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Color blindness
Classification and external resources
ICD-10 H53.5
ICD-9 368.5
DiseasesDB 2999
MeSH D003117
.Color blindness or color vision deficiency is the inability to perceive differences between some of the colors that others can distinguish.^ The pieces are shaped differently so that one color can be distinguished from the other.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Offering color blind options on equipment is simple and does not interfere with other drivers' ability to drive.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ If you lie about a disability and you go in the Armed Forces and some how cannot tell the difference between you and the enemy, you deserve to die.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

.It is most often of genetic nature, but may also occur because of eye, nerve, or brain damage, or exposure to certain chemicals.^ Glaucoma, uveitis, cataract, and degenerative lesions of the eye may occur months to years after onset of the RLF stage.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ In any case, an abnormal proliferation of blood vessels in the eye occurs, and there may be subsequent development of scar tissue , with bleeding and detachment of the retina.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.The English chemist John Dalton published the first scientific paper on the subject in 1798, "Extraordinary facts relating to the vision of colours",[1] after the realization of his own color blindness.^ You will never be out fighting, in fact there is little you can do being color blind.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ Now let's say that 33% of those color blind gamers would have purchased at least one microtransaction in the first month.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ Is developing a color blind mode really that costly?
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

.Because of Dalton's work, the condition was often called daltonism, although this term is now used for a type of color blindness called deuteranopia.^ Color Blindness is hardly a "rare" condition.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ He worked with deaf-blind students and developed the basic methods of communication later used by Anne Sullivan in her work with Helen Keller.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ They do it because they believe blindness is a tragic condition for anyone.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Color blindness is sometimes classed as a disability, however, in certain situations color blind individuals have an advantage over those with normal color vision.^ In the video game world, it is a matter of a couple dozen lines of code, at most, to compensate for color blindness and put them on equal footing with those who do not have the disability.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ The only problem with your argument is that in real life battle situations, there is no compensating for color blindness.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ Kenneth Jernigan's writings and speeches on blindness are better known and have touched more lives than those of any other individual writing today.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.There are some studies which conclude that color blind individuals are better at penetrating certain color camouflages and it has been suggested that this may be the evolutionary explanation for the surprisingly high frequency of congenital red-green colour blindness.^ However, there may be someone who could offer her a ride to some of the activities in exchange for help with the gasoline purchase.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Some states have established independent living programs to provide services to older blind individuals.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ It would take about 5 minutes to make a mode that changes the colors from red and green to something that is more distinguishable to color blind people.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

[2]
An 1895 illustration of normal vision and various kinds of color blindness

Contents

Background

The average human retina contains two kinds of light cells: the rod cells (active in low light) and the cone cells (active in normal daylight). .Normally, there are three kinds of cones, each containing a different pigment, which are activated when the pigments absorb light.^ UniProtKB/Swiss-Prot: OPSB_HUMAN, P03999 Tissue specificity : The three color pigments are found in the cone photoreceptor cells .
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ Albinism is a hereditary condition in which there is a lack of normal pigment in part or all of the body.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ It encodes the blue cone pigment gene which is one of three types of cone photoreceptors responsible for normal color vision.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

.The technical names for these receptors are S-cones, M-cones, and L-cones, but they are also often referred to as blue cones, green cones, and red cones, respectively.^ We are talking about people who have a hard time telling green from red and getting confused in the middle of a game that they can otherwise play just fine.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ In multiplayer MW2 matches, the quickest way to tell a teammate from an enemy is if their name is in red (enemy) or green (teammate).
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ Basically what these petitioners are asking for is a way to change the Friend/Foe colors from Green/Red to Blue/Orange.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

The absorption spectra of the cones differ; one is maximally sensitive to short wavelengths, one to medium wavelengths, and the third to long wavelengths, with their peak sensitivities in the blue, yellowish-green, and yellow regions of the spectrum, respectively. The absorption spectra of all three systems cover much of the visible spectrum.
.Although these receptors are often referred to as "blue, green and red" receptors, this is not entirely accurate, especially as the "red" receptor actually has its peak sensitivity in the yellow region.^ Affected individuals lack blue and yellow sensory mechanisms while retaining those for red and green.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ Basically what these petitioners are asking for is a way to change the Friend/Foe colors from Green/Red to Blue/Orange.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ (PubMed id 1531728) 3, 4, 6 Weitz C.J....Nathans J. (1992) Molecular genetics of human color vision: the genes encoding blue, green, and red pigments.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

.The sensitivity of normal color vision actually depends on the overlap between the absorption spectra of the three systems: different colors are recognized when the different types of cone are stimulated to different degrees.^ UniProtKB/Swiss-Prot: OPSB_HUMAN, P03999 Tissue specificity : The three color pigments are found in the cone photoreceptor cells .
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ (PubMed id 3303660) 3, 4 Applebury M.L. and Hargrave P.A. (1986) A novel mutation in the short-wavelength-sensitive cone pigment gene associated with a tritan color vision defect.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ It encodes the blue cone pigment gene which is one of three types of cone photoreceptors responsible for normal color vision.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

.Red light, for example, stimulates the long wavelength cones much more than either of the others, and reducing the wavelength causes the other two cone systems to be increasingly stimulated, causing a gradual change in hue.^ He hasn't change much other than the names of people he attacks.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ One will hurt our cause as much as the other.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ That narrative is much more than a success story.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Many of the genes involved in color vision are on the X chromosome, making color blindness more common in males than in females.^ The petition cites statistics that 8.0% of all males are color blind and 0.5% of females.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ It encodes the blue cone pigment gene which is one of three types of cone photoreceptors responsible for normal color vision.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ It could come in many forms, leaving a person seeing only black/white, or making the distinction between different colors impossible for the person.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

Causes

.Any recessive genetic characteristic that persists at a level as high as 5% is generally regarded as possibly having some advantage over the long term[citation needed].^ The likelihood of regaining useful sight is generally good, with some estimates placing it as high as 95%, although complications may prevent successful treatment in some cases.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Some have found the pattern of inheritance for this recessive characteristic confusing.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.At one time the U.S. Army found that color blind persons could spot "camouflage" colors that fooled those with normal color vision.^ It encodes the blue cone pigment gene which is one of three types of cone photoreceptors responsible for normal color vision.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ It could come in many forms, leaving a person seeing only black/white, or making the distinction between different colors impossible for the person.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ In the main he employs alternative techniques to do those things which he would do with sight if he had normal vision that is, he does if he functions efficiently.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

[3] .Humans are the only trichromatic primates with such a high percentage of color blindness.^ Color blindness is an issue with a large protion of the human population as pointed out in the article.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The only problem with your argument is that in real life battle situations, there is no compensating for color blindness.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

[4]
Another possible advantage might result from the presence of a tetrachromic female. Owing to X-chromosome inactivation, women who are heterozygous for anomalous trichromacy ought to have at least four types of cone in their retinae. It is possible that this affords them an extra dimension of color vision, by analogy to New World monkeys where heterozygous females gain trichromacy in a basically dichromatic species.[5]

Genetic modes of inheritance

Color blindness can be inherited genetically. .It is most commonly inherited from mutations on the X chromosome but the mapping of the human genome has shown there are many causative mutations – mutations capable of causing color blindness originate from at least 19 different chromosomes and 56 different genes (as shown online at the Online Mendelian Inheritance in Man (OMIM) database at Johns Hopkins University).^ Defects in this gene are the cause of tritan color blindness (tritanopia).
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ Mutations of the color pigment genes .
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ OMIM: 190900 UniProtKB/Swiss-Prot: OPSB_HUMAN, P03999 Defects in OPN1SW are the cause of tritan color blindness (tritanopia) [MIM:190900] Human Gene Mutation Database : OPN1SW Genetic Association Database: OPN1SW .
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

Some of the inherited diseases known to cause color blindness are:
Inherited color blindness can be congenital (from birth), or it can commence in childhood or adulthood. Depending on the mutation, it can be stationary, that is, remain the same throughout a person's lifetime, or progressive. .As progressive phenotypes involve deterioration of the retina and other parts of the eye, certain forms of color blindness can progress to legal blindness, i.e., an acuity of 6/60 or worse, and often leave a person with complete blindness.^ This condition can affect other parts of the eyecornea, retina, sclera, for example and may be serious enough to lead to loss of vision.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The visual loss is progressive, so that the individual usually becomes legally blind by young adulthood and slowly loses more and more vision thereafter.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ It is greatly different from surrounding tissue, grows rapidly without stopping, and often spreads through the lymph system to sprout growths in other parts of the body.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Color blindness always pertains to the cone photoreceptors in retinas, as the cones are capable of detecting the color frequencies of light.^ Of course these can vary from country to country and a color blind person would be responsible for learning the traffic light layout for the country they are driving in.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ Multiplayer balance is always a big deal for developers, wouldn't allowing for a simple font color change level the playing field for color blinded players?
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

.About 8 percent of males, but only 0.5 percent of females, are color blind in some way or another, whether it is one color, a color combination, or another mutation.^ The petition cites statistics that 8.0% of all males are color blind and 0.5% of females.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ It would take about 5 minutes to make a mode that changes the colors from red and green to something that is more distinguishable to color blind people.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ And don't tell me its about the money because he makes way too much now to need the headache of an NFL team, especially one that is losing.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

[6][7] .The reason males are at a greater risk of inheriting an X linked mutation is because males only have one X chromosome (XY, with the Y chromosome being significantly shorter than the X chromosome), and females have two (XX); if a woman inherits a normal X chromosome in addition to the one which carries the mutation, she will not display the mutation.^ This familiar condition is predominant in males (in about 8% as opposed to around 0.5% of females) and most commonly is a sex-linked inherited characteristic transmitted through the male chromosome, although it may also result from poisoning or retinal disease.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ This is likely to happen if the two eyes focus differently because of strabismus (see below) or because one eye is much more nearsighted than the other.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

Men do not have a second X chromosome to override the chromosome which carries the mutation. If 5% of variants of a given gene are defective, the probability of a single copy being defective is 5%, but the probability that two copies are both defective is 0.05 × 0.05 = 0.0025, or just 0.25%.

Other causes

.Other causes of color blindness include brain or retinal damage caused by shaken baby syndrome, accidents and other trauma which produce swelling of the brain in the occipital lobe, and damage to the retina caused by exposure to ultraviolet light.^ Offering color blind options on equipment is simple and does not interfere with other drivers' ability to drive.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ She became deaf and blind at the age of 19 months through a damaging brain fever.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Most ultraviolet light damage is caused during childhood and this form of retinal degeneration is the leading cause of blindness in the world.^ In the video game world, it is a matter of a couple dozen lines of code, at most, to compensate for color blindness and put them on equal footing with those who do not have the disability.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ Various forms of cataract make up one of the leading causes of blindness in this country today.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Corneal ulcers Scarring or perforation due to corneal ulceration is a major cause of blindness throughout the world.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.October 2009" style="white-space:nowrap;">[citation needed] Damage often presents itself later on in life.^ Reply Report Abuse by edrossinoelwein9669 ( October 15, 2009 4:25 pm ET ) 1 I guess Bill Clinton and Al Gore aren't white men.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ Reply Report Abuse by skatscan5624 ( October 15, 2009 10:45 am ET ) Yeah, Don't look at the mainstream media of the present to get the misinformation.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

.Color blindness may also present itself in the spectrum of degenerative diseases of the eye, such as age-related macular degeneration, and as part of the retinal damage caused by diabetes.^ Complications such as retinal detachment, cataracts, or secondary glaucoma may appear with degenerative myopia.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Glaucoma, uveitis, cataract, and degenerative lesions of the eye may occur months to years after onset of the RLF stage.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Such a tumor may be removed surgically, and in many cases the eye recovers to become completely normal.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

Types

.There are many types of color blindness.^ How many animals are color blind?
  • WikiAnswers - What animals are color blind 10 February 2010 13:37 UTC wiki.answers.com [Source type: General]

^ There are two major types of color blindness.
  • Accommodating Color Blindness 10 February 2010 13:36 UTC www.stcsig.org [Source type: FILTERED WITH BAYES]

^ There are many great resources on the Internet that cover color blindness.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

.The most common are red-green hereditary photoreceptor disorders, but it is also possible to acquire color blindness through damage to the retina, optic nerve, or higher brain areas.^ Techniques and instruments have been developed that make it possible for blind individuals to do most activities for which sight is ordinarily considered necessary.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ In the video game world, it is a matter of a couple dozen lines of code, at most, to compensate for color blindness and put them on equal footing with those who do not have the disability.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ It would take about 5 minutes to make a mode that changes the colors from red and green to something that is more distinguishable to color blind people.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

Higher brain areas implicated in color processing include the parvocellular pathway of the lateral geniculate nucleus of the thalamus, and visual area V4 of the visual cortex. .Acquired color blindness is generally unlike the more typical genetic disorders.^ More on color blindness.
  • Color Blindness 10 February 2010 13:36 UTC www.halifaxhealth.org [Source type: General]
  • Your Health - Color Blindness 10 February 2010 13:36 UTC www.aurorahealthcare.org [Source type: General]
  • Color Blindness - Content Viewer 10 February 2010 13:36 UTC www.svmh.com [Source type: General]
  • St. David's HealthCare - Health Information - Color Blindness 10 February 2010 13:36 UTC stdavids.com [Source type: General]
  • Tufts Medical Center - Color Blindness 10 February 2010 13:36 UTC www.tufts-nemc.org [Source type: FILTERED WITH BAYES]
  • Color blindness - Beth Israel Deaconess Medical Center 10 February 2010 13:36 UTC www.bidmc.org [Source type: General]
  • healthelinks :: Consumer Health 10 February 2010 13:36 UTC healthlibrary.epnet.com [Source type: General]

^ More common is partial color blindness.
  • Homeopathy Forums - colour blindness! 10 February 2010 13:36 UTC www.hpathy.com [Source type: General]

^ Color blindness is sometimes acquired.
  • Color Blindness - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis 10 February 2010 13:36 UTC health.stateuniversity.com [Source type: FILTERED WITH BAYES]

.For example, it is possible to acquire color blindness only in a portion of the visual field but maintain normal color vision elsewhere.^ Only 1% of Eskimo males are color blind.
  • Color Blindness - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis 10 February 2010 13:36 UTC health.stateuniversity.com [Source type: FILTERED WITH BAYES]

^ Color blindness is not a total loss of color vision.

