.Two brown-eyed parents: Odds are that the baby will have brown eyes, but if either or both parents have family members with blue or lighter-shade eyes, there is a chance that the baby could have an eye color other than brown.One blue-eyed parent, one brown-eyed parent: There is about a 50/50 chance that the child will have blue eyes.One or both parents with green or hazel eyes: The baby could have green or hazel eyes, but it is difficult to know for sure.
Generally, changes in eye color go from light to dark. So if your child initially has blue eyes, their color may turn green, hazel, or brown. But if your baby is born with brown eyes, it is unlikely that they are going to become blue.
Eye Color and Light Sensitivity
People with blue, grey, or green eyes tend to be more light-sensitive than people with brown or black eyes. In fact, people with lighter eyes often experience photophobia, or light sensitivity, causing them to squint in sunlight or feel fatigued after sitting under fluorescent lights for a while. This sensitivity is due to the fact that people with light eyes have less pigmentation in multiple layers of their eyes. As a result, they are unable to block out the effects of bright lights or sunlight. With this in mind, parents should keep an eye on their kids when they are outside and look for signs that their child may need a break from the sunlight. Regardless of your baby’s eye color, it is best to protect their eyes when outside with sunglasses that offer UV protection.
Keep Your Baby’s Eyes Safe
Your baby’s eyes are sensitive, so you’ll want to make sure you take care to keep your baby’s eyes clean and protected from injury. First, during the initial months after birth, you may notice a slight discharge from your baby’s eyes. Carefully clean away this discharge when you are bathing them. You want to avoid constantly wiping your baby’s eyes with a tissue or washcloth. Second, be careful about what you allow your baby to play with. Babies have very little muscle control, so it is not uncommon for them to poke themselves in the eye. In fact, unintentional eye injuries are common even in infancy and, in some cases, can lead to permanent vision loss. Instead, give your baby safe, age-appropriate toys. Finally, you’ll want to pay attention to your baby’s eye alignment. While it is natural for a little squinting or misalignment to exist in the first few months, if it continues past the age of 6 months or if their eyes seem shaky in any way, talk to your pediatrician. They may refer you to an ophthalmologist.
