Heterochromia
Encyclopedia
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
ation, usually of the iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
but also of hair
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
or skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
. Heterochromia is a result of the relative excess or lack of melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
(a pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
). It may be inherited, or caused by genetic mosaicism, disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
or injury
Injury
-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...
.
Eye color
Eye color
Eye color is a polygenic phenotypic character and is determined by two distinct factors: the pigmentation of the eye's iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris....
, specifically the color of the irises, is determined primarily by the concentration and distribution of melanin. The affected eye may be hyperpigmented (hyperchromic) or hypopigmented (hypochromic). In humans, usually, an excess of melanin indicates hyperplasia
Hyperplasia
Hyperplasia means increase in number of cells/proliferation of cells. It may result in the gross enlargement of an organ and the term is sometimes mixed with benign neoplasia/ benign tumor....
of the iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
tissues, whereas a lack of melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
indicates hypoplasia.
Heterochromia of the eye
Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
(heterochromia iridis or heterochromia iridum; the common wrong form "heterochromia iridium" is not correct Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
) is of two kinds. In complete heterochromia, one iris is a different color from the other. In partial heterochromia or sectoral heterochromia, part of one iris is a different color from its remainder.
Classification
Heterochromia is classified primarily by onset: as either geneticGenetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
or acquired.
Although a distinction is frequently made between heterochromia that affects an eye completely or only partially (sectoral heterochromia), it is often classified as either genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
(due to mosaicism or congenital) or acquired, with mention as to whether the affected iris or portion of the iris is darker or lighter.
Congenital heterochromia
Heterochromia that is congenital is usually inherited as an autosomal dominant trait.Abnormal iris darker
- Lisch nodulesLisch nodulesA Lisch nodule is a pigmented hamartomatous nodular aggregate of dendritic melanocytes affecting the iris, named after Austrian ophthalmologist Karl Lisch , who first recognized them in 1937....
– iris hamartomaHamartomaA hamartoma is a benign, focal malformation that resembles a neoplasm in the tissue of its origin. This is not a malignant tumor, and it grows at the same rate as the surrounding tissues. It is composed of tissue elements normally found at that site, but which are growing in a disorganized mass...
s seen in neurofibromatosisNeurofibromatosisNeurofibromatosis is a genetically-inherited disorder in which the nerve tissue grows tumors that may be benign or may cause serious damage by compressing nerves and other tissues...
. - Ocular melanosisOcular melanosisOcular melanosis , also known as ocular melanocytosis or melanosis oculi, is a congenital disease of the eye which affects about 1 in every 5000 people and is a risk factor for uveal melanoma. In dogs is found almost exclusively in the Cairn Terrier, where until recently it was known as pigmentary...
– a condition characterized by increased pigmentation of the uveal tract, episcleraEpiscleraThe episclera is the outermost layer of the sclera. It is composed of loose, fibrous, elastic tissue and attaches to Tenon's capsule.A vascular plexus is found between the conjunctiva and the sclera consisting of two layers of vessels, the superficial episcleral vessels and the deep episcleral...
, and anterior chamber angle. - Oculodermal melanocytosis (nevus of Ota)
- Pigment dispersion syndromePigment dispersion syndromePigment dispersion syndrome is an affliction of the eye that can lead to a form of glaucoma known as pigmentary glaucoma. It takes place when pigment cells slough off from the back of the iris and float around in the aqueous humor...
– a condition characterized by loss of pigmentation from the posterior iris surface which is disseminated intraocularly and deposited on various intraocular structures, including the anterior surface of the iris. - Sturge-Weber syndromeSturge-Weber syndromeSturge–Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare congenital neurological and skin disorder. It is one of the phakomatoses and is often associated with port-wine stains of the face, glaucoma, seizures, mental retardation, and ipsilateral leptomeningeal...
– a syndrome characterized by a port-wine stainPort-wine stainA port-wine stain or naevus flammeus is a vascular anomaly consisting of superficial and deep dilated capillaries in the skin which produce a reddish to purplish discoloration of the skin. They are so called for their colour, resembling that of port wine...
nevus in the distribution of the trigeminal nerve, ipsilateral leptomeningeal angiomas (leptomaningiomas) with intracranial calcification and neurologic signs, and angioma of the choroid, often with secondary glaucoma.
Abnormal iris lighter
- Simple heterochromia – a rare condition characterized by the absence of other ocular or systemic problems. The lighter eye is typically regarded as the affected eye as it usually shows iris hypoplasiaHypoplasiaHypoplasia is underdevelopment or incomplete development of a tissue or organ. Although the term is not always used precisely, it properly refers to an inadequate or below-normal number of cells. Hypoplasia is similar to aplasia, but less severe. It is technically not the opposite of hyperplasia...
