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What is Heterochromia? | Bard Optical

What is Heterochromia?

Child with heterochromia

Heterochromia is the medical term for when a person’s eyes are two different colors.

Heterochromia is caused by the production and delivery of melanin to the iris, more specifically, melanin being concentrated, or not concentrated, in both irises differently, resulting in the eyes being two different colors.

One usually contracts heterochromia through genetics, as it is usually inherited and contracted in infancy. There are other ways that heterochromia can be contracted, however. It can be caused as a result of different genetic conditions, such as mosaicism or chimerism. It can also be caused by a variety of diseases or injuries to the eyes.


Types Of Heterochromia

There are a few different types of heterochromia that depend on how much the person’s eye is changed.

  • Complete Heterochromia – This means the iris of one eye is completely different in color from the other. Complete heterochromia is the most drastic and noticeable type of heterochromia, and is most common among animals, especially cats.
  • Partial (or Sectoral) Heterochromia – This is when only a portion, usually half, of the iris is a different color. This can occur in one or both eyes. Partial heterochromia usually appears as an irregular spot in the person’s eye that is different in color and does not form a complete ring around the affected pupil.
  • Central Heterochromia – Referred to as “cat eyes,” this is when the colors of a person’s iris form two circles around the pupil, where the inner circle is one color and the outer circle is a different color. The outer circle is usually the person’s true iris color.


Heterochromia In The Real World

As earlier mentioned, heterochromia is common in different types of animals.

There are certain breeds of dogs that are more susceptible to heterochromia than others, such as:

  • Siberian Husky
  • Australian Shepherd
  • Border Collie
  • Great Dane
  • Dachshund


Some cats also have heterochromia, and their breeds include:

  • Turkish Van
  • Turkish Angora
  • Japanese Bobtail
  • Sphynx


There are also a number of celebrities that have heterochromia:

  • Dan Aykroyd
  • Kate Bosworth
  • Benedict Cumberbatch
  • Mila Kunis
  • Simon Pegg
  • Christopher Walken


Acquired Conditions

As earlier stated, heterochromia itself is a harmless condition. In most cases, the onset of heterochromia at birth causes no issues.

There are, however, a variety of conditions that people with heterochromia are more susceptible to.

A few of these include:

  1. Malignant Melanoma – Malignant melanoma in the person’s iris, or metastatic tumors of the iris.
  2. Ocular Melanosis – Characterized by increased pigmentation of a person’s eye and surrounding tissue.
  3. Acquired Horner’s Syndrome – Acquired from neuroblastoma, or injury, Horner’s syndrome affects the sympathetic nervous system around the neck.

This is not to say that those with heterochromia will experience any of these conditions, but rather that these conditions have a slight chance of being more present in those with heterochromia.


Taking Action

In the vast majority of cases, heterochromia is a benign condition. This does not mean, however, that you shouldn’t schedule regular exams with your eye doctor.

If your newborn is showing signs of developing heterochromia, you should schedule an exam, if only just to determine whether there are any other underlying conditions present.

Heterochromia can be a beautiful and unique condition to have.

Although it is not without risk, heterochromia poses no threat to your life or eyesight as long as you communicate effectively with your doctor about your symptoms.

Just be prepared to answer all the questions from those that look you in the eye for the first time!

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