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Eye color is a polygenic trait and is determined primarily by the amount and type of pigments in the eye's iris. Inheritance of quantitative traits or polygenic inheritance refers to the inheritance of a phenotypic characteristic that varies in degree and can be attributed to For the drug referred to as "pigment" see Black tar heroin. Eyes are organs that detect Light, and send signals along the Optic nerve to the visual areas of the brain The iris consists of Pigmented Fibrovascular tissue known as a stroma. [1][2] Humans and animals have many phenotypic variations in eye color. A phenotype is any observable characteristic of an Organism, such as its morphology, Development, biochemical or physiological properties [3] In humans, these variations in color are attributed to varying ratios of eumelanin produced by melanocytes in the iris. Melanin is a class of compounds found in the Plant, Animal and Protista kingdoms, where it serves predominantly as a Pigment. Melanocytes are cells located in the bottom layer (the Stratum basale) of the skin's epidermis and in the middle layer of the eye (the Uvea) [2] The brightly colored eyes of many bird species are largely determined by other pigments, such as pteridines, purines, and carotenoids. Pteridine is a chemical compound composed of fused Pyrimidine and Pyrazine rings Purine ( 1) is a heterocyclic Aromatic Organic compound, consisting of a Pyrimidine ring fused to an Imidazole ring Carotenoids are organic Pigments that are naturally occurring in Chromoplasts of plants and some other photosynthetic Organisms [4]

Three main elements within the iris contribute to its color: the melanin content of the iris pigment epithelium, the melanin content within the iris stroma, and the cellular density of the iris stroma. In biology and medicine epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body The stroma of the iris consists of fibers and cells The former are made up of delicate bundles of fibrous tissue a few fibers at the circumference of the iris have a circular [5] In eyes of all colors, the iris pigment epithelium contains the black pigment, eumelanin. [2][5] Color variations among different irises are typically attributed to the melanin content within the iris stroma. [5] The density of cells within the stroma affects how much light is absorbed by the underlying pigment epithelium. [5]

Contents

Determination of eye color

Eye colors can range from most common, brown, to least common, green. Rare genetic mutations can even lead to unnatural eye colors like black, red, and violet. Eye color is an inherited trait influenced by more than one gene. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance [6][7] Two major genes and multiple minor genes account for the tremendous variation of human eye color. [8] In humans, three genes associated with eye color are currently known: EYCL1, EYCL2, and EYCL3. [9][10] These genes account for three phenotypic eye colors (brown, green, and blue) in humans. A phenotype is any observable characteristic of an Organism, such as its morphology, Development, biochemical or physiological properties [3] Eye color usually stabilizes when an infant is around 6 months old. [11]

In 2006, the molecular basis of the EYCL3 locus was resolved. [12] In a study of 3839 people, researchers reported that 74% of total variation in eye color was explained by a number of single nucleotide polymorphisms (SNPs) near the OCA2 gene (OMIM: 203200). A single nucleotide polymorphism ( SNP, pronounced snip) is a DNA sequence variation occurring when a single Nucleotide - A, T Oculocutaneous albinism II (pink-eye dilution homolog mouse, also known as OCA2, is a human Gene. OCA2 was previously known because, when mutated, the gene can result in a type of albinism. Albinism (from Latin albus, "white" see extended etymology) is a form of hypopigmentary Congenital disorder, The recent study showed that different SNPs strongly associate with blue and green eyes as well as variations in freckling, mole counts, hair and skin tone. Freckles are clusters of concentrated Melanin which are most often visible on people with a fair Complexion. A mole, technically known as a melanocytic Nevus, is a small dark spot on human Skin. Hair color is the pigmentation of hair follicles due to the two types of melanin Eumelanin and Phaeomelanin. Human skin color can range from almost black (due to very high concentrations of the dark brown pigment melanin to nearly colorless (appearing reddish white due to the Blood The authors speculate that the SNPs may be in an OCA2 regulatory sequence and thus influence the expression of the gene product, which in turn affects pigmentation. A regulatory sequence (also called a regulatory region or a regulatory area) is a segment of DNA where regulatory proteins such as Transcription [13] A 2008 study demonstrated that a specific mutation within the HERC2 gene that regulates OCA2 expression is responsible for blue eyes[14] (see below).

Blue eyes with a brown spot, Green eyes and Gray eyes are caused by an entirely different part of the genome. As Eiberg said: "The SNP rs12913832 is found to be associated with the brown and blue eye color, but this single DNA variation cannot explain all the brown eye color variation from dark brown over hazel to blue eyes with brown spots".

