Eye color: Encyclopedia II - Eye color - Colors

Eye color - Colors

Eye color - Brown eyes

The vast majority of the world's people have dark eyes, ranging from brown to nearly black. Light brown eyes are also present in many people, but to a lesser extent. Most of the original inhabitants of Africa, Asia, and the Americas have brown eyes. Brown eyes are also found in Europe, Oceania and North America, though within European populations they are not predominate to the same extent. In this population, brown eyes are genetically linked to brown or black hair.

Eye color - Black eyes

People with very dark brown irises may appear to have black eyes. This is fairly common in people of African, Asian and, to a lesser extent, Native American descent.

Eye color - Hazel eyes

Hazel is usually used to describe eyes that contain elements of both green eyes and brown eyes, sometimes transitioning from green at the edges to brown around the pupil. This should not be confused with irises that display a brown, yellow, or copper-colored ring around the pupil, as in the grey iris shown below.

Eye color - Blue eyes

Among human phenotypes, blue eyes are a relatively rare eye color. They are found mainly in people of northern European and eastern European descent, and to a lesser extent, in people of southern Europe, the Middle East, and Central Asia. South Asians may also have blue eyes, but this is uncommon, except amongst Pathans and in Kashmir and Punjab. Finland has the highest percentage of blue-eyed people. Many caucasian babies are born with blue eyes, though their eyes will darken, or change color. Most infants' eye color is set within a couple of days to a couple of weeks, though some people's eye color will continue to change for a number of years.

Blue is the colour of the indole monomer that when polymerised forms melanin.^{[citation needed]} . If both alleles for brown eyes (a polymerase gene) are absent or damaged, the blue colour remains. Hence blue eye color is a recessive trait.

In the mid-20th century after the dawn of color films, blue eyes were considered very desirable in those aspiring to be Hollywood actors and actresses. This became less true toward the latter half of that century.

Eye color - Grey eyes

Grey eyes are (an often lighter) variant of blue eyes. A wide variety of shades of grey exist, from the almost white (light grey) to dark (as in the picture at the right).

The underlying grey color may be tinted with various other colors, as in the greenish-grey eyes in the picture. "Steel blue" eyes are also found, ranging from a slightly desaturated blue to light blue-grey.

A yellow-, amber- or copper-colored ring is commonly seen around the pupil. This is a normal part of the iris, and should not be confused with Kayser-Fleischer rings. As with other colors, grey eyes are often seen to change color depending on the surrounding colors.

Eye color - Green eyes

Green eyes are rarer than brown, blue, and grey eyes, and are most often found in people of Celtic, Germanic, and Slavic descent. Hungarians (who are a Uralic people) have the highest percentage of green eyes of any population, close to 20%.

Interestingly, green eyes are also found, though in far lower proportions, from the Middle East to southern Asia. They are so common among Pashtuns that in Pakistan, Pashtuns are often called "Hurry Ankehian Wallay": the green-eyed people.

One of the most famous photographs ever published by National Geographic was a close-up of Sharbat Gula, a Pashtun girl with startling green eyes, taken in western Afghanistan by Steve McCurry in 1984. Details of her irises captured by the photograph were used to confirm her identity after she was relocated in 2003.

Eye color - Blue-Green eyes

A variant of blue eyes, blue-green eyes are quite rare and usually consist of an iris with a predominantly blue color, usually darker blue, with green streaks or stippling caused by a yellow- or copper-colored overlay. Yellow-, amber-, or copper-colored rings are often present around the pupil.

The exact color is often perceived to vary according to its surroundings. Wearing lighter blue colors or getting tanned tends to emphasize the blue components. Wearing bright red, green, and shades of yellow or brown can emphasize green components, or even give the impression of grey.

Eye color - Red eyes

The red-eye effect commonly appears in photographs, especially in those with light eyes. In animals including humans with albinism, the irises may appear red due to a lack of any pigment.

Note that different genes create melanins in the skin and hair than in the eyes.

Eye color - Heterochromia

Heterochromia (also known as a heterochromia iridis or heterochromia iridium) is an ocular condition in which one iris is a different color from the other iris (complete heterochromia), or where the part of one iris is a different color from the remainder (partial heterochromia or sectoral heterochromia). This uncommon condition usually results due to uneven melanin content. A number of causes are responsible, including genetics and Waardenburg syndrome. Trauma and certain medications can also cause increased or decreased pigmentation in one eye. Rock star David Bowie is said to have heterochromia iridium, apparently due to an eye injury incurred in his youth (in fact, he has his pupil permanently dilated, which makes the injured eye lose pigment and therefore appear green). Gracie Allen had two eyes of startlingly different colors, which some believe influenced her decision to stop acting when color television was widely adopted. Actor Joe Pesci and actresses Mila Kunis and Kate Bosworth also have different colored eyes. The French scientist Louis Pasteur, who proved the germ theory of disease, is also known to have had a green and a blue eye. On occasion the condition of having two different colored eyes is caused by blood staining the iris after sustaining injury.

Adapted from the Wikipedia article "Colors", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki