Identifying your natural eye colour can be an interesting exercise. Your eye colour results from the amount and quality of melanin pigments in your iris. The colour possibilities range from the darkest brown to the lightest blue and green. While some eye colours like brown and blue are common, others like amber and gray are rarer. Read on to learn about the different eye colours, how genetics determine your eye pigmentation, and tips for accurately identifying your eye colour.
Common Eye Colours
Here are some of the most common eye colours and their characteristics:
| Eye Colour | Description |
|---|---|
| Brown | Rich golden to dark brown hue. Very high levels of melanin. |
| Blue | Pale to deep ocean blue. Low levels of melanin. |
| Hazel | Mix of brown and green. Moderate melanin. |
| Green | Jade to emerald green. Low to moderate melanin. |
| Gray | Slate gray to silvery blue. Lowest melanin. |
Brown eyes are the most common worldwide, while blue, hazel and green eyes are rarer. Gray eyes are very uncommon globally but are sometimes seen in Northern and Eastern European countries.
Genetic Determinants of Eye Colour
Your eye colour is determined by the amount and type of melanin pigment in your irises. Here’s an overview of the genetics behind eye colour:
– **Melanin** – This pigment gives colour to your eyes, hair and skin. It absorbs light to produce darker colours.
– **Eumelanin** – A brown/black melanin that produces brown and black tones. Higher levels result in brown/black eyes.
– **Pheomelanin** – A red/yellow melanin that produces red and yellow hues. Mixed with eumelanin it can produce green, hazel and amber eyes.
– **Low melanin** – Having low levels of both melanins produces blue and gray eyes.
– **MCA** – The melanocortin 1 receptor (MCA) gene helps regulate melanin production. Certain variations in this gene reduce melanin levels and increase the likelihood of blue/green eyes.
– **HERC2** – The HERC2 gene regulates expression of the OCA2 gene that codes for melanin production. Mutations in HERC2 can turn off OCA2 resulting in low melanin blue/green eyes.
– **Multiple genes** – Recent research indicates that eye colour is a polygenic trait influenced by many genes working together. The main genes remain MCA and HERC2, but other modifier genes also have an influence.
Environmental & Health Factors
In addition to genetics, some health and environmental factors can also impact your eye colour:
– **Sun exposure** – Prolonged sun exposure increases melanin production, which can darken light coloured eyes over time. Wearing sunglasses limits this effect.
– **Medications** – Certain medicines like chloroquine and hormone treatments may gradually darken the iris. Consult your doctor about potential side effects on eye colour.
– **Injuries** – Physical trauma to the eye can sometimes cause flecks or heterochromia (two different eye colours). The change occurs due to a difference in melanin levels.
– **Diseases** – Some conditions like glaucoma, tumours, and pigmentary disorders may alter melanin content and lead to colour changes. See an ophthalmologist if you notice significant colour changes.
– **Aging** – Eye colour can darken slightly with age as melanin levels change over time. The effect is typically more noticeable in lighter coloured eyes.
Identifying Your True Eye Colour
Here are some tips for accurately determining your natural eye colour:
– Examine your eyes in natural daylight for the truest colour. Artificial lighting can distort colours.
– Look closely at the entire iris. Your eye may have a mix of colours or heterochromia.
– Avoid coloured contact lenses which can override your natural pigmentation.
– Check older photos to see your eye colour as a child. Your eye colour likely darkened over time.
– See an optometrist if you are uncertain. They can definitively determine melanin content and eye colour.
– Compare your eye colour to eye colour charts. Charts with gradations of colour can help pinpoint your hue.
– Ask others how they perceive your eye colour. Sometimes we have biased perceptions of our own eye shade.
– Test your genetic markers linked to eye colour. Certain DNA variations can predict blue/brown eyes.
Factors that Can Make Eye Colour Seem Different
Although eye colour is set genetically, certain factors may make your eyes appear a different shade than they really are:
| Factor | Effect on Eye Colour |
|---|---|
| Makeup | Coloured eye makeup like eyeshadow, liner, mascara, and false lashes can tint eyes or make them seem darker/lighter. |
| Clothing colour | Wearing certain colours near your face can reflect hues into your eyes through optical illusion. |
| Mood | Some studies show that pupil size changes with emotion, altering how dark/light eyes appear. |
| Bloodshot eyes | Redness from damaged blood vessels can temporarily colour eyes. |
| Lighting | Bright, outdoor light causes pupil contraction, making eyes look lighter. Dim indoor light dilates pupils, darkening eyes. |
Being aware of these factors can prevent false assumptions about changes in your actual eye pigmentation.
Special Eye Colour Variations
While most eyes are a single, uniform colour, some people have interesting variations in their irises:
– **Central heterochromia** – An inner ring of colour (usually around the pupil) that differs from the outer iris colour.
– **Segmented heterochromia** – Different colour patches in the same iris due to uneven melanin levels.
– **Complete heterochromia** – Two irises with distinctly different colours. Caused by uneven melanin or pigment distribution.
– **Alezzandrini’s syndrome** – A very rare mutation leading to blue eyes with a brown/yellow ring around the pupil.
– **Fuchs heterochromic iridocyclitis** – A condition causing one eye to become lighter than the other eye over time due to inflammation.
– **Horner’s syndrome** – Nerve damage that results in one pupil constricting more than the other, making one eye lighter.
– **Chimerism** – Possessing two different sets of DNA due to twin embryos fusing into one body, producing eyes of differing colours. Extremely rare.
These variations demonstrate the complex genetics and developmental processes that create the pigmentation in human irises and the resulting eye colours.
Conclusion
Identifying your true eye colour can be an interesting exercise in self-discovery. While most people haveeyes with uniform colouring, some have striking variations in hue and pattern. Your eye shade results from two types of melanin pigments that colour the iris based on instructions from various interacting genes. Besides this genetic programming, health conditions, medications, and environment can also affect eye colour. Being aware of these factors allows you to determine your natural eye colour accurately. Looking closely in natural lighting is the best way to analyze the specific hue and any colour variations within your irises. And remembering that colour perception is subjective allows you to decide which eye shade descriptor best matches your own eyes. So take a moment to look deeply into your eyes and appreciate their uniqueness.
