Determining your natural eye color can be confusing, especially if you have hazel eyes that appear to change between brown, green, and shades of gold. However, with a simple examination of the iris, you can identify the true pigmentation and genetic factors that determine your eye color.
What Elements Contribute to Eye Color?
Human eye color originates from two distinct factors:
- The pigmentation of the iris
- The way light scatters around the iris
The amount and quality of melanin pigments within the iris determine the base color of the eye. More melanin leads to darker eye colors, while less melanin produces lighter eye colors. Here are the most common iris pigment colors:
- Brown/black melanin – Produces brown/black eyes
- Yellow/golden melanin – Produces amber and golden eyes
- Blue melanin – Produces blue eyes
- Green melanin – Produces green eyes
- Gray melanin – Produces gray eyes
In addition to melanin content, the Tyndall effect also affects eye color. This phenomenon scatters light in the stroma, a thin layer behind the iris. The density of the stroma influences how light is reflected and absorbed, creating unique patterns and colors in the iris.
What Are the Most Common Eye Colors?
Here are the most commonly occurring natural eye colors from around the world:
| Eye Color | Frequency |
|---|---|
| Brown | Over 50% worldwide |
| Amber | 5% |
| Hazel | 5% |
| Green | 2% |
| Gray | 1% |
| Blue | 8% of Caucasians |
As shown, brown eyes are the most prevalent, with over half the global population having brown eyes. Blue eyes are quite rare globally but are more common among Caucasians, where 8% of the population has blue eyes. Amber, hazel, green, and gray eyes occur less frequently worldwide.
What Makes Eyes Appear to Change Color?
For people with hazel eyes, the iris may appear to shift between shades of brown, green, gray, and gold. However, hazel eyes are caused by a combination of ray and stromal melanin that blends together to produce multifaceted colors that change in certain lighting.
Here are some key factors that can make hazel eyes appear to shift in color:
- Melanin density – More melanin conveys darker browns, while less melanin shows more green/gold
- Lighting conditions – Dim lighting dilates pupils to reveal more color variations
- Clothing and background colors – Contrasting colors around the eyes will make the iris appear different shades
- Eye health and age – Younger eyes show more color distinction than older eyes
Hazel eyes are not actually changing color but rather showing the different hues and patterns inherent in the unique melanin combinations that produce hazel irises. The surrounding factors like lighting and clothing then emphasize different aspects of these colors.
How to Determine Your True Eye Color
To definitively determine your natural eye color, follow these steps:
- Examine your eyes in natural daylight for the clearest view of your irises. Artificial lighting can distort colors.
- Have someone look directly into your eyes from a close distance. Looking at eyes straight on reveals the true colors.
- Use a mirror to examine the details and patterns of your irises up close. Note the location of darker versus lighter areas.
- Take a high resolution photo of your eyes. Zoom in and observe the distinct color pigments and patterns.
- If you have hazel eyes, note whether brown, green, gold or gray dominates the overall eye color.
Doing a dilated eye exam at your optometrist is another way to get a magnified view of your irises to determine the proportions of color pigments. This will clearly show whether you have hazel eyes versus true green eyes, for example.
Genetic Factors That Determine Eye Color
Specific genetic traits passed down from parents determine melanin pigments and influence the ultimate eye color. Here are the key genetic determinants of eye color:
- EUMELANIN – A gene on Chromosome 15 causes brown/black melanin. Dominant over other genes so brown eyes are very common.
- PHEOMELANIN – A gene that controls yellow and red melanin pigments. Causes amber, gold and reddish eyes.
- OCA2 – Reduces overall melanin production. Results in gray, blue and green eyes if paired with light stromal scattering.
- HERC2 – Regulates OCA2 activity. Variants decrease melanin substantially leading to blue eyes.
The interactions between these genes produce different ratios of melanin that give rise to the full spectrum of human eye colors. Specific combinations can be predicted through genetic testing.
Changes in Eye Color Over Time
While genetics establish the base eye color, certain factors can lead to changes in eye color over someone’s lifetime:
- Infants – Many babies are born with blue/gray eyes that darken over the first 3 years of life as melanin levels increase.
- Injury – Heterochromia, or two different eye colors, can occur after injury to one eye that prevents future melanin production.
- Age – Eyes tend to get paler with age as melanin degrades and the stroma thickens.
- Medications – Some drugs like latanoprost glaucoma drops can increase melanin and permanently darken irises.
- Environment – Increased sun exposure causes more melanin activation and darker eyes.
While genetics provide the baseline, factors like aging and sun exposure will typically cause most eyes to become hazier and lighter over time as melanin fades.
Conclusion
Determining your true eye color can be tricky if you have hazel eyes or color changes early in life. But knowing your genetic makeup, carefully examining your irises, and accounting for environmental factors will help reveal your natural eye color. This can help provide insight into your ancestry and traits you may pass down to future generations.