The color of a person’s eyes depends on the amount and type of pigment present. The main pigment that determines eye color is melanin. People with brown eyes have a lot of melanin in the iris of their eyes. People with blue eyes have much less melanin. Often, blue eyes look like they change between shades of blue and green.
Do blue eyes contain any green pigment?
Blue eyes get their color mostly from a lack of pigment, not from the presence of blue pigment. The iris has two layers – the front layer contains collagen fibers that scatter light. With little melanin in the front layer, more light is scattered, which makes the eye look blue. The back layer of the iris contains a pigment called lipochrome, which is yellowish brown. This backing causes blue eyes to also appear greenish at times.
Research has found that many people with blue eyes have a small amount of green pigment in their eyes as well as the lipochrome pigment. However, the amount of green pigment is very low compared to the amount of melanin in green or hazel eyes. So while true green eyes have a high concentration of the yellowish-green pigment, blue eyes only appear somewhat greenish because they are not strongly blue.
In summary, blue eyes get their color primarily from a lack of melanin. They can look green at times because of a small amount of green pigment and the yellowish lipochrome backing behind the iris.
Why do blue eyes look different shades?
There are a few different factors that cause blue eyes to look lighter or darker, greener or bluer at different times:
- Lighting – Bright sunlight makes blue eyes look more blue, while dark or cloudy conditions bring out more gray and green hues.
- Surroundings – Complementary colors like orange and blue enhance one another, so blue eyes look even bluer against warm backgrounds.
- Mood – Emotions cause changes in pupil size, affecting how light enters the eye and enhancing different flecks of color.
- Age – Infants often have lighter blue eyes that darken slightly over the first 3 years of life as melanin production increases.
- Injuries – Trauma to the eyes or lasik surgery can cause flecks of brown melanin to appear in blue eyes.
The amount of melanin present in the iris remains constant for an individual. But lighting conditions, surroundings, emotions, and injuries, can all change how that fixed amount of pigment is reflected, making blue eyes appear to change shades.
Do blue eyes turn green with age?
It is a myth that blue eyes turn green with age. As people get older, the lenses in their eyes start to yellow and the pupils get smaller. These changes can make blue eyes look lighter or more gray/green compared to when a person was younger. But the amount of melanin and actual color does not change over time.
While some elderly people with blue eyes notice their eyes looking greener now, it is an optical illusion. The shade of blue or green is not transforming. The following factors make blue eyes seem to change as people get older:
- Yellowing eye lenses – With age, the lenses become denser and start to yellow or brown, filtering out blue light.
- Smaller pupils – Pupils get smaller, altering the way light scatters to produce color.
- Changes in vision – Conditions like cataracts or macular degeneration distort color perception.
- Skin and hair color changes – Lighter skin and hair make blue eyes stand out less, seeming more grayish green in contrast.
While many notice their blue eyes looking different than when they were children, scientifically the amount of pigment in the iris remains fixed throughout life. The changing optics of the eyes mix up color perception, causing some blue to be filtered out so eyes seem less blue with age.
Can you have both blue and green in your eyes?
It is possible for eyes to be both blue and green. However, it does not happen too often since blue and green eye color come from different pigments.
For truly blue-green eyes, the iris needs to have:
- A low amount of melanin – this allows for light scattering that produces blue.
- A moderate amount of lipochrome – this yellow-brown pigment makes eyes look a little amber/green.
- Some deposition of the green pigment in the front layer – this adds a distinct green color.
When all these come together in the right ratios, the result can be an eye that is clearly both blue and green. The most common pattern is a blue-green gradient, with bluer tones around the edge and more green hues near the pupil.
However, true blue-green eyes are rare. Most of the time, eyes that look blueish-green really just have a low melanin content with a small green tint against the lipochrome backing. The appearance of having both blue and green comes from color theory – placing complementary colors like blue and greenish-yellow adjacent makes them both seem more vivid. When a blue eye has flecks of gold/green, the contrast makes the blues stand out more.
Do green eyes look blue?
Just as blue eyes can sometimes appear a bit green, green eyes can also look blue or gray at times. However, while blue eyes look green due to low melanin and the yellowish lipochrome layer, green eyes do not actually contain blue pigment.
There are a few reasons why green eyes can look blue or gray in certain situations:
- Lighting – Green eyes look more blue in bright light, and more gray/hazel in low light.
- Moods – Emotions cause the pupil size to change, affecting the colors that are reflected.
- Surroundings – Green eyes look more blue and vibrant against warm, orangey colors.
- Injuries – Trauma to the eye can release melanin, causing central heterochromia with a gray or brown spot.
The amount of the green/yellow pigment and melanin remains constant. But lighting, moods, and surroundings can mix up the way the fixed amount of color is perceived. Some people with green eyes notice their eyes looking blue-gray at times. But it is an optical illusion – the actual coloration does not change.
Conclusion
In summary, blue eyes can look green or contain green flecks, but it is from a low melanin content and the yellowish lipochrome layer behind the iris. True green pigment in blue eyes is very rare. Similarly, while green eyes can appear bluer or grayer at times due to lighting and other factors, they do not actually contain blue pigment. Blue and green eye colors originate from different pigments. So while the two colors can seem to mix at times due to optical illusions, it is uncommon for eyes to be a true mix of blue and green colors based on their genetic pigmentation.
| Eye Color | Causes | Appears Green/Blue due to… |
|---|---|---|
| Blue | Low melanin, some yellow lipochrome | Lipochrome backing, rare green tint |
| Green | Moderate melanin, high lipochrome | Lighting/angle, no blue pigment |