. It may affect an iris completely or only partially. - Congenital Horner's syndromeHorner's syndromeHorner's syndrome is the combination of drooping of the eyelid and constriction of the pupil , sometimes accompanied by decreased sweating of the face on the same side; redness of the conjunctiva of the eye is often also present...
– sometimes inherited, although usually acquired - Waardenburg's syndrome – a syndrome in which heterochromia is expressed as a bilateral iris hypochromia in some cases. A Japanese review of 11 albino children with the disorder found that all had sectoral/partial heterochromia.
- PiebaldismPiebaldismPiebaldism is a rare autosomal dominant disorder of melanocyte development. Common characteristics include a congenital white forelock, scattered normal pigmented and hypopigmented macules and a triangular shaped depigmented patch on the forehead....
– similar to Waardenburg's syndrome, a rare disorder of melanocyte development characterized by a white forelock and multiple symmetrical hypopigmented or depigmented macules. - Hirschsprung's diseaseHirschsprung's diseaseHirschsprung's disease , or congenital aganglionic megacolon is a serious medical problem where the enteric nervous system is missing from the end of the bowel. The enteric nervous system is a complex network of neurons and glia that controls most aspects of intestinal function...
– a bowel disorder associated with heterochromia in the form of a sector hypochromia. The affected sectors have been shown to have reduced numbers of melanocytes and decreased stromal pigmentation. - Incontinentia pigmentiIncontinentia pigmentiIncontinentia Pigmenti is a genetic disorder that affects the skin, hair, teeth, nails, and central nervous system...
- Parry-Romberg syndromeParry-Romberg syndromeParry–Romberg syndrome is a rare neurocutaneous syndrome characterized by progressive shrinkage and degeneration of the tissues beneath the skin, usually on only one side of the face but occasionally extending to other parts of the body...
Acquired heterochromia
Heterochromia that is acquired is usually due to injury, inflammation, the use of certain eyedrops, or tumors.Abnormal iris darker
- Deposition of material
- SiderosisSiderosisSiderosis is the deposition of iron in tissue.When used without qualification, it usually refers to an environmental disease of the lung.Also Siderosis Bulbi, deposition of iron into the eye causing injury as the material chemically reacts with tissues and cells.-Causative agent:Iron oxide present...
– iron deposition within ocular tissues due to a penetrating injury and a retained iron-containing, intraocular foreign body. - HemosiderosisHemosiderosisIdiopathic pulmonary haemosiderosis is a lung disease of unknown cause that is characterized by alveolar capillary bleeding and accumulation of haemosiderin in the lungs...
– long standing hyphema (blood in the anterior chamber) following blunt trauma to the eye may lead to iron deposition from blood products
- Siderosis
- Use of certain eyedrops – prostaglandin analoguesProstaglandinA prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring....
(latanoprostLatanoprostLatanoprost ophthalmic solution is a topical medication used for controlling the progression of glaucoma or ocular hypertension by reducing intraocular pressure...
, isopropyl unoprostone, travoprostTravoprostTravoprost ophthalmic solution is a topical medication used for controlling the progression of glaucoma or ocular hypertension, by reducing intraocular pressure. It is a synthetic prostaglandin analog that works by increasing the outflow of aqueous fluid from the eyes...
, and bimatoprostBimatoprostBimatoprost is a prostaglandin analog/prodrug used topically to control the progression of glaucoma and in the management of ocular hypertension. It reduces intraocular pressure by increasing the outflow of aqueous fluid from the eyes...
) are used topically to lower intraocular pressureIntraocular pressureIntraocular pressure is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk from glaucoma...
in glaucomaGlaucomaGlaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...
patients. A concentric heterochromia has developed in some patients applying these drugs. The stroma around the iris sphincter muscle becomes darker than the peripheral stroma. A stimulation of melanin synthesis within iris melanocytes has been postulated. - Neoplasm – Nevi and melanomatous tumors.
- Iridocorneal endothelium syndrome
- Iris ectropion syndrome
Abnormal iris lighter
- Fuchs heterochromic iridocyclitisFuchs heterochromic iridocyclitisFuchs heterochromic iridocyclitis is a chronic unilateral iridocyclitis appearing with the triad of heterochromia, predisposition to cataracts and glaucoma, and keratitic precipitates on the posterior corneal surface...
– a condition characterized by a low grade, asymptomatic uveitisUveitisUveitis specifically refers to inflammation of the middle layer of the eye, termed the "uvea" but in common usage may refer to any inflammatory process involving the interior of the eye....
in which the iris in the affected eye becomes hypochromic and has a washed-out, somewhat moth eaten appearance. The heterochromia can be very subtle, especially in patients with lighter colored irides. It is often most easily seen in daylight. The prevalence of heterochromia associated with Fuchs has been estimated in various studies with results suggesting that there is more difficulty recognizing iris color changes in dark-eyed individuals. - Acquired Horner's syndromeHorner's syndromeHorner's syndrome is the combination of drooping of the eyelid and constriction of the pupil , sometimes accompanied by decreased sweating of the face on the same side; redness of the conjunctiva of the eye is often also present...