^ Why are only boys color blind?
  • WikiAnswers - Are cats colorblind 10 February 2010 13:37 UTC wiki.answers.com [Source type: General]

.Some forms of acquired color blindness are reversible.^ Some animals are color blind...
  • WikiAnswers - What animals are color blind 10 February 2010 13:37 UTC wiki.answers.com [Source type: General]

^ Yes, I too have some color blindness.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ But some people really are color-blind.
  • What's Color Blindness? - The Children's Hospital-Denver Area, Colorado, Rocky Mountain Region 10 February 2010 13:36 UTC www.thechildrenshospital.org [Source type: General]
  • What's Color Blindness? 2004-09-01 00:00:00.0 10 February 2010 13:36 UTC www.devoschildrens.org [Source type: General]

.Transient color blindness also occurs (very rarely) in the aura of some migraine sufferers.^ Color Blindness is hardly a "rare" condition.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ Some blind people prefer to wear primarily one color of socks, all black, all white, all blue.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ It was possible for blind persons to take some tests to qualify for employment with the federal government, and a few but a very few were beginning to be hired.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

[citation needed]
.The different kinds of inherited color blindness result from partial or complete loss of function of one or more of the different cone systems.^ More on color blindness.
  • Color Blindness 10 February 2010 13:36 UTC www.halifaxhealth.org [Source type: General]
  • Color Blindness ; Seattle Washington WA 10 February 2010 13:36 UTC www.swedish.org [Source type: General]
  • Your Health - Color Blindness 10 February 2010 13:36 UTC www.aurorahealthcare.org [Source type: General]
  • Color Blindness - Content Viewer 10 February 2010 13:36 UTC www.svmh.com [Source type: General]
  • Health Encyclopedia | Kent Hospital Warwick, RI 10 February 2010 13:36 UTC www.kenthospital.org [Source type: General]
  • healthelinks :: Consumer Health 10 February 2010 13:36 UTC healthlibrary.epnet.com [Source type: General]
  • Color Blindness (Color Vision Problem, Color Vision Deficiency) | ThirdAge Articles 10 February 2010 13:36 UTC www.thirdage.com [Source type: General]

^ Color blindness can be one symptom of this condition.
  • How Color Blindness Affects Your Daily Life - AllAboutVision.com 10 February 2010 13:36 UTC www.allaboutvision.com [Source type: FILTERED WITH BAYES]

^ Color blindness is not a total loss of color vision.

When one cone system is compromised, dichromacy results. .The most frequent forms of human color blindness result from problems with either the middle or long wavelength sensitive cone systems, and involve difficulties in discriminating reds, yellows, and greens from one another.^ This is fairly rare, but can also result in a female with multiple forms of red-green color deficiencies.
  • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

^ Q/Why_are_people_color_blind What is red green color blindness ?
  • Questions about Color Blindness - Ask.com 10 February 2010 13:36 UTC www.ask.com [Source type: General]

^ Dogs most definately are not color blind.
  • WikiAnswers - What animals are color blind 10 February 2010 13:37 UTC wiki.answers.com [Source type: General]

.They are collectively referred to as "red-green color blindness", though the term is an over-simplification and is somewhat misleading.^ They are color blind?
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ We are talking about people who have a hard time telling green from red and getting confused in the middle of a game that they can otherwise play just fine.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ If they try to sneak someone in or rush someone in with color blindness and something happens in training when they eventually go to their school for their MOS that recruiter is going to have a lot of problems.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

.Other forms of color blindness are much more rare.^ I’m color blind, which for a girl is very rare.
  • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

^ And we will be writing more color-blind romances.
  • romance fiction reviews, commentary, romantic movie reviews | MyRomanceStory Blog: Color-blind Romance 10 February 2010 13:37 UTC www.myromancestory.com [Source type: General]

^ Color blindness more prevalent in men: .
  • Tests To Detect Your Color Blindness! | Health Watch Center 10 February 2010 13:36 UTC www.healthwatchcenter.com [Source type: General]

.They include problems in discriminating blues from yellows, and the rarest forms of all, complete color blindness or monochromacy, where one cannot distinguish any color from grey, as in a black-and-white movie or photograph.^ Some blind people prefer to wear primarily one color of socks, all black, all white, all blue.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ They are color blind?
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

^ If they try to sneak someone in or rush someone in with color blindness and something happens in training when they eventually go to their school for their MOS that recruiter is going to have a lot of problems.
  • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

Classification of color deficiencies

By cause

The colors of the rainbow as viewed by a person with no color vision deficiencies.
The colors of the rainbow as viewed by a person with protanopia.
The colors of the rainbow as viewed by a person with deuteranopia.
The colors of the rainbow as viewed by a person with tritanopia.
Color vision deficiencies can be classified as acquired or inherited.[8][9]
  • Acquired
  • Inherited: .There are three types of inherited or congenital color vision deficiencies: monochromacy, dichromacy, and anomalous trichromacy.^ There are two types of anomalous Trichromacy: protanomaly and deuteranomaly.
    • Blindness Color Information, Types of Color Blindness 10 February 2010 13:36 UTC eye.ultimate-cosmetics.com [Source type: Original source]

    ^ What are the types of inherited color vision defects?
    • Color Blindness 10 February 2010 13:36 UTC www.uic.edu [Source type: FILTERED WITH BAYES]

    ^ An abnormality, or deficiency, of any of the types of cones will result in abnormal color vision.
    • Color Blindness - symptoms, average, Definition, Description, Demographics, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention 10 February 2010 13:36 UTC www.healthofchildren.com [Source type: Academic]
    • Color Blindness - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis 10 February 2010 13:36 UTC health.stateuniversity.com [Source type: FILTERED WITH BAYES]

    [8]
    .
  • Monochromacy, also known as "total color blindness,"[10] is the lack of ability to distinguish colors; caused by cone defect or absence.^ Offering color blind options on equipment is simple and does not interfere with other drivers' ability to drive.
    • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

    ^ It would take about 5 minutes to make a mode that changes the colors from red and green to something that is more distinguishable to color blind people.
    • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

    ^ In any event, use of various charts to test for color blindness is commonly included as part of an eye examination, especially for drivers and workers in industry and transportation, where the ability to distinguish colored signals is important.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    [11] .Monochromacy occurs when two or all three of the cone pigments are missing and color and lightness vision is reduced to one dimension.^ Anomalous Trichromat Vision Anomalous Trichromat vision, uses three color receptors but one pigment is misaligned .
    • How to Design Web Accessible Pages for the ColorBlind : Web Design Resources Blog & Graphics Blog with Lists of Web Site Design Tools 10 February 2010 13:36 UTC www.allwebdesignresources.com [Source type: General]

    ^ Dichromacy occurs when one of the cone pigments is missing and color is reduced to two dimensions.
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ The cones are responsible for the wonder of color vision.
    • Color Blindness - DrGreene.com 10 February 2010 13:36 UTC www.drgreene.com [Source type: General]

    [10]
  • Rod monochromacy (achromatopsia) is an exceedingly rare, nonprogressive inability to distinguish any colors as a result of absent or nonfunctioning retinal cones. .It is associated with light sensitivity (photophobia), involuntary eye oscillations (nystagmus), and poor vision.^ The exact cause of nystagmus is not fully understood, but it seems to be associated with poor vision in a kind of "vicious cycle" that is, nystagmus makes it more difficult to see, while at the same time poor vision increases the likelihood of nystagmus.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ Next, let us consider the person who has normal visual acuity but cannot hold his eyes open because of his sensitivity to light.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ The person with albinism usually has poor vision, an imperfectly developed retina, oversensitivity to light, and nystagmus (abnormal muscle movement causing constant twitching or jerking of the eyes).
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    [11]
  • .
  • Cone monochromacy is a rare total color blindness that is accompanied by relatively normal vision, electoretinogram, and electrooculogram.^ Color Blindness is hardly a "rare" condition.
    • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

    ^ If the pressure is not controlled, the delicate structure of the eye is increasingly damaged, resulting in blurred vision, a narrowed field of sight, and eventually total blindness.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ In my way of thinking it is this: One is blind to the extent that he must devise alternative techniques to do efficiently those things which he would do with sight if he had normal vision.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    [11]
.
  • Dichromacy is a moderately severe color vision defect in which one of the three basic color mechanisms is absent or not functioning.^ One of the most familiar tests consists of a circle containing dots of different colors, in which the subject with normal color vision is supposed to discern one number, while a person with defective color vision is likely to see another.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    It is hereditary and, in the case of Protanopia or Deuteranopia, sex-linked, affecting predominantly males.[11] .Dichromacy occurs when one of the cone pigments is missing and color is reduced to two dimensions.^ Dichromacy occurs when one of the cone pigments is missing and color is reduced to two dimensions.
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ Monochromacy occurs when two or all three of the cone pigments are missing and color and lightness vision is reduced to one dimension.
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ Color vision deficiency seems to occur in about 8% - 12% of males of European origin and about one-half of 1% of females.

    [10]
    .
  • Protanopia is a severe type of color vision deficiency caused by the complete absence of red retinal photoreceptors.^ It depends on the color vision deficiency, and the degree of severity.
    • Color blindness test 10 February 2010 13:36 UTC www.archimedes-lab.org [Source type: General]
    • Suzette » Can colorblind Ian enjoy 3D? 10 February 2010 13:37 UTC www.thesuzette.com [Source type: General]

    ^ With this test is not only possible to check the type of your color vision deficiency but also its severity.
    • Color Blindness Tests 10 February 2010 13:36 UTC www.colblindor.com [Source type: Original source]

    ^ Poor color vision has several causes.
    • For People With Color Vision Deficiency 10 February 2010 13:37 UTC www.colorblindclub.com [Source type: FILTERED WITH BAYES]

    .It is a form of dichromatism in which red appears dark.^ It is a form of dichromatism in which red appears dark.
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ He complained specifically about red links appearing to him indiscernible from black or dark gray text.
    • Testing designs for color-blindness – Jeffrey Zeldman Presents The Daily Report 10 February 2010 13:36 UTC www.zeldman.com [Source type: General]

    ^ The reduced intensity effect can result in red traffic lights appearing to not be lit, and red hues (in general), appearing as black or dark gray.
    • Molecular Expressions Microscopy Primer: Physics of Light and Color - Ishihara Colorblindness Test: Interactive Java Tutorial 10 February 2010 13:36 UTC micro.magnet.fsu.edu [Source type: FILTERED WITH BAYES]
    • Olympus Microscopy Resource Center: Physics of Light and Color - Ishihara Colorblindness Test: Interactive Java Tutorial 10 February 2010 13:36 UTC www.olympusmicro.com [Source type: FILTERED WITH BAYES]

    It is hereditary, sex-linked, and present in 1% of males.[11]
  • .
  • Deuteranopia is a color vision deficiency in which the green retinal photoreceptors are absent, moderately affecting red-green hue discrimination.^ Affected individuals lack blue and yellow sensory mechanisms while retaining those for red and green.
    • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

    ^ It would take about 5 minutes to make a mode that changes the colors from red and green to something that is more distinguishable to color blind people.
    • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

    ^ It encodes the blue cone pigment gene which is one of three types of cone photoreceptors responsible for normal color vision.
    • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

    .It is a form of dichromatism in which there are only two cone pigments present.^ There are two forms of diabetic retinopathy.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ It is a form of dichromatism in which there are only two cone pigments present.
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ Matt Says: October 28th, 2006 at 11:29 pm I’m sure there is a fix, it has to do with how the cones in your eyes form during childhood.
    • //toid.net » Blog Archive » Colorblind Test 10 February 2010 13:37 UTC toid.net [Source type: FILTERED WITH BAYES]

    .It is likewise hereditary and sex-linked.
  • Tritanopia is a very rare color vision disturbance in which there are only two cone pigments present and a total absence of blue retinal receptors.^ Many adults with retinitis pigmentosa have a very tiny field of vision in which they see well under a good light but which is so small as to be of little use.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ The exact mechanism of color blindness has not been fully explained, but some writers simply attribute it to an absence of one or more of the cone pigments or an abnormal presence of a mixture of two of the color-sensitive pigments in one cone.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ The only problem with your argument is that in real life battle situations, there is no compensating for color blindness.
    • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

    [11]
.
  • Anomalous trichromacy is a common type of inherited color vision deficiency, occurring when one of the three cone pigments is altered in its spectral sensitivity.^ It encodes the blue cone pigment gene which is one of three types of cone photoreceptors responsible for normal color vision.
    • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

    ^ UniProtKB/Swiss-Prot: OPSB_HUMAN, P03999 Tissue specificity : The three color pigments are found in the cone photoreceptor cells .
    • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

    ^ (PubMed id 3303660) 3, 4 Applebury M.L. and Hargrave P.A. (1986) A novel mutation in the short-wavelength-sensitive cone pigment gene associated with a tritan color vision defect.
    • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

    .This results in an impairment, rather than loss, of trichromacy (normal three-dimensional color vision).^ Colorblindness is not a total loss of color vision.
    • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

    ^ This results in an impairment, rather than loss, of trichromacy (normal three-dimensional color vision) .
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ Red letters (normal color vision)   .
    • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

    [10]
    .
  • Protanomaly is a mild color vision defect in which an altered spectral sensitivity of red retinal receptors (closer to green receptor response) results in poor red-green hue discrimination.^ Protanomaly : reduced red sensitivity.
    • Color Blindness 10 February 2010 13:36 UTC beercolor.com [Source type: FILTERED WITH BAYES]

    ^ The cones are responsible for the wonder of color vision.
    • Color Blindness - DrGreene.com 10 February 2010 13:36 UTC www.drgreene.com [Source type: General]

    ^ Individuals with red-green defects confuse colors from red through yellow to green.
    • Internetworking (2.1): Accessiblity-Designing for the Color-Challenged 10 February 2010 13:36 UTC www.internettg.org [Source type: Academic]

    It is hereditary, sex-linked, and present in 1% of males.[11]
  • .
  • Deuteranomaly, caused by a similar shift in the green retinal receptors, is by far the most common type of color vision deficiency, mildly affecting red-green hue discrimination in 5% of males.^ It would take about 5 minutes to make a mode that changes the colors from red and green to something that is more distinguishable to color blind people.
    • MW2 Patch for Color Blind Gamers Urged | GamePolitics 10 February 2010 13:37 UTC gamepolitics.com [Source type: General]

    ^ Generally affecting both eyes, it most often takes the form of a loss of perception of one or two fundamental colors (red-green color blindness is the most common congenital variety), but occasionally it is complete, so that the individual literally sees only in black and white.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ The most common is melanoma, a malignant spot of color.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .It is hereditary and sex-linked.^ It is hereditary and sex-linked.
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ It is likewise hereditary, sex-linked, and present in 1% of all males.
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    ^ It is hereditary and sex-linked, affecting predominantly males.
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:37 UTC www.creativepro.com [Source type: General]

    [11]
  • .
  • Tritanomaly is a rare, hereditary color vision deficiency affecting blue-yellow hue discrimination.^ Are goldfish color vision deficient?