Classification of colors

The perception of color depends upon various factors. These are the same eyes; however, depending on the light and surrounding hues, the eye color can appear quite different.
The perception of color depends upon various factors. These are the same eyes; however, depending on the light and surrounding hues, the eye color can appear quite different.

Iris color can provide a large amount of information about an individual and a classification of various colors may be useful in documenting pathological changes or determining how a person may respond to various ocular pharmaceuticals. [15] Various classification systems have ranged from a basic "light" or "dark" description to detailed gradings employing photographic standards for comparison. [15] Others have attempted to set objective standards of color comparison. [16]

As the perception of color is dependent on viewing conditions (e. Color vision is the capacity of an organism or machine to distinguish objects based on the Wavelengths (or frequencies) of the Light they reflect or emit g. the amount and type of illumination, as well as the hue of the surrounding environment), so is the perception of eye color. [17]

Eye color exists on a continuum from the darkest shades of brown to the lightest shades of blue. [6] Seeing the need for a standardized classification system that was simple, yet detailed enough for research purposes, Seddon et. al developed a graded one based on the predominant iris color and the amount of brown or yellow pigment present. There are 3 true colors in the eyes that determine the outward appearance; brown, yellow, and blue. How much of each color you have determines the appearance of the eye color. The color of the eyes in turn depends on how much of these colors are present. For example, green eyes have yellow and some blue, making them appear green. Brown eyes appear brown because most of the eye contains the brown color. The above is true for the species Homo sapiens. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus The iris color can vary in the animal world. Instead of blue in humans, autosomal recessive color in the species Corucia zebrata is black, whereas the autosomal dominant color is yellow-green. An autosome is a non-sex Chromosome. It is an ordinarily paired type of chromosome that is the same in both Sexes of a species. The Solomon Islands skink ( Corucia zebrata) is an Arboreal species of Skink endemic to the Solomon Islands. [18]


Amber

An amber eye
An amber eye
Human amber eyes displaying the yellow pigments.
Human amber eyes displaying the yellow pigments.

Amber eyes are of a solid color and have a strong yellowish/golden and russet/coppery tint. This might be due to the deposition of the yellow pigment called "lipochrome" in the iris (which is also found in green and violet eyes). [19][20] They are nicknamed "Wolf eyes" due to the high rate of the amber eye color in wolves.

The eyes of some pigeons contain yellow fluorescing pigments known as pteridines. Pteridine is a chemical compound composed of fused Pyrimidine and Pyrazine rings [21] The bright yellow eyes of the Great Horned Owl are thought to be due to the presence of the pteridine pigment xanthopterin within certain chromatophores (called xanthophores) located in the iris stroma. The Great Horned Owl, Bubo virginianus, is a large owl native to North and South America Chromatophores are pigment -containing and light-reflecting cells found in Amphibians Fish, Reptiles Crustaceans and [22] In humans, yellowish specks or patches are thought to be due to the pigment lipofuscin, also known as lipochrome. Lipofuscin is the name given to finely granular yellow brown Pigment granules composed of Lipid -containing residues of Lysosomal digestion [23]


Blue

A blue eye
A blue eye
Light eyes map
Light eyes map

Blue eyes contain low amounts of melanin within the iris stroma; longer wavelengths of light tend to be absorbed by the underlying iris pigment epithelium, and shorter wavelengths are reflected and undergo Rayleigh scattering. Rayleigh scattering (named after Lord Rayleigh) is the elastic Scattering of Light or other electromagnetic radiation by particles much smaller [5] The type of melanin present is eumelanin. [24] The inheritance pattern followed by blue eyes is considered similar to that of a recessive trait, however it is a polygenic trait (meaning that it is controlled by the interactions of several genes, not just one). [7] Eiberg and colleagues showed in a study published in Human Genetics that a mutation in the 86th intron of the HERC2 gene, which is hypothesized to interact with the OCA2 gene promoter, reduced expression of OCA2 with subsequent reduction in melanin production. Introns, derived from the term "intragenic regions" and also called intervening sequence (IVS are DNA regions in a Gene that are not translated into In Biology, a promoter is a region of DNA that facilitates the transcription of a particular Gene. [25]

The authors concluded that the mutation may have arisen in a single individual around the Black Sea region 6,000-10,000 years ago, perhaps suggesting that all people with true blue eyes are more closely related. The Black Sea is an inland Sea bounded by southeastern Europe, the Caucasus and the Anatolian peninsula ( Turkey However, blue eyes with brown spots around the pupil are not related to this mutation. [25]

