What Gives Our Eyes Color?

Eyes—the windows to our soul—but can we change them?

Our eyes are one of the most captivating features, often described as the “windows to the soul.” But beyond their beauty, why do eyes come in different colors? Is it possible to change their color? In this article, we’ll dive into how eye color works, the science behind it, and whether it’s something you can change.

Essentially, the color of your eyes is largely determined by genetics. The iris, the colored part of the eye, is composed of two layers: the stroma (front layer) and the pigmented epithelium (back layer). Eye color is influenced by the amount and type of pigment in the stroma, which is where the color comes from. There are two main types of pigments that affect eye color: melanin and pheomelanin. Melanin is the primary pigment responsible for darker shades like brown and black, while pheomelanin contributes to lighter shades like green and blue. The more melanin in the iris, the darker the eye color. The combination of these pigments, along with other genetic factors, is what determines whether someone has brown, blue, green, hazel, or gray eyes.

While eye color is inherited from parents, it’s not as simple as a direct inheritance. Eye color is controlled by multiple genes, with the OCA2 gene being one of the most influential, especially because it helps to regulate the amount of melanin produced in the iris. Looking at an example, people with two copies of the brown-eye allele (version of a gene) of the OCA2 gene have increased odds of having brown eyes. Now individuals with variations in this gene can have blue or green eyes, opposed to the common brown. Based on the variations of these same genes, shades of the same color are also affected, which is why some have lighter brown eyes versus the customary dark brown. It is important to note that eye color has the potential to change, especially in infants as they group up. Many babies are born with blue eyes, but as they age, their eyes may darken if more melanin is produced sometimes. 

With this information, the inevitable question arises—can you change your eye color after this period of time passes? The answer is a little more complicated than just a “yes” or “no.”

Recently, laser surgery has emerged as a potential way to change eye color permanently. The procedure involves using a laser in order to remove the melanin from the top layer of the iris, causing the eyes to turn a lighter shade. However, the procedure is highly controversial and not FDA-approved, as risks include damage to the iris, increased sensitivity to light, and even vision loss in extreme cases. This option remains risky, highly unrecommended.

On the other hand, there is ongoing research into gene therapies that could change the genetic makeup of the iris, potentially altering eye color. This would involve editing the genes responsible for melanin production, offering a more permanent and safer way to change eye color. However, this kind of technology, in its current pre-maturity, fails to consider the ability to edit melanin production only in the eyes. If not done properly, as of right now, there appears to be the possibility of inducing albinism, eradicating melanin in the body altogether, rather than editing melanin levels only in the eyes. This then opens up another box of issues.

It is important to note, however, that eye color doesn’t just affect how we look—it mainly influences how the eyes respond to light. People with lighter eyes (blue or green) generally have less melanin, making them more sensitive to bright light and more prone to conditions like macular degeneration. On the other hand, darker eyes (brown or black) have more melanin, which offers more protection against UV light and may lower the risk of certain eye diseases. Some studies have actually also shown that people with lighter-colored eyes are more likely to experience anxiety or pain sensitivity, although these findings are not universally accepted.

To conclude, eye color is a trait, determined by genetics, melanin levels, and a mix of other biological factors. While it’s possible to change your eye color temporarily with contact lenses, permanent changes are still in the realm of experimentation and come with significant risks. More options may become available in the future, but for now, the color of our eyes remains a natural gift that we have to accept—or enhance—on our terms.