Throughout the world, 79 percent of people have brown eyes and 5 percent have hazel eyes. These two colors are often considered the same color, but they are two distinct hues.
The iris of your eye is the part that has color. There are genes that work to determine whether your eyes are brown, hazel, or another color.
Both brown and hazel eyes are in the brown family. But hazel eyes feature other colors in addition to brown.
Table of Contents
- Hazel vs. Brown Eyes
- What Are the Unique Characteristics
- How Do Brown and Hazel Eyes Occur?
- Myths
- Pros and Cons
Pigmentation plays a major role in whether you have brown or hazel eyes. Melanin also determines how dark your eyes become.
Both of these eye colors come with their benefits. For example, if you have brown eyes, you tend to have a lower risk of macular degeneration.
Hazel vs. Brown Eyes: Differences and similarities
Hazel and brown eyes are often considered similar due to their shared brown pigmentation, leading many to categorize them together. In certain types of lighting, especially in low light conditions, hazel eyes can even appear to be light brown, further confusing the distinction between hazel vs. brown eyes.
Differences:
- Color Composition: The most striking difference between hazel and brown eyes lies in their color composition. Hazel eyes typically exhibit a combination of colors such as brown, amber, and green, with potential flecks of gray, blue, or gold. Brown eyes, on the other hand, are predominantly brown and may show only slight hints of green or other colors.
- Variation and Complexity: Hazel eyes often display a higher level of complexity in color pattern and can change appearance depending on lighting conditions. Brown eyes tend to be more uniform and consistent in color.
- Genetics: The genetics behind hazel and brown eyes also vary. Hazel eyes are less common and may result from a combination of genetic factors leading to a more diverse color spectrum. Brown eyes are the most common eye color worldwide, with a more straightforward genetic explanation.
Similarities:
- Shared Brown Pigment: Both hazel and brown eyes contain brown pigmentation. This is often why they are perceived as similar and may look alike in particular lighting situations.
- Appearance of Rings or Flecks: Both brown and hazel eyes can display rings or flecks of different colors within the iris. While more pronounced in hazel eyes, this phenomenon can also occur in brown eyes, adding to their distinctiveness.
- Perception Variation: The perception of both hazel and brown eyes can change based on the light and angle of viewing. While more pronounced in hazel eyes, brown eyes can also appear different in various lighting conditions.
- Uniqueness: One universal trait between hazel and brown eyes is their uniqueness. No set of hazel or brown eyes is exactly like another’s, leading to individual distinctions and making each person’s eyes special.
While hazel and brown eyes share some commonalities, they exhibit key differences, particularly in their color composition and complexity. Understanding the nuances of hazel vs. brown eyes enables a richer appreciation of the diversity and beauty present within human eyes.
The genes associated with eye color largely work in the transport, storage, and production of melanin — the pigment that results in eye color. Two of the common genes are HERC2 and OCA2.
A substance called a P protein works to mature melanosomes. These are a type of cellular structure that work to store and produce melanin. The OCA2 gene produces this protein. Since brown eyes have a lot of melanin, they have higher levels of P protein.
HERC2 has a region referred to as intron 86. Within this region is a DNA segment that controls OCA2 gene activity. HERC2 essentially turns the OCA2 gene off or on when it is necessary. With higher OCA2 activity, your eyes will be darker.
While these two genes are the ones that are primarily responsible for eye color, they are not the only genes that play a role. It is believed that other genes play a lesser role in eye color by combining with HERC2 and OCA2 to produce a variety of eye colors.
In many cases, you can predict a child’s eye color based on their parents. However, there are certain genetic variations that make some results unpredictable.
What Are the Unique Characteristics of Brown and Hazel Eyes?
The pigmentation and melanin levels of these eye colors are unique compared to other eye colors. The more melanin in the iris of your eyes, the darker they are.
Both hazel and brown eyes have a normal level of melanin presence at the back layer. At the front layer, brown eyes have a heavy melanin presence. At this layer with hazel eyes, the presence of green is higher than the presence of brown.
The pigment eumelanin is a dominant pigment in both hazel and brown eyes. Hazel eyes also have another dominant pigment known as pheomelanin.
Myths About Brown and Hazel Eyes
It was once believed that one gene determined a person’s eye color. It turns out that there could be up to 16 genes responsible for this.
Because there are so many genes at play, parents can have children with an eye color that neither of them have.
Pros and Cons of Brown and Hazel Eyes
Brown eyes are associated with increased and decreased risks of certain eye issues. When people have brown eyes, they tend to be at a lower risk for macular degeneration, eye cancer, and diabetic retinopathy. While the reason why is unclear, it is believed that this is due to brown eyes having greater protection due to a higher level of melanin.
Another possible benefit of hazel or brown eyes is that you may be less prone to damage from environmental noise. It is believed that the higher level of melanin may offer protective benefits for the brain’s nerves that may experience damage due to noise.
On the other side, brown eyes may be at a higher risk for developing cataracts. One study found that the risk may be twice as high as people with other eye colors. Exactly why this happens was not explored by the study.
Brown and hazel eyes have a variety of distinct characteristics that make them desirable colors.
References
- The World’s Population by Eye Color Percentages. World Atlas.
- Why Are Brown Eyes the Most Common? (August 2017). American Academy of Ophthalmology.
- Genotype-Phenotype Associations and Human Eye Color. (October 2010). Journal of Human Genetics.
- Iris Color and Cataract: The Blue Mountains Eye Study. (August 2000). American Journal of Ophthalmology.
- Eye Color Linked to Pain Tolerance in Pilot Study at Pitt. (July 2014). Pittsburgh Post-Gazette.
- Is Eye Color Determined by Genetics? (May 2015). Genetics Home Reference.
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