Blue eyes are often found in Northern European countries, and are most common in Ireland[26], Germany[27] , Netherlands[28], Iceland[29] , Austria[30], Sweden[31], Norway[32], Denmark[33], Finland[34], Estonia[35], and the United Kingdom[36][37] They are also present in Southern Europe, the Middle East [38] (especially in Israel and Lebanon) and are also found in Afghanistan. Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands Iceland, officially the Republic of Iceland ( ( Ísland or Lýðveldið Ísland ( Austria (Österreich ( officially the Republic of Austria (Republik Österreich "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional The Kingdom of Denmark ( ˈd̥ænmɑɡ̊ (archaic ˈd̥anmɑːɡ̊ commonly known as Denmark, is a country in the Scandinavian region of northern Europe Finland, officially the Republic of Finland ( is a Nordic country situated in the Fennoscandian region of northern Europe. Estonia, officially the Republic of Estonia ( Eesti or Eesti Vabariik) is a Country in Northern Europe in the Baltic region The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The Middle East is a Subcontinent with no clear boundaries often used as a synonym to Near East, in opposition to Far East. For a topic outline on this subject see List of basic Israel topics. Lebanon (ˈlɛbənɒn Arabic: ar لبنان Lubnān) officially the Republic of Lebanon or Lebanese Republic (ar الجمهورية اللبنانية Afghanistan /æfˈgænɪstæn/ officially the Islamic Republic of Afghanistan ( Pashto: د افغانستان اسلامي جمهوریت, A 2002 study found the prevalence of blue eye color among Whites in the United States to be 33. 8% for those born between 1936 and 1951 compared to 57. 4% for those born between 1899 and 1905. [7]

Brown

Dark brown human iris
Dark brown human iris

Brown eyes are predominant in humans[39] and, in many populations, it is (with few exceptions) the only iris color present. [40] It is less common in countries around the Baltic Sea, such as Finland and Estonia. The Baltic Sea is a Brackish inland sea located in Northern Europe, from 53°N to 66°N Latitude and from 20°E to 26°E Longitude.

In humans, brown eyes contain large amounts of melanin (eumelanin) within the iris stroma, which serves to absorb light, particularly at the shorter wavelengths. Brown is the most common eye color. [5][24] Very dark brown irises may appear to be black. [41][42]



Gray

A steel blue-gray eye
A steel blue-gray eye
Female gray eyes
Female gray eyes
Male gray eyes
Male gray eyes

Gray eyes have less melanin than blue eyes, even though they are considered a darker shade of blue (like blue-green). They are most common in European Russia, Finland and the Baltic States. The Baltic states (Balti riigid Baltijas valstis Baltijos valstybės or Baltic countries are three countries in Northern Europe, all members of the It is unusually common in the Crimeean Peninsula and in people who are descended from cossacks . Under magnification, gray eyes exhibit small amounts of yellow and brown color in the iris.

A gray iris may indicate the presence of a uveitis. Uveitis specifically refers to Inflammation of the middle layer of the Eye, termed the " Uvea " but in common usage may refer to any inflammatory However, other visual signs make a uveitis obvious.

Visually, gray eyes often tend to appear to change between the shades of blue, green and gray. This is said to be influenced by the lighting and the surroundings (such as clothes, makeup, etc. ).

The Greek goddess Athena was renowned for having "owl-gray" (in Greek, γλαυκῶπις – glaukōpis) or "sea-gray" eyes. Greek mythology is the body of stories belonging to the ancient Greeks concerning their gods and Heroes the nature of the world and the origins and significance A goddess is a Female Deity. Many Cultures have goddesses Often deities are part of a polytheistic system that includes several deities ATHENA was an Antimatter research project that took place at the AD Ring at CERN. The Owls are an order of birds of prey. Most are Solitary, and nocturnal, with some exceptions (e Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly [43]

