The color of our eyes continues to develop and change up to 3 years. However, it is really impossible for human eyes to be truly black. Our eyes appear black due to lighting, reflection from the clothing we wear, or the use of colored contact lenses.

We were curious as to why humans with naturally pure black eyes can only exist in works of fiction, and we came up with the following answer. We also found out what the rarest eye color is, which you can read about at the end of the article as a bonus.

Our Genes Just Won’t Allow It


There are about 16 different genes that are responsible for the color of our eyes. 2 of these genes are major factors, which are the HERC2 and OCA2 genes. These genes adjust the color of our eyes through the amount of melanin present in our iris.

The colors that result from melanin in our eyes can vary between a wide variety of hues, such as blue and gray, but the darkest possible color is very dark brown, not black.

We’d Probably End Up Crying All The Time


Black objects absorb more light to really look black. The excess light and energy it absorbs are converted into thermal energy.

This may mean that if our genes somehow made it possible for us to have true black eyes, our eyes might need a lot of tears to keep them from overheating and drying out.

Our Eyes Wouldn’t Be Safe Against Harmful Light


It would also be difficult for us to go out in broad daylight if we had black eyes. You see, the sun’s rays contain ultraviolet or UV light, and black objects tend to absorb more ultraviolet light than other colors.

Long-term exposure to ultraviolet light can deteriorate our eye health and cause problems, such as cataracts or skin cancer. However, thanks to our genetic makeup, the melanin that colors our iris protect us from ultraviolet light.

Studies show that melanin can kill more than 99.9% of the ultraviolet radiation it absorbs, protecting our eyes from damage caused by sun exposure.

Bonus: The Rarest Natural Eye Color


The rarest natural eye color is actually green. Only about 2% of the entire world population has green eyes.

There are also some rare conditions where people have red or purple eyes due to ocular albinism and others have different colored irises for each eye due to heterochromia.

What color are your eyes? What is your favorite eye color or what shade would you like to have?

Preview photo credit