    ^ No; diseases can also affect color vision.
    • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

    ^ Color vision of the blue-yellow colorblind (tritanopes) .
    • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]
    • Topics 10 February 2010 13:37 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

    Unlike most other forms, it is not sex-linked.[11]

By clinical appearance

.Based on clinical appearance, color blindness may be described as total or partial.^ Color-based distinctions may not be visible to people who are color blind.
  • Color Vision Confusion 10 February 2010 13:36 UTC otal.umd.edu [Source type: FILTERED WITH BAYES]

^ Total color-blindness is very rare.
  • Color Blind Modern Warfare Players Petition for Patch | GameLife | Wired.com 10 February 2010 13:37 UTC www.wired.com [Source type: General]

^ Clinical information about color blindness: .
  • About Color Blindness - What, why, how - problems 10 February 2010 13:36 UTC www.toledo-bend.com [Source type: FILTERED WITH BAYES]

.Total color blindness is much less common than partial color blindness.^ The  total-color-blind can hardly read it.
  • http://home.wanadoo.nl/paulschils/05.03.html 10 February 2010 13:36 UTC home.wanadoo.nl [Source type: FILTERED WITH BAYES]

^ Color blindness is not a total loss of color vision.

^ It is extremely rare to be totally color blind.
  • About Color Blindness - What, why, how - problems 10 February 2010 13:36 UTC www.toledo-bend.com [Source type: FILTERED WITH BAYES]

[12] .There are two major types of color blindness: those who have difficulty distinguishing between red and green, and those who have difficulty distinguishing between blue and yellow.^ Protanopia —The inability of difficulty in distinguishing blue and yellow colors.
  • Color Blindness - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis 10 February 2010 13:36 UTC health.stateuniversity.com [Source type: FILTERED WITH BAYES]

^ I'm red green deficient but I'm not sure which of those I am.
  • Color blindness - What things look like to color blind people. 10 February 2010 13:36 UTC digg.com [Source type: General]

^ Furthermore, it is proved that the red-green color blindness are red and green yellow, orange and beige.
  • Color blindness "Visual impairment" Documents on Web Accessibility "ideos, all digital 10 February 2010 13:36 UTC www.ideose.eu [Source type: FILTERED WITH BAYES]

[13][14]
  • Total color blindness
  • Partial color blindness
  • Red-green
  • Dichromacy (protanopia and deuteranopia)
  • Anomalous trichromacy (protanomaly and deuteranomaly)
  • Blue-yellow
  • Dichromacy (tritanopia)
  • Anomalous trichromacy (tritanomaly)

Congenital color vision deficiencies

.Congenital color vision deficiencies are subdivided based on the number of primary hues needed to match a given sample in the visible spectrum.^ Those with color vision deficiencies should not be  able to read this number or will read incorrectly.
  • http://home.wanadoo.nl/paulschils/05.03.html 10 February 2010 13:36 UTC home.wanadoo.nl [Source type: FILTERED WITH BAYES]

^ Those with color vision deficiencies will not read the number or read it incorrectly.
  • Colour blindness test. - TeakDoor.com - The Thailand Forum 10 February 2010 13:36 UTC teakdoor.com [Source type: General]

^ Those with color vision deficiencies will not read this number or read it incorrectly.
  • Colour blindness test. - TeakDoor.com - The Thailand Forum 10 February 2010 13:36 UTC teakdoor.com [Source type: General]

Monochromacy

.Monochromacy is the condition of possessing only a single channel for conveying information about color.^ Avoid the situation where important information is conveyed only in the form of color.
  • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]
  • Topics 10 February 2010 13:37 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

^ Eye information about Color Blindness .
  • Color Blindness | Eye information about Color Blindness 10 February 2010 13:36 UTC www.empowereddoctor.com [Source type: General]
  • Color Blindness | Eye information about Color Blindness 10 February 2010 13:36 UTC suntimes.empowereddoctor.com [Source type: General]

^ Do not convey information in color only.
  • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]
  • Topics 10 February 2010 13:37 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

[15] .Monochromats possess a complete inability to distinguish any colors and perceive only variations in brightness.^ It uses not only colors but also various hatching.
  • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]
  • Topics 10 February 2010 13:37 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

^ Monochromats cannot discriminate colors and perceive only shades of gray.
  • Internetworking (2.1): Accessiblity-Designing for the Color-Challenged 10 February 2010 13:36 UTC www.internettg.org [Source type: Academic]

^ Achromatopsia —The inability to distinguish any colors.
  • Color Blindness - symptoms, average, Definition, Description, Demographics, Causes and symptoms, Diagnosis, Treatment, Prognosis, Prevention 10 February 2010 13:36 UTC www.healthofchildren.com [Source type: Academic]
  • Color Blindness - Definition, Description, Causes and symptoms, Diagnosis, Treatment, Prognosis 10 February 2010 13:36 UTC health.stateuniversity.com [Source type: FILTERED WITH BAYES]

[15] It occurs in two primary forms:
.
  1. Rod monochromacy, frequently called achromatopsia, where the retina contains no cone cells, so that in addition to the absence of color discrimination, vision in lights of normal intensity is difficult.^ It then hits color sensitive cells called cones in the retina at the back of the eye.

    ^ Human color vision relies on special cells in the retina of the eye called cones .
    • The science and mathematics of color 10 February 2010 13:36 UTC www.inform.umd.edu [Source type: General]

    ^ Color blindness is also called a color vision problem.
    • CIGNA - Color Blindness 10 February 2010 13:36 UTC www.cigna.com [Source type: FILTERED WITH BAYES]

    .While normally rare, achromatopsia is very common on the island of Pingelap, a part of the Pohnpei state, Federated States of Micronesia, where it is called maskun: about 10% of the population there has it, and 30% are unaffected carriers.^ I have been called a racist several times on this very thread, and I have said nothing that should be construed as stating or implying the superiority of any race.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    ^ Although there are in the United States at the present time many organizations and agencies for the blind, there is only one National Federation of the blind.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ Though still common in many less developed countries, it has become rare in the United States.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .The island was devastated by a storm in the 18th century, and one of the few male survivors carried a gene for achromatopsia; the population is now several thousand.^ Moreover, the female with only one abnormal gene inherited from her father can become a "carrier" and pass the trait on to a male offspring without being color-blind herself.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    [16]
  2. Cone monochromacy is the condition of having both rods and cones, but only a single kind of cone. .A cone monochromat can have good pattern vision at normal daylight levels, but will not be able to distinguish hues.^ "Individuals with deuteranopia, which is a loss of green sensitivity, have many of the same problems with hue discrimination as do protanopes, but have a fairly normal level of sensitivity across the visible spectrum.
    • My color blind kid 10 February 2010 13:37 UTC www.squidoo.com [Source type: General]

    ^ The NationMaster Encyclopedia states, "The normal human retina contains two kinds of light cells: the rod cells (active in low light) and the cone cells (active in normal daylight).
    • Designing for the Color-Blind | CreativePro.com 10 February 2010 13:36 UTC www.creativepro.com [Source type: General]

    ^ Dichromats can distinguish some colors, and are therefore less affected in their daily lives than monochromats, but they are usually aware that they have a problem with their color vision.
    • Molecular Expressions Microscopy Primer: Physics of Light and Color - Ishihara Colorblindness Test: Interactive Java Tutorial 10 February 2010 13:36 UTC micro.magnet.fsu.edu [Source type: FILTERED WITH BAYES]

    Blue cone monochromacy (X chromosome) is caused by a complete absence of L- and M-cones (red and green). .It is encoded at the same place as red-green color blindness on the X chromosome.^ My son is Red/Green color blind.
    • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

    ^ I am technically Red/Green blind.
    • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

    ^ My Dad's red/green color blind.
    • Colorblind Folks Don't Like MW2 Either - Evil Avatar 10 February 2010 13:37 UTC www.evilavatar.com [Source type: FILTERED WITH BAYES]

    Peak spectral sensitivities are in the blue region of the visible spectrum (near 440 nm). .They generally show nystagmus ("jiggling eyes"), photophobia (light sensitivity), reduced visual acuity, and myopia (nearsightedness).^ The person with nystagmus has reduced visual acuity from being unable to maintain steady fixation on objects.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ Specially treated lenses can improve vision and can also lessen discomfort by reducing the amount of light entering the eye.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ Next, let us consider the person who has normal visual acuity but cannot hold his eyes open because of his sensitivity to light.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    [17] Visual acuity usually falls to the 20/50 to 20/400 range.

Dichromacy

.Protanopes, deuteranopes, and tritanopes are dichromats; that is, they can match any color they see with some mixture of just two spectral lights (whereas normally humans are trichromats and require three lights).^ They really need to make these games so people can see brighter colors.

^ Not all cataracts require surgery, some being small enough that they do not seriously affect vision.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Myopia results when the eyeball is longer than normal or when there is some change in the eyeball which causes the light rays to be bent abnormally.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.These individuals normally know they have a color vision problem and it can affect their lives on a daily basis.^ They really need to make these games so people can see brighter colors.

^ Assuming that the blind person does not have health problems that make nursing home care necessary, elderly blind individuals should be able to learn methods to care for themselves and live in whatever type of housing situation they prefer.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Many of these babies are born mentally retarded, and they also are likely to have physical problems.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Protanopes and deuteranopes see no perceptible difference between red, orange, yellow, and green.^ For example, I probably can't see the difference between dark brown and dark green.
  • Color blindness - What things look like to color blind people. 10 February 2010 13:36 UTC digg.com [Source type: General]

^ They may not be able to tell the difference between red and green but can see blue and yellow.
  • New York Health - Color Blindness. Color blindness results from an absence or... 10 February 2010 13:36 UTC www.svcmc.org [Source type: FILTERED WITH BAYES]
  • Color Blindness - Providence Health & Services 10 February 2010 13:36 UTC www.providence.org [Source type: FILTERED WITH BAYES]
  • CIGNA - Color Blindness 10 February 2010 13:36 UTC www.cigna.com [Source type: FILTERED WITH BAYES]

^ The usual colours which they see differently are greens, yellows, oranges and reds.
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

.All these colors that seem so different to the normal viewer appear to be the same color for this two percent of the population.^ Are all of these colors really different?
  • The science and mathematics of color 10 February 2010 13:36 UTC www.inform.umd.edu [Source type: General]

^ The “normal vision” and “color deficient” images all look the same to me.

^ It means I see colors differently and that's all...
  • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

.
Test for Protanopia[Note 1]
This image contains the number 37, but someone who is protanopic may not be able to see it.
  • Protanopia (1% of males): Lacking the long-wavelength sensitive retinal cones, those with this condition are unable to distinguish between colors in the green-yellow-red section of the spectrum.^ Persons with this condition may not see well even with glasses.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ This familiar condition is predominant in males (in about 8% as opposed to around 0.5% of females) and most commonly is a sex-linked inherited characteristic transmitted through the male chromosome, although it may also result from poisoning or retinal disease.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ However, there may be someone who could offer her a ride to some of the activities in exchange for help with the gasoline purchase.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .They have a neutral point at a greenish wavelength around 492 nm – that is, they cannot discriminate light of this wavelength from white.^ And there are white people that buy into that stuff, too, because they don't want to run around feeling guilty, and they don't want to run around people thinking that they are racist.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    .For the protanope, the brightness of red, orange, and yellow is much reduced compared to normal.^ "Although deuteranopia is associated with at least a brightness response to green light (and little abnormal dimming), the names red, orange, yellow, and green seem to the deuteranope to be too many terms for colors that appear the same.
    • My color blind kid 10 February 2010 13:37 UTC www.squidoo.com [Source type: General]

    ^ His idea for the written part of the display was to write formulas in big letters, such as "Red + Yellow = Orange."
    • My color blind kid 10 February 2010 13:37 UTC www.squidoo.com [Source type: General]

    ^ Dogs do see in color, but have two-color, or dichromatic vision , that is, they cannot distinguish between red, orange, yellow or green.

    .This dimming can be so pronounced that reds may be confused with black or dark gray, and red traffic lights may appear to be extinguished.^ It may come on slowly with little pain but with blurring of vision, or it may appear suddenly, accompanied by pain and redness of the eye.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .They may learn to distinguish reds from yellows and from greens primarily on the basis of their apparent brightness or lightness, not on any perceptible hue difference.^ In the case of a yellow light, both red cones and green cones will respond.
    • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

    ^ They may not be able to tell the difference between red and green but can see blue and yellow.
    • New York Health - Color Blindness. Color blindness results from an absence or... 10 February 2010 13:36 UTC www.svcmc.org [Source type: FILTERED WITH BAYES]
    • Color Blindness - Providence Health & Services 10 February 2010 13:36 UTC www.providence.org [Source type: FILTERED WITH BAYES]
    • CIGNA - Color Blindness 10 February 2010 13:36 UTC www.cigna.com [Source type: FILTERED WITH BAYES]

    ^ After all, traffic lights are still red, green and yellow.
    • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

    .Violet, lavender, and purple are indistinguishable from various shades of blue because their reddish components are so dimmed as to be invisible.^ Since violet is close to blue and appear the same to colorblinds, reddish purple is chosen.
    • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

    ^ In a similar fashion, blues, violets, purples, and lavenders are not distinguishable to individuals with this color vision defect."  .
    • My color blind kid 10 February 2010 13:37 UTC www.squidoo.com [Source type: General]

    ^ They can see various shades of blue and can differentiate between closely related shades of grey that are not distinguishable to people.