Green

Green eyes
Green eyes

Green eyes are the product of moderate amounts of melanin. Only 1-2% of the world's population has green eyes and it is the least common eye color. Hazel eyes are often mistaken for green, but true green eyes are rare. Green eyes are most often found among people of Northern and Southern European origin. Northern Europe is a term for the northern part of Europe. The United Nations defines Northern Europe as (Finland The term Southern Europe can have four definitions geographical political climatic phytogeographic Countries with a high percentage of green eyes are Iceland, Sweden, Denmark, Finland, Norway, Germany, Ireland and the Netherlands. Iceland, officially the Republic of Iceland ( ( Ísland or Lýðveldið Ísland ( "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. The Kingdom of Denmark ( ˈd̥ænmɑɡ̊ (archaic ˈd̥anmɑːɡ̊ commonly known as Denmark, is a country in the Scandinavian region of northern Europe Finland, officially the Republic of Finland ( is a Nordic country situated in the Fennoscandian region of northern Europe. Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands Green eyes are also common in Spain, Greece, Hungary, Poland, Ukraine, Israel, Lebanon, Georgia and in Jammu and Kashmir of Northern India and Northern Pakistan. Spain () or the Kingdom of Spain (Reino de España is a country located mostly in southwestern Europe on the Iberian Peninsula. Greece (Ελλάδα transliterated: Elláda, historically, Ellás,) officially the Hellenic Republic (Ελληνική Δημοκρατία Hungary (Magyarország 'mɔɟɔrorsaːg) officially in English the Republic of Hungary ( Magyar Köztársaság, literally Magyar (Hungarian Republic Poland (Polska officially the Republic of Poland Ukraine (Україна Ukrayina, /ukrɑˈjinɑ/ is a country in Eastern Europe. For a topic outline on this subject see List of basic Israel topics. Lebanon (ˈlɛbənɒn Arabic: ar لبنان Lubnān) officially the Republic of Lebanon or Lebanese Republic (ar الجمهورية اللبنانية Georgia ( საქართველო, Sakartvelo) is a Transcontinental country in the Caucasus region situated at the dividing line between ( Dogri: जम्मू और कश्मीर Urdu: جموں و کشمیر is the northernmost state of India. [44]

Hazel

This eye shows the shift in color from light brown to green.
This eye shows the shift in color from light brown to green.
Some eye colors are too mixed to identify properly, and are misidentified as hazel for simplicity's sake.
Some eye colors are too mixed to identify properly, and are misidentified as hazel for simplicity's sake.

Hazel eyes are due to a combination of a Rayleigh scattering and a moderate amount of melanin in the iris' anterior border layer. Rayleigh scattering (named after Lord Rayleigh) is the elastic Scattering of Light or other electromagnetic radiation by particles much smaller [23][5] Hazel eyes often appear to shift in color from a light brown to a medium golden-green. A number of studies using three-point scales have assigned "hazel" to be the medium-color between light blue and dark brown. [45][46][47][48][49][50][51] This can sometimes produce a multicolored iris, i. e. , an eye that is light brown near the pupil and charcoal or amber/dark green on the outer part of the iris (and vice versa) when observed in sunlight. Hazel is mostly found in some regions of the Americas, Europe, the Middle East, parts of Central Asia, parts of North India, Northern Pakistan and in Afghanistan. The Americas are the lands of the Western hemisphere or New World, consisting of the Continents of North America and South America The Middle East is a Subcontinent with no clear boundaries often used as a synonym to Near East, in opposition to Far East. Central Asia is a region of Asia from the Caspian Sea in the west to central China in the east and from southern Russia in the north to northern Pakistan in the south India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and Rarely, hazel eyes can be found in people of sub-saharan African and East Asian descent.

Definitions of the eye color "hazel" vary: it is sometimes considered to be synonymous with light-brown, gold, or other times with green or dark green. [52][41][45][47][50][53][54] [55][56] In North America, "hazel" is often used to describe eyes that appear to change color, ranging from light brown to green and even gray, depending on current lighting in the environment.

Red

The eyes of an albinistic person may appear red under certain lighting conditions due the very low quantities of melanin. Albinism (from Latin albus, "white" see extended etymology) is a form of hypopigmentary Congenital disorder, Melanin is a class of compounds found in the Plant, Animal and Protista kingdoms, where it serves predominantly as a Pigment. "True" red eyes also exist in albinistic populations, but are very rare. [57]

The red-eye effect in flash photographs makes the pupils (rather than the irises) appear red. The red-eye effect in Photography is the common appearance of Red Pupils in color Photographs of Eyes It occurs when using a photographic It is not related to eye color.

Violet

The appearance of "violet" eyes is thought to occur from the mixing of red and blue reflections. [58] Some albinos have eyes that appear violet. Albinism (from Latin albus, "white" see extended etymology) is a form of hypopigmentary Congenital disorder, Violet eyes are either a form of blue eyes or a mutation. [59]

Medical implications

Those with lighter iris color have been found to have a higher prevalence of age-related macular degeneration (ARMD) than those with darker iris color;[49] lighter eye color is also associated with an increased risk of ARMD progression. Macular degeneration is a medical condition usually of older adults which results in a loss of vision in the center of the visual field (the Macula) because [60] An increased risk of uveal melanoma has been found in those with blue, green or gray iris color. Uveal melanoma is cancer ( Melanoma) of the Eye involving the iris, Ciliary body, or Choroid (collectively referred to as the [61][62]

