"That's a great deal to make one word mean," Alice said in a thoughtful tone. "When I make a word do a lot of work like that," said Humpty Dumpty, "I always pay it extra."

Tuesday, 2 October 2012

Heterochromia

In anatomy, heterochromia refers to a difference in coloration, usually of the iris but also of hair or skin. Heterochromia is a result of the relative excess or lack of melanin (a pigment). It may be inherited, or caused by genetic mosaicism, disease, or injury.



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Heterochromia of the eye (heterochromia iridis or heterochromia iridum; the common wrong form "heterochromia iridium" is not correct Latin) 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.

Eye color, 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).[5] In humans, usually, an excess of melanin indicates hyperplasia of the iris tissues, whereas a lack of melanin indicates hypoplasia.  (definition from Wikipedia)  

1 comment:

  1. Interesting. I never knew the proper name for it, but there used to be a clerk at one of the stores I frequented that had one brown eye and one blue. Very disconcerting to talk to her at first, but after a time, one hardly noticed any more.

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