    .E.g., pink flowers, reflecting both red light and blue light, may appear just blue to the protanope.^ There may be a case to be made that they aren't men, but they both appear to be Caucasians.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    ^ It may come on slowly with little pain but with blurring of vision, or it may appear suddenly, accompanied by pain and redness of the eye.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .Very few people have been found who have one normal eye and one protanopic eye.^ People who are achromatic are very rare.

    ^ Very few people who are colour blind are 'blind' to all colours.
    • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

    ^ At one time the U.S. Army found that colorblind persons can spot ' camouflage ' colors where those with normal color vision are fooled by them.

    .These unilateral dichromats report that with only their protanopic eye open, they see wavelengths below the neutral point as blue and those above it as yellow.^ All wavelengths below the neutral point appear blue while those at longer wavelengths appear yellow.
    • SBFAQ Part 4: Color Blindness 10 February 2010 13:36 UTC www.visualexpert.com [Source type: FILTERED WITH BAYES]

    ^ For blue-yellow defects, only a dichromatic form has been generally accepted.
    • Internetworking (2.1): Accessiblity-Designing for the Color-Challenged 10 February 2010 13:36 UTC www.internettg.org [Source type: Academic]

    ^ Protanopes and deuteranopes are red-green color blind and see only yellows and blues.
    • SBFAQ Part 4: Color Blindness 10 February 2010 13:36 UTC www.visualexpert.com [Source type: FILTERED WITH BAYES]

    This is a rare form of color blindness.
.
Test for Deuteranopia[Note 1]
This image shows a number 49, but someone who is deuteranopic may not be able to see it.
  • Deuteranopia (1% of males): Lacking the medium-wavelength cones, those affected are again unable to distinguish between colors in the green-yellow-red section of the spectrum.^ So the lack of hiring proportionate numbers would then mean that you were giving jobs to white people who didn't deserve them.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    ^ Definition of "Bigot: big⋅ot /ˈbɪgət/ Show Spelled Pronunciation [big-uht] Show IPA Use bigot in a Sentence See web results for bigot See images of bigot –noun a person who is utterly intolerant of any differing creed, belief, or opinion.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    Their neutral point is at a slightly longer wavelength, 498 nm. The deuteranope suffers the same hue discrimination problems as the protanope, but without the abnormal dimming. .Similarly, violet, lavender, purple, and blue, seem to be too many names to use logically for hues that all look alike to him.^ Since violet is close to blue and appear the same to colorblinds, reddish purple is chosen.

    ^ For example, if you use purple, brown or orange, all of which have red in them, I’ll get lost.
    • Digital Web Magazine - Color Theory for the Color-Blind 10 February 2010 13:36 UTC www.digital-web.com [Source type: General]

    ^ In a similar fashion, blues, violets, purples, and lavenders are not distinguishable to individuals with this color vision defect."  .
    • My color blind kid 10 February 2010 13:37 UTC www.squidoo.com [Source type: General]

    .This is one of the rarer forms of colorblindness making up about 1% of the male population, also known as Daltonism after John Dalton.^ Whites make up about 74% of the population of the US, so the proportion of white cabinet members in the Bush white house was slightly higher than that of the population.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    ^ And don't tell me its about the money because he makes way too much now to need the headache of an NFL team, especially one that is losing.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    ^ It's all up to us to make the most of the one life we are blessed to be given by God.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    (Dalton's diagnosis was confirmed as deuteranopia in 1995, some 150 years after his death, by DNA analysis of his preserved eyeball.) Deuteranopic unilateral dichromats report that with only their deuteranopic eye open, they see wavelengths below the neutral point as blue and those above it as yellow.
.
Test for Tritanopia[Note 1]
This image shows the number 56, but someone who is tritanopic may not be able to see it.
  • Tritanopia (less than 1% of males and females): Lacking the short-wavelength cones, those affected are unable to distinguish between the colors in the blue-yellow section of the spectrum.^ However, there may be someone who could offer her a ride to some of the activities in exchange for help with the gasoline purchase.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ A few cookbooks in recorded form also exist; these may be helpful to those who have severe circulatory problems or other special difficulties in learning Braille.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ So the lack of hiring proportionate numbers would then mean that you were giving jobs to white people who didn't deserve them.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    This form of color blindness is not sex-linked.

Anomalous trichromacy

.Those with protanomaly, deuteranomaly, or tritanomaly are trichromats, but the color matches they make differ from the normal.^ However, their matches are different from normal trichromats.
  • Internetworking (2.1): Accessiblity-Designing for the Color-Challenged 10 February 2010 13:36 UTC www.internettg.org [Source type: Academic]

^ They really need to make these games so people can see brighter colors.

^ But since this is the internet: If IW makes changes to colors on nameplates, UAVs and heartsensors, why don't they make a Milkbone controller so my DOG can play?!
  • Colorblind Folks Don't Like MW2 Either - Page 2 - Evil Avatar 10 February 2010 13:37 UTC www.evilavatar.com [Source type: FILTERED WITH BAYES]

.They are called anomalous trichromats.^ Anomalous trichromats are such a diverse group that they are difficult to characterize.
  • SBFAQ Part 4: Color Blindness 10 February 2010 13:36 UTC www.visualexpert.com [Source type: FILTERED WITH BAYES]

^ People with normal color vision are called "trichromats" because they require three primaries to match any arbitrary sample.
  • SBFAQ Part 4: Color Blindness 10 February 2010 13:36 UTC www.visualexpert.com [Source type: FILTERED WITH BAYES]

^ These "anomalous trichromats" fall into three groups, based on the primary which they overuse: .
  • SBFAQ Part 4: Color Blindness 10 February 2010 13:36 UTC www.visualexpert.com [Source type: FILTERED WITH BAYES]

.In order to match a given spectral yellow light, protanomalous observers need more red light in a red/green mixture than a normal observer, and deuteranomalous observers need more green.^ In the case of a yellow light, both red cones and green cones will respond.
  • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

^ I'd have more overlap than normal between the red and green cones, and less overlap than normal between the blue and green cones.
  • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

^ After all, traffic lights are still red, green and yellow.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

.From a practical standpoint though, many protanomalous and deuteranomalous people breeze through life with very little difficulty doing tasks that require normal color vision.^ Many people sew very little today.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Since people of color were kept out of so many endeavors every record or accomplishment should be questioned.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ Many adults with retinitis pigmentosa have a very tiny field of vision in which they see well under a good light but which is so small as to be of little use.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Some may not even be aware that their color perception is in any way different from normal.^ Seriously, context is important, but there has to be some conceivable way that context would make a difference.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ If you have a slip or undergarment that contrasts with several that are a different color or shade you may wish to mark it in the same way you would mark a t-shirt, so you don't inadvertently wear it under something light-colored or sheer.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.The only problem they have is passing a color vision test.^ I failed because I was unable to pass the color vision tests they gave me.

^ I was able to pass 100% both color vision tests the ishihara and Farnsworth.

^ A color vision problem is not always inherited.
  • CIGNA - Color Blindness 10 February 2010 13:36 UTC www.cigna.com [Source type: FILTERED WITH BAYES]

Protanomaly and deuteranomaly can be readily observed using an instrument called an anomaloscope, which mixes spectral red and green lights in variable proportions, for comparison with a fixed spectral yellow. .If this is done in front of a large audience of men, as the proportion of red is increased from a low value, first a small proportion of people will declare a match, while most of the audience sees the mixed light as greenish.^ Of course I see the red stop light.
  • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

^ In the U.S. they have designed traffic lights with this knowledge in mind because the reds have other colors mixed in and the red is always on top as another visual reminder.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ Many adults with retinitis pigmentosa have a very tiny field of vision in which they see well under a good light but which is so small as to be of little use.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

These are the deuteranomalous observers. .Next, as more red is added the majority will say that a match has been achieved.^ Instead of saying that the colorblind "intellectually" compensate for their vision, and "guess" that the object is red, I suspect it is more correct to say that the colorblind subconsciously compensate for their vision and perceive the object as red.
  • Test Blindness Color | MetaFilter 10 February 2010 13:36 UTC www.metafilter.com [Source type: General]

^ Therefore, red must be added to the spectral colour to desaturate it and make the match (figure 8) When the third primary is added to desaturate the colour mixture, negative tristimulus values result (figure 5).

.Finally, as yet more red is added, the remaining, protanomalous, observers will declare a match at a point where everyone else is seeing the mixed light as definitely reddish.^ If your cones lack one or more light sensitive chemicals you may see only two colors for example; either red and green or blue and yellow.

^ The sensitivity curve of the red cones matches the sensitivity curve of the green cones exactly; yet the brain will continue to interpret signals from each as corresponding to "red" and "green" light, respectively.
  • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

^ In the U.S. they have designed traffic lights with this knowledge in mind because the reds have other colors mixed in and the red is always on top as another visual reminder.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

.
  • Protanomaly (1% of males, 0.01% of females):[18] Having a mutated form of the long-wavelength (red) pigment, whose peak sensitivity is at a shorter wavelength than in the normal retina, protanomalous individuals are less sensitive to red light than normal.^ Next, let us consider the person who has normal visual acuity but cannot hold his eyes open because of his sensitivity to light.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ Myopia results when the eyeball is longer than normal or when there is some change in the eyeball which causes the light rays to be bent abnormally.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ But a legally blind child (one with less than ten percent of normal eyesight) cannot function efficiently using print alone.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .This means that they are less able to discriminate colors, and they do not see mixed lights as having the same colors as normal observers.^ It means I see colors differently and that's all...
    • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

    ^ But can’t see the colors doesn’t mean that they don’t need to distinguish them.
    • The Bright-F Translation System for Color Blind 10 February 2010 13:37 UTC www.medgadget.com [Source type: General]

    ^ "Individuals with deuteranopia, which is a loss of green sensitivity, have many of the same problems with hue discrimination as do protanopes, but have a fairly normal level of sensitivity across the visible spectrum.
    • My color blind kid 10 February 2010 13:37 UTC www.squidoo.com [Source type: General]

    They also suffer from a darkening of the red end of the spectrum. .This causes reds to reduce in intensity to the point where they can be mistaken for black.^ One day his little brother tricked him and told him some socks were black when they were actually red.
    • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

    ^ Some combinations that cause this include bright red on black or dark blue, yellow on blue and vice versa, green on red and vice versa, and so on.
    • Screen Space: A blog & podcast about users, texts, and technology » Blog Archive » Screen Space 6: Color Design 101 10 February 2010 13:36 UTC www.screenspace.org [Source type: General]

    .Protanomaly is a fairly rare form of color blindness, making up about 1% of the male population.^ Whites make up about 74% of the population of the US, so the proportion of white cabinet members in the Bush white house was slightly higher than that of the population.
    • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

    ^ Various forms of cataract make up one of the leading causes of blindness in this country today.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ Although the beginner may feel nervous about an electric mixer, normal safety precautions make it as safe for the blind cook as for the sighted.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .Both protanomaly and deuteranomaly are carried on the X chromosome.
  • Deuteranomaly (most common - 6% of males, 0.4% of females):[18] Having a mutated form of the medium-wavelength (green) pigment.^ Generally affecting both eyes, it most often takes the form of a loss of perception of one or two fundamental colors (red-green color blindness is the most common congenital variety), but occasionally it is complete, so that the individual literally sees only in black and white.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ This familiar condition is predominant in males (in about 8% as opposed to around 0.5% of females) and most commonly is a sex-linked inherited characteristic transmitted through the male chromosome, although it may also result from poisoning or retinal disease.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .The medium-wavelength pigment is shifted towards the red end of the spectrum resulting in a reduction in sensitivity to the green area of the spectrum.^ "Individuals with deuteranopia, which is a loss of green sensitivity, have many of the same problems with hue discrimination as do protanopes, but have a fairly normal level of sensitivity across the visible spectrum.
    • My color blind kid 10 February 2010 13:37 UTC www.squidoo.com [Source type: General]

    ^ In that sense, it is tetrachromatic because its color vision is based on four types of cones (ultraviolet, short, medium and long wavelength-sensitive).

