How a Child’s Eye Color Is Formed and Why It Can Change

While waiting for a baby to be born, many parents wonder what their child will look like and whom they will resemble. One of the most common questions concerns eye color. Although appearance as a whole is impossible to predict, eye color can be explained to some extent through biology and genetics. Several factors influence it, and the process is far more complex than it may seem at first glance.

Eye color is determined by the iris, which is located in front of the lens and controls the amount of light entering the eye. Its shade is genetically programmed and depends on the information inherited from both parents. In the past, it was believed that eye color was controlled by a single gene, but modern research has shown that dozens of genes are involved, each contributing to the final result.

The key factor in eye color formation is the pigment melanin. The more melanin present, the darker the eyes appear. When melanin levels are low, the iris looks lighter. Other pigments also play a role, and in combination with melanin they can produce shades such as green or hazel. It is the balance of these substances that ultimately determines eye color.

There is a common belief that dark eyes are a dominant trait and light eyes are recessive. In reality, the situation is much more complicated. Eye color is not defined by a simple combination of two traits. Genes such as OCA2 and HERC2 are especially important. OCA2 influences melanin production, while HERC2 regulates how actively this pigment is expressed. The specific versions of these genes passed on to a child shape their unique eye color.

Eye color can change during the first years of life. Many babies are born with light colored eyes because melanin has not yet been evenly distributed. During the first year, and sometimes up to the age of five or six, melanin levels may increase, causing the eyes to darken. However, dramatic changes are unlikely. If a child is born with dark eyes, they will not become light later on.

With age, eye color can also change slightly. In older adults, melanin levels may decrease, making the iris appear lighter. In rare cases, changes in eye color are linked to eye diseases that affect the structure of the iris and may be accompanied by vision problems.

Genetics remains a field full of surprises. A child may inherit the eye color of their parents or develop a shade that appeared in distant relatives. This wide range of genetic combinations is what makes every person truly unique.