Heterochromia is a condition in which a person has two different colored eyes or variations in color within the same eye. This fascinating and often harmless trait can be present from birth or acquired later in life due to injury, disease, or medication. While heterochromia is rare, it draws attention due to its striking visual effect and potential medical implications in some cases.

What Is Heterochromia?

The term "heterochromia" comes from the Greek words heteros (different) and chroma (color). It refers to differences in the coloration of the iris, the part of the eye that controls pupil size and determines eye color based on melanin concentration.

What Are the Different Types of Heterochromia?

Heterochromia is categorized based on the pattern and extent of color variation:

Complete Heterochromia:

• One iris is a completely different color from the other (e.g., one blue eye, one brown eye)
  

Sectoral (Partial) Heterochromia:

• A segment of one iris differs in color from the rest of the same iris
  

Central Heterochromia:

• The inner ring around the pupil is a different color than the outer iris, often appearing as a radial burst
  

What Causes Heterochromia?

Heterochromia can be congenital (present at birth) or acquired due to external factors:

Congenital Heterochromia:

• Often inherited and harmless
  

• Associated with genetic conditions such as Waardenburg syndrome, Horner’s syndrome, or Sturge-Weber syndrome
  

• Usually not associated with any vision problems
  

Acquired Heterochromia:

• Can result from:
  

• Eye trauma or surgery
  

• Inflammation (e.g., iritis or uveitis)
  

• Certain medications (e.g., prostaglandin analogs for glaucoma)
  

• Tumors or pigment dispersion
  

• Systemic diseases affecting the eyes
  

How is Heterochromia Diagnosis and Evaluated?

If heterochromia is present from birth and not associated with other symptoms, it often requires no treatment. However, newly developed or changing eye color in adulthood should prompt an eye examination to rule out underlying causes.

Is Heterochromia Harmful?

In most cases, heterochromia is cosmetic and does not affect vision or eye health. However, when acquired or accompanied by other symptoms, it may signal underlying ocular or systemic conditions that need further investigation.