    ^ This is false because CRT colors always have white content and because "green" cones are still slightly sensitive to relatively long wavelengths.
    • SBFAQ Part 4: Color Blindness 10 February 2010 13:36 UTC www.visualexpert.com [Source type: FILTERED WITH BAYES]

    Unlike protanomaly the intensity of colors is unchanged. .This is the most common form of color blindness, making up about 6% of the male population.^ This is the most common form of the 'handicap'.
    • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

    ^ Variations of the blue-yellow partial color blindness are the most common among males and females.
    • Screen Space: A blog & podcast about users, texts, and technology » Blog Archive » Screen Space 6: Color Design 101 10 February 2010 13:36 UTC www.screenspace.org [Source type: General]

    ^ About 7-10% of the Untied States male population is color blind and about 0.5% of the female population is color blind.
    • Screen Space: A blog & podcast about users, texts, and technology » Blog Archive » Screen Space 6: Color Design 101 10 February 2010 13:36 UTC www.screenspace.org [Source type: General]

    .The deuteranomalous person is considered "green weak". For example, in the evening, dark green cars appear to be black to Deuteranomalous people.^ People puking up their plastic cups of Coors Light on the road before it even gets dark.
    • Colorblind - The Katrina Monologues 10 February 2010 13:37 UTC www.kikomusic.com [Source type: Original source]

    ^ Even though he can see nothing at all, he is still quite properly considered to be a "sighted person."
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    Similar to the protanomates, deuteranomates are poor at discriminating small differences in hues in the red, orange, yellow, green region of the spectrum. .They make errors in the naming of hues in this region because the hues appear somewhat shifted towards red.^ That is what the red is doing here, making the berries very obvious for me in the left-hand picture but in the right-hand one, they blend in and become indistinguishable in the far branches.
    • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

    ^ For me, light green or light pink (red) appear greyish or might have a slight hue of color.
    • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

    ^ WITHIN THE FRAMEWORK THAT I ENJOY PLAYS, that's an error, because if the audience is thinking "they just cast..."
    • Wittgenstein, Shakespeare, and Cookie Monster: colorblind 10 February 2010 13:37 UTC wscmonster.blogspot.com [Source type: FILTERED WITH BAYES]

    .One very important difference between deuteranomalous individuals and protanomalous individuals is deuteranomalous individuals do not have the loss of "brightness" problem.
  • Tritanomaly (equally rare for males and females [0.01% for both]):[18] Having a mutated form of the short-wavelength (blue) pigment.^ "The only difference I ever found between the Democratic leadership and the Republican leadership is that one of them is skinning you from the ankle up and the other from the neck down."
    • Colorblind - The Katrina Monologues 10 February 2010 13:37 UTC www.kikomusic.com [Source type: Original source]

    ^ Generally affecting both eyes, it most often takes the form of a loss of perception of one or two fundamental colors (red-green color blindness is the most common congenital variety), but occasionally it is complete, so that the individual literally sees only in black and white.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    .The short-wavelength pigment is shifted towards the green area of the spectrum.^ The absorption spectra of the cones differ; one is maximally sensitive to short wavelengths, one to medium wavelengths, and the third to long wavelengths (their peak sensitivities are in the blue, yellowish-green, and yellow regions of the spectrum, respectively).
    • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]

    ^ There are three types of cone cells, each of which contains a different pigment, with each pigment being sensitive to a different range of wavelengths, corresponding to red, green, and blue.
    • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

    ^ These people can see red, green, and blue (corresponding to the peaks of the "normal" sensitivity curves), but either the red curve is shifted toward the green range of the spectrum, or the green curve is shifted toward the red.
    • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

    This is the rarest form of anomalous trichromacy color blindness. .Unlike the other anomalous trichromacy color deficiencies, the mutation for this color blindness is carried on chromosome 7.^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ Although the dog is color blind, it avoids cars as it would any other obstacle.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    ^ To put the matter simply, a female will usually not be color-blind herself unless there is an abnormal gene for color blindness on both of the X chromosomes carried by all females.
    • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

    [19] .Therefore it is equally prevalent in both male & female populations.^ About 7-10% of the Untied States male population is color blind and about 0.5% of the female population is color blind.
    • Screen Space: A blog & podcast about users, texts, and technology » Blog Archive » Screen Space 6: Color Design 101 10 February 2010 13:36 UTC www.screenspace.org [Source type: General]

    ^ This happens as male carries both XX chromosomes while female carries XY chromosomes.
    • Color Blindness - Color Blindness Test, Symtoms Of Color Blindness, Color Blindness Treatment, Color Blindness Cure, Eye Health Care 10 February 2010 13:36 UTC www.herbalcureindia.com [Source type: General]

    The OMIM gene code for this mutation is 304000 “Colorblindness, Partial Tritanomaly”.[20]

Clinical forms of color blindness

Total color blindness

.Achromatopsia is strictly defined as the inability to see color.^ However, children and adults with color vision problems can learn to compensate for their inability to see colors.
  • New York Health - Color Blindness. Color blindness results from an absence or... 10 February 2010 13:36 UTC www.svcmc.org [Source type: FILTERED WITH BAYES]
  • Color Blindness - Providence Health & Services 10 February 2010 13:36 UTC www.providence.org [Source type: FILTERED WITH BAYES]

^ In many cases, there are ways to help compensate for your inability to see or distinguish colors by the way you observe things or by watching other people's actions.
  • New York Health - Color Blindness. Color blindness results from an absence or... 10 February 2010 13:36 UTC www.svcmc.org [Source type: FILTERED WITH BAYES]
  • Color Blindness - Providence Health & Services 10 February 2010 13:36 UTC www.providence.org [Source type: FILTERED WITH BAYES]
  • CIGNA - Color Blindness 10 February 2010 13:36 UTC www.cigna.com [Source type: FILTERED WITH BAYES]

Although the term may refer to acquired disorders such as color agnosia and cerebral achromatopsia, it typically refers to congenital color vision disorders (i.e. more frequently rod monochromacy and less frequently cone monochromacy).
.In color agnosia and cerebral achromatopsia, a person cannot perceive colors even though the eyes are capable of distinguishing them.^ Blindness: Encyclopedia - Color blindness Color blindness, or color vision deficiency, in humans is the inability to perceive differences between some or all colors that other people can distinguish.

^ Dogs do see in color, but have two-color, or dichromatic vision , that is, they cannot distinguish between red, orange, yellow or green.

^ However, many such sources can still have a spectral color insofar as the eye cannot distinguish them from monochromatic sources.
  • Color encyclopedia topics | Reference.com 10 February 2010 13:36 UTC www.reference.com [Source type: FILTERED WITH BAYES]

.Some sources do not consider these to be true color blindness, because the failure is of perception, not of vision.^ Yes, I too have some color blindness.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ Color blindness is not a total loss of color vision.

^ Color blindness is also called a color vision problem.
  • CIGNA - Color Blindness 10 February 2010 13:36 UTC www.cigna.com [Source type: FILTERED WITH BAYES]

They are forms of visual agnosia.

Red-green color blindness

X-linked recessive inheritance
.Those with protanopia, deuteranopia, protanomaly, and deuteranomaly have difficulty with discriminating red and green hues.^ I'm red green deficient but I'm not sure which of those I am.
  • Color blindness - What things look like to color blind people. 10 February 2010 13:36 UTC digg.com [Source type: General]

^ Protanomaly is a mild color vision defect in which an altered spectral sensitivity of red retinal receptors (closer to green receptor response) results in poor red-green hue discrimination.
  • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]

^ The second one shows how a person with a red-green color deficit (deuteranopia) would see it and the third shows how it looks for a protanopia person, another form of red-green deficit.
  • Designrific: How I (color blind person) see the world! 10 February 2010 13:36 UTC www.designrific.com [Source type: General]

.It is sex-linked: genetic red-green color blindness affects men much more often than women, because the genes for the red and green color receptors are located on the X chromosome, of which men have only one and women have two.^ Generally affecting both eyes, it most often takes the form of a loss of perception of one or two fundamental colors (red-green color blindness is the most common congenital variety), but occasionally it is complete, so that the individual literally sees only in black and white.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Kenneth Jernigan has been a leader in the National Federation of the Blind for more than thirty-five years.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Much more efficient than FEMA Id say.
  • Colorblind - The Katrina Monologues 10 February 2010 13:37 UTC www.kikomusic.com [Source type: Original source]

.Females (46, XX) are red-green color blind only if both their X chromosomes are defective with a similar deficiency, whereas males (46, XY) are color blind if their single X chromosome is defective.^ Generally affecting both eyes, it most often takes the form of a loss of perception of one or two fundamental colors (red-green color blindness is the most common congenital variety), but occasionally it is complete, so that the individual literally sees only in black and white.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ So, too, we the blind are the only ones who can win freedom for the blind, which is both frightening and reassuring.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.The gene for red-green color blindness is transmitted from a color blind male to all his daughters who are heterozygote carriers and are usually unaffected.^ To put the matter simply, a female will usually not be color-blind herself unless there is an abnormal gene for color blindness on both of the X chromosomes carried by all females.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Moreover, the female with only one abnormal gene inherited from her father can become a "carrier" and pass the trait on to a male offspring without being color-blind herself.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ They are quite similar (or should be) for those who are totally blind or nearly so and those who are "partially sighted" and yet are blind in the terms of the usually accepted legal definition.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.In turn, a carrier woman has a fifty percent chance of passing on a mutated X chromosome region to each of her male offspring.^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ This happens as male carries both XX chromosomes while female carries XY chromosomes.
  • Color Blindness - Color Blindness Test, Symtoms Of Color Blindness, Color Blindness Treatment, Color Blindness Cure, Eye Health Care 10 February 2010 13:36 UTC www.herbalcureindia.com [Source type: General]

^ Moreover, the female with only one abnormal gene inherited from her father can become a "carrier" and pass the trait on to a male offspring without being color-blind herself.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

The sons of an affected male will not inherit the trait from him, since they receive his Y chromosome and not his (defective) X chromosome. .Should an affected male have children with a carrier or colorblind woman, their daughters may be colorblind by inheriting an affected X chromosome from each parent.^ Children especially girls should be exposed to the disease or vaccinated if possible so that they may have mild symptoms and develop resistance to German measles for the future.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ This familiar condition is predominant in males (in about 8% as opposed to around 0.5% of females) and most commonly is a sex-linked inherited characteristic transmitted through the male chromosome, although it may also result from poisoning or retinal disease.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Because one X chromosome is inactivated at random in each cell during a woman's development, it is possible for her to have four different cone types, as when a carrier of protanomaly has a child with a deuteranomalic man.^ This is because of the way the genes for the different cone cells are carried on the chromosomes.
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

^ In that sense, it is tetrachromatic because its color vision is based on four types of cones (ultraviolet, short, medium and long wavelength-sensitive).

^ The phenomenon arises when an individual receives two slightly different copies of the gene for either the medium- or long-wavelength cones, which are carried on the x-chromosome, accounting for the differences between genders.
  • Color encyclopedia topics | Reference.com 10 February 2010 13:36 UTC www.reference.com [Source type: FILTERED WITH BAYES]

.Denoting the normal vision alleles by P and D and the anomalous by p and d, the carrier is PD pD and the man is Pd.^ If a mother 'carries' the gene for red-green colour blindness (one normal and one altered gene) she will not have a colour vision problem.
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

The daughter is either PD Pd or pD Pd. Suppose she is pD Pd. Each cell in her body expresses either her mother's chromosome pD or her father's Pd. .Thus her red-green sensing will involve both the normal and the anomalous pigments for both colors.^ Color blindness - Prevalence Color blindness - Causes of color blindness Color blindness - Classification of color deficiencies Color blindness - Red-green color blindness Color blindness - Blue-yellow color blindness Color blindness - Monochromacy Color blindness - Diagnosis Color blindness - Treatment and management Color blindness - Design implications of color blindness Color blindness - Misconceptions & Compensations .

^ Protanomaly is a mild color vision defect in which an altered spectral sensitivity of red retinal receptors (closer to green receptor response) results in poor red-green hue discrimination.
  • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]

^ Bi-color and tri-color LEDs (Light Emitting Diodes): is that glowing indicator light red, yellow, or green?

.Such women are tetrachromats, since they require a mixture of four spectral lights to match an arbitrary light.^ If matches are required, the beginner may prefer large wooden ones and may need to practice lighting them; however, the experienced cook uses any available match.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

Blue-yellow color blindness

.Those with tritanopia and tritanomaly have difficulty with discriminating blue and yellow hues.^ Affected individuals lack blue and yellow sensory mechanisms while retaining those for red and green.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ The second one shows how a person with a red-green color deficit (deuteranopia) would see it and the third shows how it looks for a blue-yellow color deficit person (tritanopia).
  • Designrific: How I (color blind person) see the world! 10 February 2010 13:36 UTC www.designrific.com [Source type: General]

^ Those slightly green or blue or yellow or whatever tints don't bother me at all.
  • Anyone else color blind and loving the bright cool tint LED's? - CandlePowerForums 10 February 2010 13:37 UTC www.candlepowerforums.com [Source type: FILTERED WITH BAYES]

.Color blindness involving the inactivation of the short-wavelength sensitive cone system (whose absorption spectrum peaks in the bluish-violet) is called tritanopia or, loosely, blue-yellow color blindness.^ I, too, am a color blind female, whose grandfather was also color blind.
  • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

^ (Cones of this type are sometimes called short-wavelength cones , S cones , or, misleadingly, blue cones .
  • Color encyclopedia topics | Reference.com 10 February 2010 13:36 UTC www.reference.com [Source type: FILTERED WITH BAYES]

^ If your cones lack one or more light sensitive chemicals you may see only two colors for example; either red and green or blue and yellow.

The tritanopes neutral point occurs near a yellowish 570 nm; green is perceived at shorter wavelengths and red at longer wavelengths. .Mutation of the short-wavelength sensitive cones is called tritanomaly.^ (Cones of this type are sometimes called short-wavelength cones , S cones , or, misleadingly, blue cones .
  • Color encyclopedia topics | Reference.com 10 February 2010 13:36 UTC www.reference.com [Source type: FILTERED WITH BAYES]

^ In that sense, it is tetrachromatic because its color vision is based on four types of cones (ultraviolet, short, medium and long wavelength-sensitive).

^ The absorption spectra of the cones differ; one is maximally sensitive to short wavelengths, one to medium wavelengths, and the third to long wavelengths (their peak sensitivities are in the blue, yellowish-green, and yellow regions of the spectrum, respectively).
  • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]

.Tritanopia is equally distributed among males and females.^ Only 5% of people who are colour-blind have blue colour blindness, and this is equal in males and females, because the genes for it are on a different chromosome (chromosome 7).
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

.Jeremy H. Nathans (with the Howard Hughes Medical Institute) proved that the gene coding for the blue receptor lies on chromosome 7, which is shared equally by men and women.^ Hogness D.S. (1986) Localisation of the human blue cone pigment gene to chromosome band 7q31.3-32.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

^ Men are more apt to be color blind than women, and red/green receptors (cones) are more apt to be defective than the blue/yellow.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ (PubMed id 1531728) 3, 4, 6 Weitz C.J....Nathans J. (1992) Molecular genetics of human color vision: the genes encoding blue, green, and red pigments.
  • OPN1SW Gene - GeneCards | OPSB Protein | OPSB Antibody 10 February 2010 13:36 UTC www.genecards.org [Source type: Academic]

Therefore it is not sex-linked. This gene does not have any neighbor whose DNA sequence is similar. .Blue color blindness is caused by a simple mutation in this gene.^ To put the matter simply, a female will usually not be color-blind herself unless there is an abnormal gene for color blindness on both of the X chromosomes carried by all females.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Some blind people prefer to wear primarily one color of socks, all black, all white, all blue.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

)[21]

Prevalence

.Color blindness affects a significant number of people, although exact proportions vary among groups.^ The level of color blindness will be different in different people.
  • Color Blindness - Color Blindness Test, Symtoms Of Color Blindness, Color Blindness Treatment, Color Blindness Cure, Eye Health Care 10 February 2010 13:36 UTC www.herbalcureindia.com [Source type: General]

^ The symptoms of color blindness are different in different people.
  • Color Blindness - Color Blindness Test, Symtoms Of Color Blindness, Color Blindness Treatment, Color Blindness Cure, Eye Health Care 10 February 2010 13:36 UTC www.herbalcureindia.com [Source type: General]

^ To understand how color blindness affects individuals there are a few tests you can perform using the first set of links above.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

.In Australia, for example, it occurs in about 8 percent of males and only about 0.4 percent of females.^ Color vision deficiency seems to occur in about 8% - 12% of males of European origin and about one-half of 1% of females.

