color blindness color blindness color blindness or color vision deficiency (cvd) is the decreased ability to see color or differences in color. it can impair tasks such as selecting ripe fruit, choosing clothing, and reading traffic lights. color blindness may make some academic activities more difficult. however, issues are generally minor, and the colorblind automatically develop adaptations and coping mechanisms. people with total color blindness (achromatopsia) may also be uncomfortable in bright environments and have decreased visual acuity. color blindnessother namescolor vision deficiency, impaired color visionspecialtyophthalmologysymptomsdecreased ability to see colorsdurationlong termcausesgenetic (inherited usually x-linked)diagnostic methodishihara color testtreatmentadjustments to teaching methods, mobile appsfrequencyred–green: 8% males, 0.5% females (northern european descent) the most common cause of color blindness is an inherited problem or variation in the functionality of one or more of the three classes of cone cells in the retina, which mediate color vision. the most common form is caused by a genetic disorder called congenital red–green color blindness. males are more likely to be color blind than females, because the genes responsible for the most common forms of color blindness are on the x chromosome. non-color-blind females can carry genes for color blindness and pass them on to their children. color blindness can also result from physical or chemical damage to the eye, the optic nerve, or parts of the brain. screening for color blindness is typically done with the ishihara color test. there is no cure for color blindness. diagnosis may allow an individual, or their parents/teachers to actively accommodate the condition. special lenses such as enchroma glasses or x-chrom contact lenses may help people with red–green color blindness at some color tasks, but they do not grant the wearer "normal color vision". mobile apps can help people identify colors. red–green color blindness is the most common form, followed by blue–yellow color blindness and total color blindness. red–green color blindness affects up to 1 in 12 males (8%) and 1 in 200 females (0.5%). the ability to see color also decreases in old age. in certain countries, color blindness may make people ineligible for certain jobs, such as those of aircraft pilots, train drivers, crane operators, and people in the armed forces. the effect of color blindness on artistic ability is controversial, but a number of famous artists are believed to have been color blind. effects a colorblind subject will have decreased (or no) color discrimination along the red–green axis, blue–yellow axis, or both, though the vast majority of the colorblind are only affected on their red–green axis. the first indication of colorblindness generally consists of a person using the wrong color for an object, such as when painting, or calling a color by the wrong name. the colors that are confused are very consistent among people with the same type of color blindness. normal sight deuteranopia sight tritanopia sight monochromacy sight confusion colors confusion lines for the three types of dichromacy superimposed on ciexyz color space. confusion colors are pairs or groups of colors that will often be mistaken by the colorblind. confusion colors for red–green color blindness include: cyan and grey rose-pink and grey blue and purple yellow and neon green red, green, orange, brown confusion colors for blue–yellow color blindness include: yellow and grey blue and green dark blue/violet and black violet and yellow-green red and rose-pink these colors of confusion are defined quantitatively by straight confusion lines plotted in ciexyz, usually plotted on the corresponding chromaticity diagram. the lines all intersect at a copunctal point, which varies with the type of color blindness. chromaticities along a confusion line will appear metameric to dichromats of that type. anomalous trichromats of that type will see the chromaticities as metameric if they are close enough, depending on the strength of their cvd. for two colors on a confusion line to be metameric, the chromaticities first have to be made isoluminant, i.e. to have the same lightness. note also that colors that may be isoluminant to the standard observer (typical trichromat) may not be isoluminant to a dichromat. color tasks cole describes four color tasks, all of which are impeded to some degree by color blindness: comparative – when multiple colors must be compared, such as with mixing paint connotative – when colors are given an implicit meaning, such as red = stop denotative – when identifying colors, for example by name, such as "where is the yellow ball?" aesthetic – when colors look nice – or convey an emotional response – but don't carry explicit meaning the following sections describe specific color tasks with which the colorblind typically have difficulty. food simulation of the normal (above) and dichromatic (below) perception of red and green apples colorblindness causes difficulty with the connotative color tasks associated with selecting or preparing food, for example: selecting food for ripeness can be difficult. the green–yellow transition of bananas is particularly hard to identify. detecting bruises, mold or rot on some foods determining when meat is done by color distinguishing some varietals, such as a braeburn from a granny smith apple distinguishing colors associated with artificial flavors (e.g. jelly beans, sports drinks) skin color changes in skin color due to bruising, sunburn, rashes or even blushing are easily missed by those with red–green colorblindness. these discolorations are often linked to the blood oxygen saturation, which affects skin reflectance. traffic lights