{"id":1824,"date":"2026-10-20T08:52:29","date_gmt":"2026-10-20T08:52:29","guid":{"rendered":"https:\/\/laseristanbulclinic.com\/eye-glossary\/eye-colour\/"},"modified":"2026-10-20T12:56:46","modified_gmt":"2026-10-20T12:56:46","slug":"eye-colour","status":"publish","type":"page","link":"https:\/\/laseristanbulclinic.com\/en\/eye-glossary\/eye-colour\/","title":{"rendered":"Eye Colour: What It Is, What Decides It and When a Change Matters"},"content":{"rendered":"\n
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  1. Home<\/a><\/li>
  2. Knowledge centre<\/a><\/li>
  3. Eye glossary A\u2013Z<\/a><\/li>
  4. Eye Colour: What It Is, What Decides It and When a Change Matters<\/span><\/li><\/ol><\/div>\t\t\t

    Eye Colour: What It Is, What Decides It and When a Change Matters<\/h1>\n\t\t\t\t\t\t

    Medically reviewed by {{surgeon}}<\/span><\/strong>, {{surgeon’s title and specialty}}<\/span>, on {{review date}}<\/span>. Last updated {{date}}<\/span>.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

    \"Illustration<\/figure><\/div>\n\t\t\t<\/div><\/div>\n<\/section>\n\n\n\n\n
    \n\t\t<\/svg>Definition<\/span>\n\t\t\t

    Eye colour<\/strong> (noun; US spelling eye color)<\/em>: the colour of the iris, the ring of tissue around the pupil that controls how much light enters the eye. It is set mainly by the amount of the pigment melanin in the front layers of the iris, and by how those layers scatter light: a lot of melanin gives brown, very little gives blue, and amounts in between give hazel and green. Eye colour is inherited through many genes, and a lasting change in an adult’s eyes, or two differently coloured eyes in a baby, should be checked by an eye doctor such as Do\u00e7. Dr. Muhammet Derda \u00d6zer (Do\u00e7. means Associate Professor).<\/p>\n\t\t<\/div><\/div><\/div><\/div><\/section>\n\n\n\n\n

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    Eye colour: key facts<\/h2><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t
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    <\/svg>What it is<\/span><\/dt>
    The colour of the iris, the coloured ring around the pupil<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>What sets it<\/span><\/dt>
    Melanin in the front layers of the iris, plus how light scatters in those layers<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Common natural colours<\/span><\/dt>
    Brown, hazel, green, blue and grey (amber is usually counted as a shade of brown)<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Most common<\/span><\/dt>
    Brown: more than half of people worldwide (American Academy of Ophthalmology, AAO)<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Rarest of the main colours<\/span><\/dt>
    Green: about 2% of people worldwide (AAO)<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>US snapshot (2014 poll quoted by the AAO)<\/span><\/dt>
    45% brown \u00b7 27% blue \u00b7 18% hazel \u00b7 9% green \u00b7 1% other<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Genes<\/span><\/dt>
    Many. The AAO says as many as 16; the main two, OCA2 and HERC2, sit on chromosome 15<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Babies<\/span><\/dt>
    Often born with blue-grey eyes; colour usually settles after about the first year<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Adults<\/span><\/dt>
    Colour is normally stable; a distinct change in one or both eyes needs an eye exam<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Specialist<\/span><\/dt>
    Ophthalmologist; at Laser Istanbul Clinic, Do\u00e7. Dr. Muhammet Derda \u00d6zer (uveitis, ocular tumours) and Prof. Dr. Ahmet Sat\u0131c\u0131 (glaucoma)<\/dd><\/dl><\/div>\n\t\t\t<\/div>\n\t\t<\/div><\/div><\/div><\/section>\n\n\n\n\n
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    \"Illustration<\/div><\/div>\n\t\t
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    What determines eye colour?<\/h2>\n\t\t\t\t\t\t\t\t