^ Only 5% of people who are colour-blind have blue colour blindness, and this is equal in males and females, because the genes for it are on a different chromosome (chromosome 7).
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

^ The genes that lead to red-green colour blindness are on the X chromosome [males have only one of these and females have two].
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

[22] .Isolated communities with a restricted gene pool sometimes produce high proportions of color blindness, including the less usual types.^ The problem is that there are so many differnt types of color blindness that it would be impossible to get a representative of all of them in beta.
  • Beta: Color-Blindness - Page 2 - Stargate Worlds Game Forums 10 February 2010 13:36 UTC forums.stargateworlds.com [Source type: General]

^ An article at about.com on Designing for the Color Blind There's more, including a really good simulation at Lawrence Livermore, but I can't find that one anymore.

^ Being color blind and playing games can be extremely frustrating sometimes.
  • Colorblind gaming or: Table Tennis is impossibly hard! 10 February 2010 13:37 UTC www.joystiq.com [Source type: FILTERED WITH BAYES]

Examples include rural Finland, Hungary, and some of the Scottish islands. .In the United States, about 7 percent of the male population – or about 10.5 million men – and 0.4 percent of the female population either cannot distinguish red from green, or see red and green differently (Howard Hughes Medical Institute, 2006)[23].^ I see him as president of the United States, and I'm more concerned about his policies.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ In July of 1990 Jernigan received an award for distinguished service from the President of the United States.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ These members of the Board of Directors represent a wide cross section of the blind population of the United States.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.It has been found that more than 95 percent of all variations in human color vision involve the red and green receptors in male eyes.^ Species that have color receptors different from humans, e.g.
  • Color encyclopedia topics | Reference.com 10 February 2010 13:36 UTC www.reference.com [Source type: FILTERED WITH BAYES]

^ There is much more variation in color vision in humans than in old world monkeys (8-11% in caucasian males).
  • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

^ Red letters (normal color vision)   .
  • Firelily Designs - Color Vision, Color Deficiency 10 February 2010 13:36 UTC www.firelily.com [Source type: FILTERED WITH BAYES]

.It is very rare for males or females to be "blind" to the blue end of the spectrum.^ I’m color blind, which for a girl is very rare.
  • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

^ The genes that lead to red-green colour blindness are on the X chromosome [males have only one of these and females have two].
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

^ Red-green colour blindness is usually inherited, and occurs in about 8% of males and only about 0.4% of females.
  • Parenting and Child Health - Health Topics - Colour blindness 10 February 2010 13:36 UTC www.cyh.com [Source type: FILTERED WITH BAYES]

Prevalence of color blindness
Men Women Total References
Overall
Overall (United States)
Red-green (Overall) 7 to 10% [24][25]
Red-green (Caucasians) 8% [26]
Red-green (Asians) 5% [26]
Red-green (Africans) 4% [26]
Monochromacy
Rod monochromacy (dysfunctional, abnormally shaped or no cones) 0.00001% 0.00001% [27]
Dichromacy 2.4% 0.03% 1.30% [24][27]
Protanopia (red deficient: L-cone absent) 1% to 1.3% 0.02% [24][27]
Deuteranopia (green deficient: M-cone absent) 1% to 1.2% 0.01% [24][27]
Tritanopia (blue deficient: S-cone absent) 0.001% 0.03% [27]
Anomalous Trichromacy 6.3% 0.37% [27]
Protanomaly (red deficient: L-cone defect) 1.3% 0.02% [27]
Deuteranomaly (green deficient: M-cone defect) 5.0% 0.35% [27]
Tritanomaly (blue deficient: S-cone defect) 0.01% 0.01% [27]

Diagnosis

.
Example of an Ishihara color test plate.[Note 1] The numeral "74" should be clearly visible to viewers with normal color vision.
^ One of the most familiar tests consists of a circle containing dots of different colors, in which the subject with normal color vision is supposed to discern one number, while a person with defective color vision is likely to see another.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

Viewers with dichromacy or anomalous trichromacy may read it as "21", and viewers with achromatopsia may not see numbers.
An Ishihara test image as seen by able-bodied and by persons with a variety of Daltonism forms
.The Ishihara color test, which consists of a series of pictures of colored spots, is the test most often used to diagnose red-green color deficiencies.^ Generally affecting both eyes, it most often takes the form of a loss of perception of one or two fundamental colors (red-green color blindness is the most common congenital variety), but occasionally it is complete, so that the individual literally sees only in black and white.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The most common is melanoma, a malignant spot of color.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The long white cane or the guide dog are the tools most often used for independent travel.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.A figure (usually one or more Arabic digits) is embedded in the picture as a number of spots in a slightly different color, and can be seen with normal color vision, but not with a particular color defect.^ One of the most familiar tests consists of a circle containing dots of different colors, in which the subject with normal color vision is supposed to discern one number, while a person with defective color vision is likely to see another.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The visual loss is progressive, so that the individual usually becomes legally blind by young adulthood and slowly loses more and more vision thereafter.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ This is likely to happen if the two eyes focus differently because of strabismus (see below) or because one eye is much more nearsighted than the other.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.The full set of tests has a variety of figure/background color combinations, and enable diagnosis of which particular visual defect is present.^ This workbook is a practical, visual guide that takes the guesswork out of choosing and using color combinations.
  • Color Tutorials Articles: Colors for Web Sites, Color Management, Web Design Colors Schemes, Browser Safe aka Websafe Colors, Color Blindness & Deficiencies, Color Meanings & Psychology - Color Resources, WebsiteTips.com 10 February 2010 13:36 UTC websitetips.com [Source type: General]

^ To understand how color blindness affects individuals there are a few tests you can perform using the first set of links above.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ Setting the table usually presents no particular problem.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.The anomaloscope, described above, is also used in diagnosing anomalous trichromacy.^ The very mild anomalous trichromats who may or may not fail pseudoisochromatic plates can be diagnosed with the Nagel anomaloscope.

.However, the Ishihara color test is criticized for containing only numerals and thus not being useful for young children, who have not yet learned to use numerals.^ Being friendly to colorblind people does not necessarily mean that one should not use colors.
  • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

^ Just a question...is anyone in the beta being asked to test for...color-blindness issues?
  • Beta: Color-Blindness - Stargate Worlds Game Forums 10 February 2010 13:36 UTC forums.stargateworlds.com [Source type: FILTERED WITH BAYES]

^ Even while the skills of reading and writing Braille are being learned, she can make use of Braille in labeling canned goods and medicines.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.It is often stated that it is important to identify these problems as soon as possible and explain them to the children to prevent possible problems and psychological traumas.^ Announcements often contain important information and you should read them as soon as possible.

^ As with other eye conditions, early detection and treatment of these problems can help prevent blindness.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ They are often quite important so you should read them where possible.

.For this reason, alternative color vision tests were developed using only symbols (square, circle, car).^ One of the most familiar tests consists of a circle containing dots of different colors, in which the subject with normal color vision is supposed to discern one number, while a person with defective color vision is likely to see another.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Most clinical tests are designed to be fast, simple, and effective at identifying broad categories of color blindness.^ Site design and Color Blindness .
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ I'm a designer with super color-blind powers!
  • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

^ This is the most common type of color blindness.
  • Color blindness 10 February 2010 13:36 UTC www.drexelmed.edu [Source type: Academic]

.In academic studies of color blindness, on the other hand, there is more interest in developing flexible tests to collect thorough datasets, identify copunctal points, and measure just noticeable differences.^ They should do so, so that others can then point out just how MMFA got things wrong.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ On the other hand, some people have severe diabetes for many years and never develop eye problems.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ In most cases, however, you can use whatever you have on hand just as well as something that has been adapted for use by the blind.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

[28]

Treatment and management

.There is generally no treatment to cure color deficiencies.^ There is no known treatment.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ There is no cure for albinism.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ There is no treatment for color blindness, and it cannot be overcome through any type of eye exercises.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.However, certain types of tinted filters and contact lenses may help an individual to better distinguish different colors.^ However, there may be someone who could offer her a ride to some of the activities in exchange for help with the gasoline purchase.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Raised markings can be put on dials in a variety of ways and may be helpful to a blind individual.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The individual may find he or she is more comfortable and sees better if the head is tilted or moved slightly to compensate for the involuntary movements, and often this will be done unconsciously.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

Optometrists can supply a singular red-tint contact lens to wear on the non-dominant eye.[29] This may enable the wearer to pass some color blindness tests, but they have little practical use. .The effect of wearing such a device is akin to wearing red/blue 3D glasses and can take some time getting used to as certain wavelengths can "jump" out and be overly represented[citation needed].^ They're also taking some of the quotes above out of context, in that they aren't mentioning that some were part of a satire.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ Some blind people prefer to wear primarily one color of socks, all black, all white, all blue.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ He or she is able to avoid directly touching any of the food with the fingers, by such means as wearing thin plastic gloves or using a utensil or appliance.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Additionally, computer software and cybernetic devices have been developed to assist those with visual color difficulties such as an eyeborg, a "cybernetic eye" that allows individuals with color blindness to hear sounds representing colors.^ Other examples similar to this could be given, but the kitchen timer shows why you may not need a special device for the blind, even if you hear it advertised.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Without such software a computer would be impossible to use.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Techniques and instruments have been developed that make it possible for blind individuals to do most activities for which sight is ordinarily considered necessary.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

[30]
The GNOME desktop environment provides colorblind accessibility using the gnome-mag and the libcolorblind software. Using a gnome applet, the user may switch a color filter on and off choosing from a set of possible color transformations that will displace the colors in order to disambiguate them. .The software enables, for instance, a color blind person to see the numbers in the ishihara test.^ None of these methods will always be satisfactory, but a combination of them will enable a blind person to get the things he or she needs and wants: .
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The older blind person may want to learn enough Braille to put labels on things or to write down telephone numbers.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ One of the most familiar tests consists of a circle containing dots of different colors, in which the subject with normal color vision is supposed to discern one number, while a person with defective color vision is likely to see another.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.In September 2009, the journal Nature reported that researchers at the University of Washington and University of Florida were able to give trichromatic vision to squirrel monkeys, which normally have only dichromatic vision, using gene therapy.^ Reply Report Abuse by bintx ( October 14, 2009 10:42 am ET ) 5 3 Only one quote in Burwell's article has been found to be suspect and it is still being researched.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

[31]

Design implications of color blindness

.Color codes present particular problems for those with color deficiences as they are often difficult or impossible for them to perceive.^ Setting the table usually presents no particular problem.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Stirring by hand usually presents no particular problem.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ In fact, they are often harmful since they place the wrong emphasis on blindness and its problems.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Good graphic design avoids using color coding, or color contrasts alone, to express information as this not only helps color blind people, but also aids understanding by normally sighted people.^ This gives blind people access to the same information sighted people get from computers.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ What measuring devices do blind people use?
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Can blind people use computers?
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

The use of Cascading Style Sheets on the world wide web allows pages to be given an alternative color scheme for color-blind readers. .This color scheme generator helps a graphic designer see color schemes as seen by eight types of color blindness.^ In 1914 he decided to return to the California School for the Blind as a teacher so that he might help the next generation of the blind have the opportunities that he had missed.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ We can help you with problems you have because you cannot see well, and we can provide general information about eye diseases and causes of blindness.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ There is no treatment for color blindness, and it cannot be overcome through any type of eye exercises.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.For an example of a map that could present a significant problem to a color blind reader, see this graphic from a New York Times article.^ The New York Times publishes a large print weekly summary of its columns and features.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ We can help you with problems you have because you cannot see well, and we can provide general information about eye diseases and causes of blindness.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The Braille Monitor keeps blind and interested sighted readers informed about issues, news, and events which have special significance to the blind and those who are losing sight.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.The typical red-green color blind reader will find the green sections of the map nearly indistinguishable from the orange, rendering the graphic unreadable.^ My son is Red/Green color blind.
  • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

^ I have red/green color blindness (the most common).
  • Colorblind gaming or: Table Tennis is impossibly hard! 10 February 2010 13:37 UTC www.joystiq.com [Source type: FILTERED WITH BAYES]

^ I am technically Red/Green blind.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

Designers need to take into account that color-blindness is highly sensitive to differences in material. .For example, a red-green colorblind person who is incapable of distinguishing colors on a map printed on paper may have no such difficulty when viewing the map on a computer screen or television.^ If you are a beginner who has had little or no experience in using a knife, you may find it easier and safer at first to cut downward toward a cutting board.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Braille can be fun and useful to the older person who is losing sight, but it should not be viewed as an obligation.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Any person who is unable to read standard print is eligible to borrow these materials.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.In addition, some color blind people find it easier to distinguish problem colors on artificial materials, such as plastic or in acrylic paints, than on natural materials, such as paper or wood.^ Yes, I too have some color blindness.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ But it is more difficult than people realize to be color-blind.
  • Color + Design Blog / As Seen By The Color Blind by COLOURlovers 10 February 2010 13:37 UTC www.colourlovers.com [Source type: General]

^ RE: The problem with color blindness .
  • Okayplayer.com Boards - Viewing topic #103575 - The problem with color blindness 10 February 2010 13:36 UTC board.okayplayer.com [Source type: FILTERED WITH BAYES]

