Daltonisme (document en anglais)

Color blindness, or color vision deficiency, is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions. Color blindness affects a significant percentage of the population. This type of color blindness is usually a sex-linked condition. The genes that produce photopigments are carried on the X chromosome; if some of these genes are missing or damaged, color blindness will be expressed in males with a higher probability than in females because males only have one X chromosome (in females, a functional gene on only one of the two X chromosomes is sufficient to yield the needed photopigments).

Color blindness can also be produced by physical or chemical damage to the eye, the optic nerve, or parts of the brain. .

The English chemist John Dalton published the first scientific paper on this subject in 1798, "Extraordinary facts relating to the vision of colours", after the realization of his own color blindness. Because of Dalton's work, the general condition has been called daltonism, although in English this term is now used more narrowly for deuteranopia alone.

There is no cure for colour blindness, but some countries help people who are affected by this deficience, like this picture wich shows us traffic lights with specials shapes.

In the picture of the ishihara test, if you can read the correct number, you are not daltonist, but if you can't, it is possible for you to be coulour blindness.

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