    Eye colour is determined by the amount of melanin in the front layers of the iris.<\/strong> Melanin is the same pigment that colours skin and hair. According to MedlinePlus, the US National Library of Medicine’s genetics service, brown eyes contain a large amount of melanin and blue eyes much less. The AAO adds that the brown colour comes from melanin and that the more melanin there is, the darker the brown.<\/p>\n

    Blue and green are not pigments.<\/strong> Blue eyes contain no blue pigment. With very little melanin in the front of the iris, light scatters and more blue light is reflected back out, in the same way that water and the sky look blue (AAO). Green works similarly: it is not only a matter of melanin but of how light scatters in the iris. That is why a blue or green eye can look different in different light, while a dark brown eye changes much less.<\/p>\n

    Everyone’s iris is unique.<\/strong> The AAO notes that the distribution of melanin in the iris differs from person to person, so two people with “blue eyes” rarely look exactly alike.<\/p><\/div>\n\t\t\t\t\t\t\t\t\t\t\t<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/section>\n\n\n\n\n

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    What are the natural eye colours, and how common are they?<\/h2>\n\t\t\t

    Researchers often group eye colour on a three-point scale of blue, green\/hazel and brown, but in everyday life people describe six shades. Reliable figures exist for only some of them.<\/p>\n\t\t\t

    Colour<\/th>What it looks like<\/th>What is behind it<\/th>How common<\/th><\/tr><\/thead>
    Brown<\/strong><\/th>From light honey to near-black<\/td>The most melanin in the front of the iris<\/td>The most common colour: more than half of people worldwide (AAO); 45% in the US (2014 poll)<\/td><\/tr>
    Hazel<\/strong><\/th>A mix of brown and green, often changing with light<\/td>A little more melanin than in blue eyes, giving brown and green tones<\/td>18% in the US (2014 poll)<\/td><\/tr>
    Green<\/strong><\/th>Pale to deep green<\/td>Little melanin plus light scattering<\/td>The rarest of the main colours: about 2% worldwide (AAO); 9% in the US<\/td><\/tr>
    Blue<\/strong><\/th>Pale to deep blue<\/td>Very little melanin; light scatters back as blue<\/td>27% in the US (2014 poll)<\/td><\/tr>
    Grey<\/strong><\/th>Silvery or steel grey<\/td>Low melanin and the way the iris tissue scatters light; usually grouped with blue in research<\/td>No reliable figure<\/td><\/tr>
    Amber<\/strong><\/th>Solid golden, yellow-brown or copper<\/td>Usually treated as a shade of brown<\/td>No reliable figure<\/td><\/tr><\/tbody><\/table><\/div>

    Which eye colour is the rarest?<\/strong> Green is usually named as the rarest of the main colours, at about 2% of people worldwide according to the AAO. Grey and amber may be just as uncommon, but studies tend to group them with blue and brown, so there are no dependable percentages for them. Red or pink-looking eyes are not a natural colour: they can occur in albinism, where the iris has little melanin and blood vessels show through (AAO).<\/p>\n

    Colour mix also differs by region. The AAO notes that brown eyes are more frequent in hotter parts of the world such as Africa and Asia than in Europe.<\/p>

    Eye colour chart & inheritance calculator <\/svg><\/a><\/div><\/div>\t<\/div><\/div><\/div><\/section>\n\n\n\n\n
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    \"Close-up<\/div><\/div>\n\t\t
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    How is eye colour inherited?<\/h2>\n\t\t\t\t\t\t\t\t

    Eye colour is inherited through several genes, not one, so it cannot be predicted exactly from the parents’ eyes.<\/strong> Two genes next to each other on chromosome 15 do most of the work. MedlinePlus explains that OCA2 makes the “P protein”, which helps melanin-producing structures in the iris mature, and that variants in a neighbouring region of HERC2 switch OCA2 down, producing less melanin and lighter eyes. Several other genes (including ASIP, IRF4, SLC24A4, SLC24A5, SLC45A2, TPCN2, TYR and TYRP1) play smaller roles and together create the continuum of shades.<\/p>\n

    Two scientific papers put figures on this:<\/p>\n