Eye color can also be symptomatic of disease. In particular, yellowing of the whites of the eyes is associated with jaundice and symptomatic of liver disease, including cirrhosis, hepatitis and malaria. Jaundice, also known as icterus (attributive adjective "icteric" is yellowish discoloration of the Skin, sclerae (whites of the eyes Cirrhosis is a consequence of chronic Liver Disease characterized by replacement of liver tissue by fibrous Scar tissue as well as regenerative Hepatitis (plural hepatitides) implies injury to the Liver characterized by the presence of Inflammatory cells in the tissue of Malaria is a vector -borne Infectious disease caused by Protozoan Parasites It is widespread in tropical and subtropical regions including

Anomalous conditions

Aniridia

Main article: Aniridia
Aniridia: Eyes wherein the irises are not present; the eyes appear to be two large pupils.
Aniridia: Eyes wherein the irises are not present; the eyes appear to be two large pupils. Aniridia is a rare Congenital condition characterized by the underdevelopment of the Eye 's iris.

Aniridia is a congenital condition characterized by an extremely underdeveloped iris which appears absent on superficial examination. Aniridia is a rare Congenital condition characterized by the underdevelopment of the Eye 's iris. [63]

Ocular albinism and eye color

Normally, there is a thick layer of melanin on the back of the iris. Even people with the lightest blue eyes, with no melanin on the front of the iris at all, have dark brown coloration on the back of it, to prevent light from scattering around inside the eye. In those with milder forms of albinism, the color of the irises is typically blue, but can vary from blue to brown. Albinism (from Latin albus, "white" see extended etymology) is a form of hypopigmentary Congenital disorder, In severe forms of albinism, there is no pigment on the back of the iris, and light from inside the eye can pass through the iris to the front. In these cases, the only color seen is the red from the hemoglobin of the blood in the capillaries of the iris. Such albinos have pink eyes, as do albino rabbits, mice, or any other animal with total lack of melanin. Transillumination defects can almost always be observed during an eye examination due to lack of iridial pigmentation. Transillumination is the transmission of light through tissues of the body An eye examination is a battery of tests performed by an Optometrist or Ophthalmologist assessing vision and ability to focus on and discern [64] The ocular albino also lacks normal amounts of melanin in the retina as well, which allows more light than normal to reflect off the retina and out of the eye. Because of this, the pupillary reflex is much brighter in the albino, and this can increase the red eye effect in photographs. The red-eye effect in Photography is the common appearance of Red Pupils in color Photographs of Eyes It occurs when using a photographic Edgar Winter's eyes are an example of this trait. Edgar Holland Winter (born December 28, 1946 in Beaumont Texas) is an American musician who had significant success in the 1970s and 1980s

Heterochromia

An example of heterochromia. The subject has one brown and one hazel eye.
An example of heterochromia. The subject has one brown and one hazel eye.
Main article: 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). In anatomy heterochromia refers to a difference in Coloration usually of the iris but also of Hair or Skin. It is a result of the relative excess or lack of pigment within an iris or part of an iris, which may be inherited or acquired by disease or injury. For the drug referred to as "pigment" see Black tar heroin. A disease is an abnormal condition of an organism that impairs bodily functions and can be deadly Injury or bodily injury is Damage or Harm caused to the Structure or function of the Body caused by an outside agent or [65] This uncommon condition usually results due to uneven melanin content. Melanin is a class of compounds found in the Plant, Animal and Protista kingdoms, where it serves predominantly as a Pigment. A number of causes are responsible, including genetics such as chimerism and Waardenburg syndrome. In Zoology, a chimera is an animal that has two or more different populations of genetically distinct cells that originated in different Zygotes if the Waardenburg syndrome is a rare Genetic disorder most often characterized by varying degrees of Deafness, minor defects in structures arising from the Neural Trauma and certain medications, such as some prostaglandin analogues can also cause increased or decreased pigmentation in one eye. Synthetic prostaglandin analogues are molecules which are manufactured to bind to a Prostaglandin receptor. On occasion, the condition of having two different colored eyes is caused by blood staining the iris after sustaining injury.

