Eye colour is one of the most fascinating features of human appearance. It can vary from light blue to dark brown, green, grey and even purple. But what is an even eye colour? If this isn't from birth and suddenly appeared, an eye exam may be recommended to understand the cause.
Understanding eye colour
Before delving into the concept of even-coloured eyes, it's essential to understand what determines eye colour. Eye colour is primarily influenced by the amount and type of pigments present in the iris, as well as by light scattering. The two main pigments are eumelanin (responsible for brown and black hues) and pheomelanin (which produces lighter hues such as yellow and red).
What are hazel eyes?
Hazel eyes, also known as “heterochromic” eyes, refer to a condition where a person's eyes are of different colours. There are two main types of heterochromia:
- Complete heterochromia: each eye is an entirely different colour. For example, one eye may be blue while the other is brown.
- Partial (or sectorial) heterochromia: part of an eye's iris is a different colour from the rest of the iris, which can create a “patchwork” effect in the eye.
Causes of heterochromia
Heterochromia can be congenital (present at birth) or acquired. Here are a few common causes:
- Genetic: most cases of heterochromia are hereditary and not linked to underlying medical conditions. Genetic variations in the genes responsible for pigment production can result in colour differences.
- Medical: certain medical conditions can cause acquired heterochromia, such as glaucoma, eye injuries or eye infections. Diseases such as waardenburg syndrome, horner syndrome and sturge-weber syndrome may also be responsible.
Celebrities and heterochromia
Many celebrities are known for having eyes of different colours, which often adds to their unique charm. For example, David Bowie had a form of partial heterochromia, although in his case, it was due to an eye injury that affected the dilation of his pupil. Actress Kate Bosworth is another famous example, with one blue eye and one partially brown eye.
Hazel eyes: is there cause for concern?
Generally speaking, heterochromia is benign and requires no treatment, especially if it's congenital. However, if a person develops heterochromia later in life, it's important to consult an optometrist to rule out any underlying medical conditions.
Hazel eyes are a fascinating natural phenomenon that adds to the diversity and beauty of human appearance. Whether a congenital or acquired condition, it is generally harmless and often considered a distinctive and attractive feature. If you or someone you know has different-coloured eyes, know that you are part of a rare and unique minority of the world's population.
The next time you come across someone with different-coloured eyes, you'll get a glimpse into the genetic and medical mysteries that can give rise to such singularity. And who knows, it may encourage you to take a closer look at the wonders that genetics can create.