.Third, for some color blind people, color can only be distinguished if there is a sufficient "mass" of color: thin lines might appear black while a thicker line of the same color can be perceived as having color.^ However, there are also scholarships which are only available to blind students.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Are there special nursing or retirement homes for elderly blind people?
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The employment situation for blind people will only improve to the extent that good training is received and beliefs and attitudes are changed.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.When the need to process visual information as rapidly as possible arises, for example in an emergency situation, the visual system may operate only in shades of gray, with the extra information load in adding color being dropped.^ If the dial is particularly hard to mark, for example, it may be possible to do most of the marking on the background instead of on the dial.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Although the beginner may feel hesitant about lighting a gas stove or oven, the blind cook need only follow normal safety precautions and observe the operation of the stove by means other than sight.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.October 2009" style="white-space:nowrap;">[citation needed] This is an important possibility to consider when designing, for example, emergency brake handles or emergency phones.^ Reply Report Abuse by OhMy ( October 14, 2009 5:32 pm ET ) 2 This is a great example of how facts don't matter to most people.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ Reply Report Abuse by Brabantio ( October 14, 2009 4:14 pm ET ) 6 1 Is it possible that the vast majority of inflammatory or false comments happen to come from white people?
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ Reply Report Abuse by edrossinoelwein9669 ( October 15, 2009 4:25 pm ET ) 1 I guess Bill Clinton and Al Gore aren't white men.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

Color blindness and occupations

.Color blindness may make it difficult or impossible for a person to engage in certain occupations.^ Practice will make these techniques simple and commonplace, although they may seem difficult or frustrating at first.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Never feed the dog since feeding it may make control of the dog difficult in a restaurant.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ A few relatively simple techniques will make it possible for a blind person to do any kind of sewing he or she wishes to do.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Persons with color blindness may be legally or practically barred from occupations in which color perception is an essential part of the job (e.g., mixing paint colors), or in which color perception is important for safety (e.g., operating vehicles in response to color-coded signals).^ Some of these things may seem unlikely for a blind person, but they aren't.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ With a little practice you will be able to find your way by yourself, and it will help you gain confidence in yourself as a blind person.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The experience of blind persons is that, with proper training and opportunity, the average blind person can do the average job in the average place of business and do it as well as his or her sighted colleagues.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

This occupational safety principle originates from the Lagerlunda train crash of 1875 in Sweden. .Following the crash, Professor Alarik Frithiof Holmgren, a physiologist, investigated and concluded that the color blindness of the engineer (who had died) had caused the crash.^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Professor Holmgren then created the first test using different-colored skeins to exclude people from jobs in the transportation industry on the basis of color blindness.^ What jobs can blind people do?
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ They are readable and interesting, giving the general public an opportunity to know what blindness is really like and how the people who live it on a daily basis feel.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Blind people use as many different techniques for shopping as sighted people do, and everyone will use a variety of different techniques for different occasions.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

[32]

Driving motor vehicles

Some countries (e.g. Romania and Turkey[33]) have refused to grant individuals with color blindness driving licenses. In Romania, there is an ongoing campaign to remove the legal restrictions that prohibit colorblind citizens from getting drivers' licenses.[34]
The usual justification for such restrictions is that drivers of motor vehicles must be able to recognize color-coded signals, such as traffic lights or warning lights.

Piloting aircraft

.While many aspects of aviation depend on color coding, only a few of them are critical enough to be interfered with by some milder types of color blindness.^ Some blind people prefer to wear primarily one color of socks, all black, all white, all blue.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ There is no treatment for color blindness, and it cannot be overcome through any type of eye exercises.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ On the other hand a male, who carries only one X chromosome, will be color-blind if it contains an abnormal gene.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

Some examples include color-gun signaling of aircraft that have lost radio communication, color-coded glide-path indications on runways, and the like. .Some jurisdictions restrict the issuance of pilot credentials to persons who suffer from color blindness for this reason.^ For all these reasons, the blind person needs to learn all the common means of cooking and baking.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ A blind person who receives Supplemental Security Income payments is eligible for state administered Medicaid assistance without any waiting period.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ There is no reason for a blind person to be frightened of hot stoves, electric mixers, sharp knives, or anything else in the kitchen.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.Restrictions may be partial, allowing color-blind persons to obtain certification but with restrictions, or total, in which case color-blind persons are not permitted to obtain piloting credentials at all.^ Total blindness may result.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ For all these reasons, the blind person needs to learn all the common means of cooking and baking.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Some of these things may seem unlikely for a blind person, but they aren't.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.In the United States, the Federal Aviation Administration requires that pilots be tested for normal color vision as part of the medical certification that is prerequisite to obtaining a pilot's license.^ Limbaugh has also advanced the theory that Obama was not born in the United States, saying that "God does not have a birth certificate.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ Although there are in the United States at the present time many organizations and agencies for the blind, there is only one National Federation of the blind.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ The National Federation of the Blind is asking state licensing officials to require teachers of the blind and visually handicapped to be competent in reading and writing Braille and to require that instruction in Braille be available to every visually handicapped child if parents want it.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.If testing reveals color blindness, the applicant may be issued a license with restrictions, such as no night flying and no flying by color signals—such a restriction effectively prevents a pilot from working for an airline.^ In any event, use of various charts to test for color blindness is commonly included as part of an eye examination, especially for drivers and workers in industry and transportation, where the ability to distinguish colored signals is important.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Developments such as optic disk topography mapping, the laser scanning ophthalmoscope, and color perimetry may assist in early detection and treatment of this disorder.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ There is no treatment for color blindness, and it cannot be overcome through any type of eye exercises.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.The government allows several types of tests, including medical standard tests (e.g., the Ishihara, Dvorine, and others) and specialized tests oriented specifically to the needs of aviation.^ A few cookbooks in recorded form also exist; these may be helpful to those who have severe circulatory problems or other special difficulties in learning Braille.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Braille watches, white canes, and other special appliances for the blind are included in this privilege.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Other examples similar to this could be given, but the kitchen timer shows why you may not need a special device for the blind, even if you hear it advertised.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

If an applicant fails the standard tests, he or she will receive a restriction on their medical certificate that states- "Not valid for night flying or by color signal control." .He/she may apply to the FAA to take a specialized test, administered by the FAA. Typically, this test is the "color vision light gun test."^ Specially treated lenses can improve vision and can also lessen discomfort by reducing the amount of light entering the eye.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Symptoms may include intermittent blurred vision, nausea, inability to adjust eyes to darkened rooms, seeing colored halos around lights, and reduced side vision.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

For this test an FAA inspector will meet the pilot at an airport with an operating control tower, and the color signal light gun will be shone at the pilot from the tower, and he or she must identify the color. .If he passes, he may be issued a waiver, which states that the color vision test is no longer required during medical examinations.^ Depending on your financial circumstances, it may be possible to qualify for medical assistance through your State Department of Social Services.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Just because a person loses vision doesn't mean that she can no longer do the things that have interested her.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

He will then receive a new medical certificate with the restriction removed. This was once a Statement of Demonstrated Ability (SODA), but the SODA was dropped, and converted to a simple waiver (letter) early in the 2000s.[35]
.Research published in 2009 carried out by the City University of London's Applied Vision Research Centre, sponsored by the UK's Civil Aviation Authority and the US Federal Aviation Administration, has established a more accurate assessment of colour deficiencies in pilot applicants' red-green and yellow-blue colour range which could lead to a 35% reduction in the number of prospective pilots who fail to meet the minimum medical threshold.^ His most brilliant student was Jacobus tenBroek, who established the National Federation of the Blind in 1940.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

[36]

Art

Inability to distinguish color does not necessarily preclude the ability to become a celebrated artist. The expressionist painter Clifton Pugh, three-time winner of Australia's Archibald Prize, on biographical, gene inheritance and other grounds has been identified as a protanope.[37] Nineteenth century French artist Charles Méryon became successful by concentrating on etching rather than painting after he was diagnosed as having a red-green deficiency.[38]

Misconceptions and compensations

Simulation of the normal (above) and dichromatic (below) perception of red and green apples.
Color blindness is not the swapping of colors by the observer — grass is never red, and stop signs are never green. .The color impaired do not learn to call red "green" and vice versa.^ My son is Red/Green color blind.
  • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

^ When I learned that color blindness often results in the inability to distinguish between red and green, I thought that would make driving difficult, but figured you could probably get used to stopping for the light on top and going for the light on bottom.
  • mental_floss Blog » The Quick 10: 10 Famous Color Blind People 10 February 2010 13:37 UTC www.mentalfloss.com [Source type: General]

^ According to Wikipedia there are an estimated 10.5 million American men who are red green color blind.
  • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]
  • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

.However, dichromats often confuse red and green items.^ Spectral sensitivity measurements (Wald-Marre spectral sensitivity functions and Stiles' p -mechanisms) However, the trichomatic theory fails to account for the four unique colours: red, green, yellow and blue, and also fails to explain why dichromats can perceive white and yellow.

^ Fig 4 Combination of colors that are confusing for red-green colorblinds Difficult to distinguish certain colors which differ only in their red or green component.
  • Color Universal Design (CUD) / Colorblind Barrier Free 10 February 2010 13:36 UTC jfly.iam.u-tokyo.ac.jp [Source type: FILTERED WITH BAYES]

^ It's not enough to have a Green Arrow and a Red Arrow, because those can be confusing.
  • Beta: Color-Blindness - Stargate Worlds Game Forums 10 February 2010 13:36 UTC forums.stargateworlds.com [Source type: FILTERED WITH BAYES]

.For example, they may find it difficult to distinguish a Braeburn apple from a Granny Smith and in some cases, the red and green of a traffic light without other clues (e.g., shape or location).^ There may be a case to be made that they aren't men, but they both appear to be Caucasians.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ This condition can affect other parts of the eyecornea, retina, sclera, for example and may be serious enough to lead to loss of vision.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Some of these things may seem unlikely for a blind person, but they aren't.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

Anomalous Trichromats tend to learn to use texture and shape clues and so are often able to spot camouflage clothing, netting, and paint that has been designed to deceive individuals with color-normal vision.[1]
.Traffic light colors are confusing to some dichromats as there is insufficient apparent difference between the red/amber traffic lights, and that of sodium street lamps; also the green can be confused with a grubby white lamp.^ Some blind people prefer to wear primarily one color of socks, all black, all white, all blue.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ Seriously, context is important, but there has to be some conceivable way that context would make a difference.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

^ Myopia results when the eyeball is longer than normal or when there is some change in the eyeball which causes the light rays to be bent abnormally.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.This is a risk factor on high-speed undulating roads where angular cues can't be used.^ (Glass may be etched by using a portable high-speed grinder with a V-shaped silicon carbide stone, or a vibrating engraving tool with a silicon carbide or diamond point.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

British Rail color lamp signals use more easily identifiable colors: the red is really blood red, the amber is quite yellow and the green is a bluish color. .Most British road traffic lights are mounted vertically on a black rectangle with a white border (forming a "sighting board") and so dichromats simply look for the position of the light within the rectangle — top, middle or bottom.^ He came to the conclusion that most of black society does not readily accept offspring of such relationships, and neither does white society, he said.
  • Limbaugh's "colorblind" history of racially charged comments | Media Matters for America 10 February 2010 13:37 UTC mediamatters.org [Source type: FILTERED WITH BAYES]

.Color blindness very rarely means complete monochromatism.^ Once a dreaded and very common cause of blindness, it is now preventable by means of modern hygiene and medical care.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

.In almost all cases, color blind people retain blue-yellow discrimination, and most color blind individuals are anomalous trichromats rather than complete dichromats.^ Yellow colour blindness affect less than 1% of individuals.
  • Site design and Color Blindness - WebProWorld 10 February 2010 13:36 UTC www.webproworld.com [Source type: General]

^ Q:I'm unwilling to treat people as groups rather than as individuals.
  • http://www.mdcbowen.org/p2/rm/blind.html 10 February 2010 13:36 UTC www.mdcbowen.org [Source type: Original source]

^ I'm a color blind too like all of you.
  • Blindness | Critique Wall.com 10 February 2010 13:36 UTC critiquewall.com [Source type: Original source]

.In practice this means that they often retain a limited discrimination along the red-green axis of color space, although their ability to separate colors in this dimension is severely reduced.^ Practice will make these techniques simple and commonplace, although they may seem difficult or frustrating at first.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ They are often able to provide medical services at a reduced rate.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

^ This makes sorting several colors of socks simple, since they should not get mixed together.
  • If Blindness Comes: Complete Issue 10 February 2010 13:36 UTC www.nfb.org [Source type: Original source]

See also

Notes

  1. ^ a b c d Note: Because of variations in computer displays, these illustrations must not be used for diagnosis of color-blindness. An inability to see the numbers on a computer display is not necessarily indicative of color blindness. Only official tests administered in person are reliable for diagnosis.