David Bowie (Jones) is a famous person often wrongly attributed with heterochromia. David Bowie (ˈboʊiː born David Robert Jones on 8 January 1947 is an English Musician, actor producer, and arranger. His apparent condition is due to a teenage injury. (One eye appears darker because the pupil is permanently dilated. ) American actress Kate Bosworth has sectoral heterochromia, resulting in a hazel section at the bottom of her right blue eye, while the left is completely blue. Catherine Ann "Kate" Bosworth (born January 2 1983 is an American actress. American Actress Elizabeth Berkley has sectoral heterochromia; her right eye is half green and half brown, and her entire left eye is green. Elizabeth Berkley (born on July 28 1974 As her love for dancing increased she became more interested in pursuing it professionally even traveling to New York to train with So does actor Anthony Head - he has a patch of hazel in his left eye where both eyes are blue-green overall. Anthony Stewart Head (born 20 February, 1954) is an English Actor and Musician who has appeared in Theatre, Television The lead vocalist of American band Rise Against, Tim McIlrath, has heterochromia; his left eye is blue while his right is brown. Rise Against is an American Punk rock band from Chicago Illinois that was formed in 1999 Tim McIlrath (born November 3, 1979) is the Guitarist and lead Singer for the American Melodic hardcore band Rise Against American actress Mila Kunis also has heterochromia, resulting in one blue eye and one brown-green eye. Mila Kunis She also has an older brother Her family moved to Los Angeles, California in 1991 American Actress Demi Moore also has heterochromia, by having one green eye, and the other hazel. Demi Moore (born Demetria Gene Guynes on November 11 1962 is an American Actress.

Eye color change

Often, paler newborns have blue eyes, which change to green, hazel, light brown or dark brown. This is possibly the origin of the idiom "being blue-eyed" (i. e. naïve; gullible).

It is thought that exposure to light after birth triggers the production of melanin in the iris of the eye. By three years of age, the eyes produce and store enough melanin to indicate their natural shade. While changes in eye color of infants are more common, even in adults, eye color changes are seen, most often as a result of exposure to the sun. Sunlight triggers melanin production in the eye, as it does to the skin.

Eyedrops containing a prostaglandin analogue (such as latanoprost) may result in a permanently darkened iris; these eyedrops are commonly used to treat open-angle glaucoma. Synthetic prostaglandin analogues are molecules which are manufactured to bind to a Prostaglandin receptor. Latanoprost (pronounced la-TA-noe-prost) ophthalmic solution is a topical medication used for controlling the progression of Glaucoma or ocular Hypertension Glaucoma is a group of diseases of the Optic nerve involving loss of retinal ganglion cells in a characteristic pattern of optic neuropathy. [66]

Eye color and red-eye effect

The photographic red-eye effect is more prominent in people with pale (blue or grey) eyes, and a similar effect (possibly the same) is observed in the eyeshine of blue-eyed cats and dogs. The red-eye effect in Photography is the common appearance of Red Pupils in color Photographs of Eyes It occurs when using a photographic The tapetum lucidum ( Latin: "bright tapestry" plural tapeta lucida) is a layer of tissue in the Eye of many Vertebrate animals that

