One of the latest crazes in the anime, fashion video games, and graphic design communities is featuring characters with heterochromatic eyes. Heterochromatic eyes, or eyes with two different colored irises, have long captured the interest of passersby and artists. In these cutting-edge fashion games, we see characters gliding around their stages with one lavender and one aquamarine eye.
But how common is heterochromia? And is there a difference when it comes to vision?
The Rarity of Heterochromatic Eyes
Heterochromatic eyes are rare, so many people have questions about this condition. While heterochromatic people might have a presence in art, little is understood about why their irises vary in hue. Heterochromia of the eyes is present in only 1% of the population, so it’s no wonder it attracts attention. It is not specific to one group or populace, but people with common genes in the same family might be more likely to have the trait.
Types of Heterochromia
Heterochromia can be partial or complete, with the former being when the second eye is partially pigmented and, in the latter, an individual would have two completely irises that do not match in color. Interestingly enough, certain breeds of dogs and cats also can have heterochromatic eyes, with that being the dominant trait amongst that breed!
So what causes heterochromia and its various manifestations?
The Main Causes of Heterochromia
There are two causes of “heterochromatic iridis,” which largely relate to when the person developed the trait.
In one case, heterochromia is caused by genetics and autosomal, dominant traits that carry this predisposition. Although unique, heterochromia is not an aberrant, abnormal genetic mutation and rarely connected to genetic diseases in children.
Sadly, the other cause of heterochromia can be disease or injury to the eye in adults.
Facts About Congenital, Genetic Cases
If the irises are different colors at birth or after the newborn’s eyes have fully developed, then the condition is genetic. It is considered congenital, or “from birth,” in these conditions. A newborn should be checked out by an eye doctor to rule out the extremely unlikely genetic permutations that are the result of a handful of uncommon genetic diseases, such as Horner’s disease or Piebaldism. However, this condition is usually no cause for concern and even emulated and valued amongst trendsetters.
When someone has congenital heterochromia and testing rules out latent, rare genetic conditions, they tend to have normal vision. That is, people who have heterochromatic eyes might have perfect vision, or go on to require corrective lenses just as people with the same colored eyes would. The only difference between people with monochromatic and heterochromatic eyes is the amount of melatonin (a pigmentation chemical displaying color) that genetics allocates to the eyes. They do not perceive colors, or the color spectrum itself, in a way that varies from those with monochromatic eyes.
Heterochromia that occurs later in life and is referred to as acquired heterochromia should be treated with caution, since it is more often associated with genetic conditions, certain diseases, and even eye injuries that drain the irises of their pigment.
Possible Health Risks Associated with Adult Heterochromia
If one woke with sudden onset heterochromia, they should immediately consult an eye doctor, as certain forms of cancer can cause the iris to change shades.
In the case of adult-onset heterochromatic eyes, one should mark changes in vision or vision loss because this could be occurring in tandem with trauma to the eye from disease or injury. Eye care experts can help address your vision needs and changes, should this apply to you.