– usually acquired, as in neuroblastomaNeuroblastomaNeuroblastoma is the most common extracranial solid cancer in childhood and the most common cancer in infancy, with an annual incidence of about 650 cases per year in the US , and 100 cases per year in the UK . Close to 50 percent of neuroblastoma cases occur in children younger than two years old...
, although sometimes inherited. - Neoplasm – MelanomaMelanomaMelanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
s can also be very lightly pigmented, and a lighter colored iris may be a rare manifestation of metastatic disease to the eye.
Heterochromia has also been observed in those with Duane syndrome
Duane syndrome
Duane syndrome is a rare, congenital eye movement disorder most commonly characterized by the inability of the eye to abduct or move outwards...
.
- Chronic iritisIritisIritis is a form of anterior uveitis and refers to the inflammation of the iris of the eye.-Types:There are two main types of iritis: acute and chronic. They differ in numerous ways....
- Juvenile xanthogranuloma
- LeukemiaLeukemiaLeukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...
and lymphomaLymphomaLymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...
Central heterochromia
Central heterochromia is an eye condition where there are two colors in the same irisIris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
; the central (pupillary) zone of the iris is a different color than the mid-peripheral (ciliary) zone.
Eye color
Eye color
Eye color is a polygenic phenotypic character and is determined by two distinct factors: the pigmentation of the eye's iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris....
is determined primarily by the concentration and distribution of melanin within the iris tissues; anything affecting those factors may result in a difference of color being observed.
The human iris can be seen in a number of various colors. There are three true colors in human eyes that determine the outward appearance: brown, yellow, and grey. The amount of each color an individual has determines the appearance of his or her eye color.
Eye
Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
s displaying central heterochromia are often referred to as "cat eyes" because of the appearance of a multi-colored iris. Central heterochromia appears to be prevalent in irises containing low amounts of melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
. A famous case of a person with central heterochromia was Baroness Rozsika Edle von Wertheimstein, whose daughter wrote: "She was a very beautiful woman... She had dark, dark brown eyes, but each eye had a purple ring to it, about a quarter of an inch of purple around these dark brown eyes."
Famous people with heterochromia iridum
In other organisms
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
, particularly breeds such as Turkish Van
Turkish Van
The Turkish Van is a recognized cat breed that is known for its unusual love of water and swimming. They were created from the cats native to the Lake Van area of Turkey. The cats of this type are named in Turkish Van Kedisi , in Armenian vana katou or vana gadou and in Kurdish...
, Turkish Angora
Turkish Angora
The Turkish Angora is a breed of domestic cat. Turkish Angoras are one of the ancient, naturally occurring cat breeds, having originated in central Turkey, in the Ankara region...
, Khao Manee
Khao Manee
The Khao Manee cat, also known as the Diamond Eye cat, is a rare breed of cat originating in Thailand, which has an ancient ancestry tracing back hundreds of years. They are mentioned in the Tamra Maew, or Cat Book Poems. Khao Manee cats are pure white with a short, smooth, close-lying coat. They...
and (rarely) Japanese Bobtail. These so-called odd-eyed cat
Odd-eyed cat
An odd-eyed cat is a cat with one blue eye and one green, yellow or brown eye. It is a feline form of complete heterochromia, a condition which occurs in some other animals...
s are white, or mostly white, with one normal eye (copper, orange, yellow, green), and one blue eye. Among dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s, complete heterochromia is seen often in the Siberian Husky
Siberian Husky
The Siberian Husky is a medium-size, dense-coat working dog breed that originated in north-eastern Siberia. The breed belongs to the Spitz genetic family...
and few other breeds, usually Australian Shepherd
Australian Shepherd
The Australian shepherd is a breed of herding dog that was developed on ranches in the Western United States. Despite its name, the breed, commonly known as an Aussie, did not originate in Australia They acquired their name because some of the Australian sheepdogs arrived in the United States with...
and Catahoula Leopard Dog. Horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s with complete heterochromia have one brown and one white, gray, or blue eye - complete heterochromia is more common in horses with pinto
Pinto horse
A pinto horse has a coat color that consists of large patches of white and any other color. The distinction between "pinto" and "solid" can be tenuous, as so-called "solid" horses frequently have areas of white hair. Various cultures throughout history appear to have selectively bred for pinto...
coloring. Complete heterochromia occurs also in cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
and even water buffalo. It can also be seen in ferrets with Waardenburg Syndrome
Waardenburg syndrome
Waardenburg syndrome Waardenburg syndrome Waardenburg syndrome (also Waardenburg Shah Syndrome, Waardenburg-Klein syndrome, Mende's syndrome II, Van der Hoeve-Halbertsma-Waardenburg syndrome, Ptosis-Epicanthus syndrome, Van der Hoeve-Halbertsma-Gualdi syndrome, Waardenburg type Pierpont,[5] Van...