References

  1. ^ Wielgus AR, Sarna T. "Melanin in human irides of different color and age of donors. " Pigment Cell Res. 2005 Dec;18(6):454-64. PMID 16280011.
  2. ^ a b c Prota G, Hu DN, Vincensi MR, McCormick SA, Napolitano A. "Characterization of melanins in human irides and cultured uveal melanocytes from eyes of different colors. " Exp Eye Res. 1998 Sep;67(3):293-9. PMID 9778410.
  3. ^ a b Morris, PJ. "Phenotypes and Genotypes for human eye colors." Athro Limited website. Retrieved May 10, 2006.
  4. ^ Oliphant LW. "Pteridines and purines as major pigments of the avian iris. " Pigment Cell Res. 1987;1(2):129-31. PMID 3507666.
  5. ^ a b c d e f g Huiqiong Wang, Stephen Lin, Xiaopei Liu, Sing Bing Kang. "Separating Reflections in Human Iris Images for Illumination Estimation." Proc. IEEE International Conference on Computer Vision, 2005.
  6. ^ a b Sturm RA, Frudakis TN. "Eye color: portals into pigmentation genes and ancestry." Trends Genet. 2004 Aug;20(8):327-32. PMID: 15262401.
  7. ^ a b c Grant MD, Lauderdale DS. "Cohort effects in a genetically determined trait: eye color among US whites. " Ann Hum Biol. 2002 Nov-Dec;29(6):657-66. PMID 12573082.
  8. ^ Eye color mocks easy rules
  9. ^ Rebbeck TR, Kanetsky PA, Walker AH, Holmes R, Halpern AC, Schuchter LM, Elder DE, Guerry D. "P gene as an inherited biomarker of human eye color." Cancer Epidemiol Biomarkers Prev. 2002 Aug;11(8):782-4. PMID 12163334.
  10. ^ "Eye color is more complex than two genes." Athro, Limited. Retrieved September 1, 2006.
  11. ^ Why Babies Are Born with Blue Eyes
  12. ^ Paul Rincon, Genetics of eye color unlocked, BBC News, 20 December, 2006.
  13. ^ Duffy DL, Montgomery GW, Chen W, Zhao ZZ, Le L, James MR, Hayward NK, Martin NG, and Sturm, RA "A Three–Single-Nucleotide Polymorphism Haplotype in Intron 1 of OCA2 Explains Most Human Eye-color Variation" Am. J. Hum. Genet. 2002 80:000, 2007.
  14. ^ 10.1007/s00439-007-0460-x
  15. ^ a b German EJ, Hurst MA, Wood D, Gilchrist J. "A novel system for the objective classification of iris color and its correlation with response to 1% tropicamide. " Ophthalmic Physiol Opt. 1998 Mar;18(2):103-10. PMID 9692029.
  16. ^ Fan S, Dyer CR, Hubbard L. Quantification and Correction of Iris Color." Technical report 1495, University of Wisconsin-Madison, Dec, 2003.
  17. ^ Color Perception
  18. ^ Jones, S. L. , Schnirel, B. L. , Subspecies comparison of the Genus: Corucia, Leeway Corucia Research Center - LCRC, Polyphemos, {2006} Volume 4, Issue 1. pp. 1-25.
  19. ^ Howard Hughes Medical Institute: Ask A Scientist
  20. ^ Eye Color
  21. ^ Oliphant LW. "Observations on the pigmentation of the pidgeon iris. " Pigment Cell Res. 1987;1(3):202-8. PMID 3508278.
  22. ^ Oliphant LW. "Crystalline pteridines in the stromal pigment cells of the iris of the great horned owl. " Cell Tissue Res. 1981;217(2):387-95. PMID 7237534.
  23. ^ a b Lefohn, A. , Budge, B. , Shirley, P. , Caruso, R. , and Reinhard, E. 2003. An Ocularist's Approach to Human Iris Synthesis. IEEE Comput. Graph. Appl. 23, 6 (Nov. 2003), 70-75. DOI= http://dx.doi.org/10.1109/MCG.2003.1242384
  24. ^ a b Menon IA, Basu PK, Persad S, Avaria M, Felix CC, Kalyanaraman B. "Is there any difference in the photobiological properties of melanins isolated from human blue and brown eyes?" Br J Ophthalmol. 1987 Jul;71(7):549-52. PMID 2820463.
  25. ^ a b Eiberg H, Troelsen J, Nielsen M, Mikkelsen A, Mengel-From J, Kjaer KW, Hansen L. "Blue eye color in human beings may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression" Human Genetics 2008 Jan 3. PMID 18172690
  26. ^ [1]
  27. ^ [2]
  28. ^ [3]
  29. ^ [4]
  30. ^ [5]
  31. ^ [6]
  32. ^ [7]
  33. ^ [8]
  34. ^ [9]
  35. ^ [10]
  36. ^ [11]
  37. ^ Rafnsson V, Hrafnkelsson J, Tulinius H, Sigurgeirsson B, Olafsson JH. "Risk factors for malignant melanoma in an Icelandic population sample. " Prev Med. 2004 Aug;39(2):247-52. PMID 15226032
  38. ^ http://carnby.altervista.org/troe/08-05.htm
  39. ^ Eiberg H, Mohr J. "Assignment of genes coding for brown eye color (BEY2) and brown hair colour (HCL3) on chromosome 15q. " Eur J Hum Genet. 1996;4(4):237-41. PMID 8875191.
  40. ^ OMIM - SKIN/HAIR/EYE PIGMENTATION, VARIATION IN, 1; SHEP1
  41. ^ a b Hammond BR Jr, Fuld K, Snodderly DM. "Iris color and macular pigment optical density. " Exp Eye Res. 1996 Mar;62(3):293-7. PMID 8690039.
  42. ^ Prieto JG. "Eye color in skin cancer. " Int J Dermatol. 1977 Jun;16(5):406-7. PMID 873674.
