Hemosiderosis – long standing hyphema (blood in the anterior chamber) following blunt trauma to the eye may lead to iron deposition from blood products.Siderosis – iron deposition within ocular tissues due to a penetrating injury and a retained iron-containing, intraocular foreign body.Huskies are a breed known to have a high incidence of heterochromia.Īcquired heterochromia is usually due to injury, inflammation, the use of certain eyedrops that damage the iris, or tumors. Īn Alaskan husky sled dog with heterochromia. The affected sectors have been shown to have reduced numbers of melanocytes and decreased stromal pigmentation. Hirschsprung's disease – a bowel disorder associated with heterochromia in the form of a sector hypochromia.Piebaldism – similar to Waardenburg's syndrome, a rare disorder of melanocyte development characterized by a white forelock and multiple symmetrical hypopigmented or depigmented macules.A Japanese review of 11 children with albinism found that the condition was present. Waardenburg syndrome – a syndrome in which heterochromia is expressed as a bilateral iris hypochromia in some cases.Congenital Horner's syndrome – sometimes inherited, although usually acquired.It may affect an iris completely or only partially. The lighter eye is typically regarded as the affected eye as it usually shows iris hypoplasia. Simple heterochromia – a rare condition characterized by the absence of other ocular or systemic problems.Individual with Waardenburg Syndrome Type II exhibiting complete heterochromia iridum Sturge–Weber syndrome – a syndrome characterized by a port-wine stain nevus in the distribution of the trigeminal nerve, ipsilateral leptomeningeal angiomas with intracranial calcification and neurologic signs, and angioma of the choroid, often with secondary glaucoma.Pigment dispersion syndrome – 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.Oculodermal melanocytosis (nevus of Ota).Ocular melanosis – a condition characterized by increased pigmentation of the uveal tract, episclera, and anterior chamber angle.Lisch nodules – iris hamartomas seen in neurofibromatosis.Sometimes one eye may change color following disease or injury. Most cases of heterochromia are hereditary, or caused by genetic factors such as chimerism, and are entirely benign and unconnected to any pathology, however, some are associated with certain diseases and syndromes. ![]() ![]() 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 (due to mosaicism or congenital) or acquired, with mention as to whether the affected iris or portion of the iris is darker or lighter. Heterochromia is classified primarily by onset: as either genetic or acquired. Ĭongenital heterochromia: inherited in autosomal dominant fashion (from men or women) The term is derived from Ancient Greek: ἕτερος, héteros "different" and χρῶμα, chrôma "color". In humans, an increase of melanin production in the eyes indicates hyperplasia of the iris tissues, whereas a lack of melanin indicates hypoplasia. The affected eye may be hyperpigmented (hyperchromic) or hypopigmented (hypochromic). ![]() Though common in some breeds of cats, dogs, cattle and horses due to inbreeding, heterochromia is uncommon in humans, affecting fewer than 200,000 people in the United States, and is not associated with lack of genetic diversity. This is due to a mutation of the genes that determine melanin distribution at the 8-HTP pathway, which usually only become corrupted due to chromosomal homogeneity. Though multiple causes have been posited, the scientific consensus is that a lack of genetic diversity is the primary reason behind heterochromia, at least in domestic animals. In central heterochromia, there is a ring around the pupil or possibly spikes of different colors radiating from the pupil. In sectoral heterochromia, part of one iris is a different color from its remainder. In complete heterochromia, one iris is a different color from the other. Heterochromia of the eye is called heterochromia iridum or heterochromia iridis. It occurs in humans and certain breeds of domesticated animals. It may be inherited, or caused by genetic mosaicism, chimerism, disease, or injury. Heterochromia is determined by the production, delivery, and concentration of melanin (a pigment). The term is most often used to describe color differences of the iris, but can also be applied to color variation of hair or skin. Heterochromia is a variation in coloration. Iris implant surgery (controversial for cosmetic purposes) Different or partially different eye color
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