, although it can be very hard to tell at times as the eye color is often a midnight blue.
Sectoral heterochromia, usually sectoral hypochromia, is often seen in dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s, specifically in breeds with merle
Merle (coat colour in dogs)
Merle is a pattern in a dogs coat, though is commonly incorrectly referred to as a color.- Description :Merle can affect all coat colors but the colors most commonly seen that are affected are brown and black, when affected by merle they are usually called liver and blue, though some call liver red...
coats. These breeds include the Australian Shepherd
Australian Shepherd
The Australian shepherd is a breed of herding dog that was developed on ranches in the Western United States. Despite its name, the breed, commonly known as an Aussie, did not originate in Australia They acquired their name because some of the Australian sheepdogs arrived in the United States with...
, Border Collie
Border Collie
The Border Collie is a herding dog breed developed in the Anglo-Scottish border region for herding livestock, especially sheep. It is the most widespread of the collie breeds....
, Collie
Collie
The collie is a distinctive type of herding dog, including many related landraces and formal breeds. It originates in Scotland and Northern England. It is a medium-sized, fairly lightly built dog with a pointed snout, and many types have a distinctive white pattern over the shoulders. Collies...
, Shetland Sheepdog
Shetland Sheepdog
The Shetland Sheepdog, often known as the Sheltie, is a breed of herding dog.They are small to medium dogs, and come in a variety of colors, such as sable/white, tri-color, and blue merle. They are vocal, excitable, energetic dogs who are always willing to please and work hard...
, Welsh Corgi
Welsh Corgi
The Welsh corgi is a small type of herding dog that originated in Wales. Two distinct breeds are recognized: the Pembroke Welsh corgi and the Cardigan Welsh corgi, with the Pembroke being the more common..-Description:...
, Pyrenean Shepherd
Pyrenean Shepherd
The Pyrenean Shepherd is a medium-small breed of dog native to the Pyrenees mountains in southern France and northern Spain, bred since at least medieval times for herding livestock, especially sheep...
, Mudi
Mudi
The Mudi is a rare herding breed of dog from Hungary.- Appearance :Mudis usually weigh and stand high at the withers. The coat is medium wavy or curly, with short hair on the face and legs. The accepted colors are black, ash, brown, white, fawn, and black merle...
, Beauceron
Beauceron
The Beauceron is a guard dog and herding dog breed falling into the working dog category whose origins lie in the plains of Northern France. The Beauceron is also known as Berger de Beauce or Bas Rouge .-Appearance:This breed stands 61 to 70 cm in height and weighs 30 to 45 kg The...
, Catahoula Cur, Dunker
Dunker
A Dunker is a breed of dog also known as the Norwegian Hound. It was bred by Wilhelm Dunker by crossing a Russian Harlequin Hound with dependable Norwegian scent hounds.-Appearance:Head: Is Elongated, but not wedge shaped and a moderate stop....
, Great Dane
Great Dane
The Great Dane , also known as German Mastiff or Danish Hound , is a breed of domestic dog known for its giant size...
, Dachshund
Dachshund
The dachshund is a short-legged, long-bodied dog breed belonging to the hound family. The standard size dachshund was bred to scent, chase, and flush out badgers and other burrow-dwelling animals, while the miniature dachshund was developed to hunt smaller prey such as rabbits...
and Chihuahua
Chihuahua (dog)
The ' is the smallest breed of dog and is so named for the state of Chihuahua in Mexico. Chihuahuas come in a wide variety of sizes, head shapes, colors and coat lengths.-History:...
. It also occurs in certain breeds that do not carry the merle trait, such as the Siberian Husky
Siberian Husky
The Siberian Husky is a medium-size, dense-coat working dog breed that originated in north-eastern Siberia. The breed belongs to the Spitz genetic family...
and Alaskan Malamute
Alaskan Malamute
The Alaskan Malamute is a generally large breed of domestic dog originally bred for use as a utilitarian dog and later an Alaskan sled dog. They are sometimes mistaken for a Siberian Husky, but in fact are quite different in many ways...
.
See also
- Chimera (genetics)Chimera (genetics)A chimera or chimaera is a single organism that is composed of two or more different populations of genetically distinct cells that originated from different zygotes involved in sexual reproduction. If the different cells have emerged from the same zygote, the organism is called a mosaic...
- List of people with heterochromia
- List of systemic diseases with ocular manifestations
- Brushfield spotsBrushfield spotsBrushfield spots are small white or grayish/brown spots on the periphery of the iris in the human eye due to aggregation of connective tissue, a normal iris element. The spots are named after the physician, Thomas Brushfield, who first described them in his 1924 M.D...