  43. ^ The Perseus Digital Library: Homeric Hymns
  44. ^ [12]
  45. ^ a b Zhu G, Evans DM, Duffy DL, Montgomery GW, Medland SE, Gillespie NA, Ewen KR, Jewell M, Liew YW, Hayward NK, Sturm RA, Trent JM, Martin NG. "A genome scan for eye color in 502 twin families: most variation is due to a QTL on chromosome 15q. " 1: Twin Res. 2004 Apr;7(2):197-210. PMID 15169604.
  46. ^ Albert DM, Green WR, Zimbric ML, Lo C, Gangnon RE, Hope KL, Gleiser J. "Iris melanocyte numbers in Asian, African American, and Caucasian irides." Trans Am Ophthalmol Soc. 2003;101:217-21; discussion 221-2. PMID 14971580.
  47. ^ a b Mitchell R, Rochtchina E, Lee A, Wang JJ, Mitchell P; Blue Mountains Eye Study. "Iris color and intraocular pressure: the Blue Mountains Eye Study. " Am J Ophthalmol. 2003 Mar;135(3):384-6. PMID 12614760.
  48. ^ Lindsey JD, Jones HL, Hewitt EG, Angert M, Weinreb RN. "Induction of tyrosinase gene transcription in human iris organ cultures exposed to latanoprost. " Arch Ophthalmol. 2001 Jun;119(6):853-60. PMID 11405836.
  49. ^ a b Frank RN, Puklin JE, Stock C, Canter LA. "Race, iris color, and age-related macular degeneration." Trans Am Ophthalmol Soc. 2000;98:109-15; discussion 115-7. PMID 11190014.
  50. ^ a b Regan S, Judge HE, Gragoudas ES, Egan KM. "Iris color as a prognostic factor in ocular melanoma. " Arch Ophthalmol. 1999 Jun;117(6):811-4. PMID 10369595.
  51. ^ Hawkins TA, Stewart WC, McMillan TA, Gwynn DR. "Analysis of diode, argon, and Nd: YAG peripheral iridectomy in cadaver eyes. " Doc Ophthalmol. 1994;87(4):367-76. PMID 7851220.
  52. ^ Understanding Genetics: Human Health and the Genome
  53. ^ Naldi L, Altieri A, Imberti GL, Giordano L, Gallus S, La Vecchia C; Oncology Study Group of the Italian Group for Epidemiologic Research in Dermatology (GISED). "Cutaneous malignant melanoma in women. Phenotypic characteristics, sun exposure, and hormonal factors: a case-control study from Italy. " Ann Epidemiol. 2005 Aug;15(7):545-50. PMID 16029848.
  54. ^ April Holladay. "Funny — you can't hide those lightening eyes." USATODAY. com. October 8, 2004. Retrieved September 17, 2006.
  55. ^ English JS, Swerdlow AJ, MacKie RM, O'Doherty CJ, Hunter JA, Clark J, Hole DJ. "Relation between phenotype and banal melanocytic naevi." Br Med J (Clin Res Ed). 1987 Jan 17;294(6565):152-4. PMID 3109545.
  56. ^ Hara T. "[Increased iris pigmentation after use of latanoprost in Japanese brown eyes. ]" Nippon Ganka Gakkai Zasshi. 2001 May;105(5):314-21. PMID 11406947.
  57. ^ NOAH — What is Albinism?
  58. ^ BBC - h2g2 - Determination of Eye Colour
  59. ^ NOAH — What is Albinism?
  60. ^ Nicolas CM, Robman LD, Tikellis G, Dimitrov PN, Dowrick A, Guymer RH, McCarty CA. "Iris colour, ethnic origin and progression of age-related macular degeneration. " Clin Experiment Ophthalmol. 2003 Dec;31(6):465-9. PMID 14641151.
  61. ^ Stang A, Ahrens W, Anastassiou G, Jockel KH. "Phenotypical characteristics, lifestyle, social class and uveal melanoma. " Ophthalmic Epidemiol. 2003 Dec;10(5):293-302. PMID 14566630.
  62. ^ [13]
  63. ^ eMedicine - Aniridia : Article by Daljit Singh
  64. ^ eMedicine - Ocular Manifestations of Albinism : Article by Mohammed O Peracha, MD
  65. ^ Imesch PD, Wallow IH, Albert DM. "The color of the human eye: a review of morphologic correlates and of some conditions that affect iridial pigmentation. " Surv Ophthalmol. 1997 Feb;41 Suppl 2:S117-23. PMID 9154287.
  66. ^ Hejkal TW, Camras CB (1999). "Prostaglandin analogs in the treatment of glaucoma". Seminars in ophthalmology 14 (3): 114-23. doi:10.153/SOPH01400114. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. PMID 10790575.  

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Iridology (also known as iridodiagnosis) is an Alternative medicine technique whose proponents believe that patterns colors and other characteristics of the Hair color is the pigmentation of hair follicles due to the two types of melanin Eumelanin and Phaeomelanin. Human skin color can range from almost black (due to very high concentrations of the dark brown pigment melanin to nearly colorless (appearing reddish white due to the Blood Chromatophores are pigment -containing and light-reflecting cells found in Amphibians Fish, Reptiles Crustaceans and Several inheritable traits or congenital conditions in humans are classical examples of Mendelian inheritance: Their presence is controlled by a single Gene that can either
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