References

  1. ^ a b Dalton J, 1798 "Extraordinary facts relating to the vision of colours: with observations" Memoirs of the Literary and Philosophical Society of Manchester 5 28-45
  2. ^ Morgan MJ, Adam A, Mollon JD. "Dichromats detect colour-camouflaged objects that are not detected by trichromats." Proc Biol Sci. 1992 Jun 22;248 (1323):291-5. PMID 1354367.
  3. ^ Waggoner, Terrace L.. "About Color Blindness (Color Vision Deficiency) :Clinical information about color blindness". Colors for the Color Blind. http://www.toledo-bend.com/colorblind/aboutcb.asp. Retrieved 2009-10-29. 
  4. ^ Onishi, A., Koike, S., Ida, M., Imai, H., Shichida, Y., Takenaka, O., et al. (1999). Dichromatism in macaque monkeys. Nature, 402,139-140.
  5. ^ Jordan G, Mollon JD.,A study of women heterozygous for colour deficiencies. Vision Res. 1993 Jul;33(11):1495-508. Jameson K.A., Richer color experience in observer with multiple photopigment opsin genes, Psychomomic Bulletin & Review, 2001, 8(2),244-261
  6. ^ Sharpe, LT; Stockman A, Jägle H, Nathans J (1999). "Opsin genes, cone photopigments, color vision and color blindness". in Gegenfurtner KR, Sharpe LT. Color Vision: From Genes to Perception. Cambridge University Press. ISBN 9780521004398. http://books.google.com/books?id=4zQMQLLVkFYC. 
  7. ^ http://www.colblindor.com/2006/04/28/colorblind-population/
  8. ^ a b "Color Blindness." University of Illinois Eye Center, Department of Ophthalmology and Visual Sciences. Retrieved September 29, 2006.
  9. ^ Kokotailo R, Kline D. "Congenital Colour Vision Deficiencies." University of Calgary, Department of Psychology, Vision & Aging Lab. Retrieved September 29, 2006.
  10. ^ a b c d "Guidelines: Color Blindness." Tiresias.org. Retrieved September 29, 2006.
  11. ^ a b c d e f g h i Cassin, B. and Solomon, S. Dictionary of Eye Terminology. Gainsville, Florida: Triad Publishing Company, 1990.
  12. ^ Spring, Kenneth R.; Matthew J. Parry-Hill; Thomas J. Fellers; Michael W. Davidson. "Human Vision and Color Perception". Florida State University. http://micro.magnet.fsu.edu/primer/lightandcolor/humanvisionhome.html. Retrieved 2007-04-05. 
  13. ^ Paul S. Hoffman. "Accommodating Color Blindness" (PDF). http://www.digitalspaceart.com/articles/ColorBlindness.pdf. Retrieved 2009-07-01. 
  14. ^ Neitz, Maureen E., PhD. "Severity of Colorblindness Varies". Medical College of Wisconsin. http://healthlink.mcw.edu/article/999211295.html. Retrieved 2007-04-05. 
  15. ^ a b Byrne A, Hilbert D. "A Glossary of Color Science." Originally published in Readings on Color, Volume 2: The Science of Color. (MIT Press, 1997). Retrieved November 7, 2006.
  16. ^ http://www.eye-disease.info/achromatopsia.php
  17. ^ *Weiss AH, et al. 1989. "Blue cone monochromatism" J Pediatr Ophthalmol Strabismus. 1989; 11: 315-7
  18. ^ a b c Kalloniatis, Michael and Luu, Charles. "Psychophysics of Vision: The Perception of Color". http://webvision.med.utah.edu/KallColor.html#deficiencies. Retrieved 2007-04-02. 
  19. ^ Montgomery, Ted M., O.D.. "The Macula". http://www.tedmontgomery.com/the_eye/macula.html#X-chrome. Retrieved 2007-04-02. 
  20. ^ "Disease-causing Mutations and protein structure". UCL Biochemistry BSM Group. http://www.biochem.ucl.ac.uk/bsm/humgen/chr__034.html#304000. Retrieved 2007-04-02. 
  21. ^ "Seeing, Hearing and Smelling the World, a Report for the Howard Hughes Medical Institute". Howard Hughes Medical Institute. http://www.hhmi.org/senses/b130.html. Retrieved 2010-02-18. 
  22. ^ "Colour blindness". Better Health Channel. http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Colour_blindness. Retrieved 2007-04-02. 
  23. ^ "Seeing, Hearing and Smelling the World, a Report for the Howard Hughes Medical Institute". Howard Hughes Medical Institute. http://www.hhmi.org/senses/b130.html. Retrieved 2010-02-18. 
  24. ^ a b c d "Prevalence and Incidence of Color blindness". WrongDiagnosis.com. 2008-06-22. http://www.wrongdiagnosis.com/c/color_blindness/prevalence.htm. Retrieved 2008-07-10. 
  25. ^ "Color Blindness: More Prevalent Among Males". Hhmi.org. http://www.hhmi.org/senses/b130.html. Retrieved 2009-04-16. 
  26. ^ a b c Masataka Okabe, Kei Ito (2008-02-15). "Colorblind Barrier Free". J*Fly. http://jfly.iam.u-tokyo.ac.jp/color/. Retrieved 2008-07-10. 
  27. ^ a b c d e f g h i Archive.org
  28. ^ Toufeeq. "HubMed Abstracts". Hubmed.org. http://www.hubmed.org/display.cgi?uids=15192692. Retrieved 2009-04-16. 
  29. ^ Zeltzer,, Harry I. (March 1991). "Patent application for contact lens for correction of color blindness". freepatentsonline.com. FreePatentsOnline.com. http://www.freepatentsonline.com/4998817.html. Retrieved 2009-10-28. 
  30. ^ Anon (19 January 2005). "Seeing things in a different light". BBC Devon features. BBC. http://www.bbc.co.uk/devon/news_features/2005/eyeborg.shtml. Retrieved 2009-10-30. 
  31. ^ Colour blindness corrected by gene therapy : Nature News
  32. ^ Vingrys, A.J., Cole, B.L., Origins of Colour Vision Standards within the Transportation Industry, Ophthmalic and Physiological Optics, 1986:6(4)369-75
  33. ^ "Colour blindness treatment". World Eye Centers Istanbul. http://www.worldeyelasik.com/other-treatments/color-blindness-treatment.html. Retrieved 2009-07-05. 
  34. ^ "Petition to European Union on Colorblind’s condition in Romania". http://discromat.wordpress.com/2007/08/15/time-out/. Retrieved 2007-08-21. 
  35. ^ "Aerospace Medical Dispositions - Color vision". http://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/ame/guide/app_process/exam_tech/item52/amd/. Retrieved 2009-04-11. 
  36. ^ Warburton, Simon (29 May 2009). "Colour-blindness research could clear more pilots to fly: UK CAA". Air transport. Reed Business Information. http://www.flightglobal.com/articles/2009/05/29/327137/colour-blindness-research-could-clear-more-pilots-to-fly-uk.html. Retrieved 29 October 2009. 
  37. ^ Cole BL, Harris RW (September 2009). "Colour blindness does not preclude fame as an artist: celebrated Australian artist Clifton Pugh was a protanope". Clin Exp Optom 92 (5): 421–8. doi:10.1111/j.1444-0938.2009.00384.x. PMID 19515095. 
  38. ^ Anon. "Charles Meryon". Art Encyclopedia. The Concise Grove Dictionary of Art.. Oxford University Press. http://www.answers.com/topic/charles-m-ryon. Retrieved 7 January 2010. 

Bibliography

  • Kaiser, Peter K.; Boynton, R.M. (1996). Human Color Vision (2nd ed.). Washington, DC: Optical Society of America. ISBN 1-55752-461-0. 
  • McIntyre, Donald (2002). Colour Blindness: Causes and Effects. UK: Dalton Publishing. ISBN 0-9541886-0-8. 
  • Shevell, Steven K. (2003). The Science of Color (2nd ed.). Oxford, UK: Optical Society of America. p. 350. ISBN 0-444-512-519. 
  • Smal, James; Hilbert, D.S. (1997). Readings on Color, Volume 2: The Science of Color (2nd ed.). Cambridge, Massachusetts: MIT Press. ISBN 0-262-52231-4. 
  • Wyszecki, Günther; Stiles, W.S. (2000). Color Science: Concepts and Methods, Quantitative Data and Formulae (2nd ed.). places: Wiley-Interscience. ISBN 0-471-39918-3. 

External links

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Simple English

, and also those with different types of color blindness.]] People with color blindness[1] cannot tell the difference between certain colors, or they may not see colors at all. Color blindness is the name for a number of medical conditions, and doctors sometimes call color blindness color vision deficiency.

Most color blindness is heritable, usually as simple Mendelian inheritance. More rarely, it may be the result of damage to the eyes, nerves or the brain; it can also happen because the affected person was exposed to certain chemicals. Most color blindness is permanent, but some conditions can also lead to temporary color blindness. During certain kinds of migraine, some people are unable to tell the difference between certain colors. As of 2009, there is no treatment or cure for permanent color blindness.

There are far more males who are color blind than there are females. Between five and eight percent of males, but less than one percent of females, are color blind.[2]

Color blindness is usually thought of as a disability. However, people who are color blind have an advantage: they are sometimes better at seeing through some types of camouflage.[3]

Contents

History

The English chemist John Dalton published the first scientific article about color blindness in 1798, after he found out that he suffered from color blindness himself. The article was called "Extraordinary facts relating to the vision of colours".[4] Because of this, the condition is sometimes called daltonism. As of 2009, the word daltonism is used for only one type of color blindness called red/green color blindness.

Seeing color

In order to understand color blindness, it is necessary to explain how humans (and other animals) can tell the difference between colors. There are three steps:

  1. Electromagnetic waves, commonly known as light, hit specialized nerve cells, called receptors, in the human eye. Some of these are stimulated and generate an electrical signal.
  2. Nerves are used to transport these signals into special parts of the brain.
  3. These parts of the brain interpret the signals they receive. All of these signals are changed into an image. This image is then carefully looked at to separate different objects, to see shapes and sometimes colors, and to link these to other kinds of information.

How the human eye sees colors

Inside the human eye is a part called the retina. The retina receives the images that the eye sees, and sends them to the brain. The retina has two types of cells: Rod cells and Cone cells. They work in different types of light.

  • Rod cells receive the images that the eye sees when the light is dim, at night, or in a dark room.
  • Cone cells, receive the images that the eye sees in normal daylight or in bright light. There are three different types of cone cells. Each type has a different pigment and reacts to a different spectrum of light. One is specially sensitive to short wavelengths, the other to medium wavelengths, and the third to long wavelengths. These wavelengths cover much of the visible light. Each color is "seen" as a result of how much each of the receptors is stimulated.

How the brain works out the colors

Parts of the thalamus and the visual cortex in the brain are involved in seeing, also seeing colors. Color blindness can therefore also result if these areas of the brain, the optic nerve or the retina have been damaged. These types of color blindness usually result from an accident, and are not inherited. Inherited forms of color blindness affect the retina only.

That way it is possible that only a part of the visual field is affected by color blindness, but in the rest, there is no color blindness.

Some types of color blindness, but not inherited color blindness, can be cured.

Causes of color blindness

There are several different problems that can cause color blindness.

  • If a person's eye has no cone cells, then they cannot see any color at all. They can only see shades of dark and light.
  • There are three types of cone cells in the human eye. If there are two types, a person will have a hard time to tell certain colors apart. If there is only one type, a person will not see color at all.
  • Sometimes cone cells change. This means that they no longer react to those wavelengths they should. A person will need more of a certain color to see this color. They see colors differently, and may not be able to tell certain colors apart. Most of these people do not know they are color blind, as they have little difficulty telling colors apart in most cases.
  • There may be nothing wrong with the eye, but the nerves that transport the information or the area in the brain that interprets it may be damaged. This means that the signal is interpreted the wrong way. The damage may be permanent, or it may be temporary. Certain conditions of the brain, like migraine can change the way people see colors.

Different types of color blindness

Total color blindness

This condition is very rare. People who suffer from it can only see differences in levels of brightness and do not see color.[5] This is called monochromacy.[5]

There are two main types of total color blindness:

  1. Rod monochromacy: The retina has no cone cells. This makes it difficult to see even lights of a normal level; this means that people who suffer from it, are almost blind. It occurs almost only on the island of Pingelap, a part of the Pohnpei state in the Federated States of Micronesia. There it is called maskun: about one person in 12 of the population has it. The island was hit by a storm in the 18th century. Very few men survived the storm. One of them carried a gene for rod monochromacy. Today, several hundred people live on the island, about 30% have this gene.
  2. Cone monochromacy: The retina has both rods and cones, but only one type kind of cone. People who suffer from this will be able to see patterns well, in normal daylight, but they will not see hues.

Red/green color blindness

Red-green color blindness is the most common form of color blindness, between five and ten percent of males suffer from it. Those affected have trouble telling the difference between red and green. Most often, this is because they lack the receptors for long or medium-length light waves or because these receptors have changed their sensitivity.

Blue/yellow color blindness

Blue-yellow color blindness means that those affected cannot tell the difference between blue and yellow. It is different from the other types of color blindness because it is not linked to sex. It affects both sexes equally. It occurs because those affected lack the receptor for short wavelengths, or because these receptors changed their sensitivity.

Other causes of color blindness

Sometimes, people do not have problems seeing color, but their brain has trouble "telling" the color, and interprets it wrong. It is also possible that only certain parts of the eye have color blindness; people may become color blind because of other diseases, but after the disease goes away, see normally again. This seems to be the case with certain forms of migraine.

How color blindness is inherited

Males have one X and one Y chromosome; females have two X chromosomes. Many of the genes involved in making color vision work are on the X chromosome. For this reason, men are more often affected by color blindness than women.

The "color blind" gene allows non-color blind people see the difference between red and green. The gene is located on the X chromosome. This means that a male will be color blind if the single X he inherits from his mother contains the color blind version of the "color blind" gene. A female will inherit color blindness only if she inherits two X chromosomes containing defective "color blind" genes. In other words, a female needs to inherit "color blind" genes from both parents in order to be color blind.

Finding out if someone suffers from color blindness

Special tests have been developed. These usually have an image with dots of different colors. People will then see different images (most often Arabic numbers). Those with certain types of color blindness will see different numbers from those not affected by color blindness.

Because many young children have not learned numbers yet, other tests have been developed. They use symbols, like a square, a circle or a car instead of numbers.

Design changes

A color code is when there is much information in the color of certain item. Such codes cannot be understood easily by those who are color blind. For this reason, color should not be used alone to give information. Good graphic design avoids using color coding or color differences alone to give information. This does not only help color blind people, but also normally sighted people.

Cascading Style Sheets can be used on web pages. They allow to give a different color scheme for color blind people. Certain color scheme generators help graphic designers see color schemes as eight types of color blind people see them.[6]

Color blindness is very sensitive to changes in material. A red-green color blind person may be unable to see the difference between colors on a map printed on paper. The same map on a computer screen or television may appear normally. In addition, some color blind people find it easier to tell the difference between colors on artificial materials, such as plastic or in acrylic paints, than on natural materials, such as paper or wood. Thirdly, for some color blind people, color can only be distinguished if there is enough color: thin lines might appear black, but a thicker line of the same color can be seen in the correct color.

File:Not-Aus Betä
Kill switches such as this one have to follow very specific design rules. These rules include what colors to use.

In certain cases when it is important to understand information very quickly, the visual system may drop the colors, and only work in shades of gray. This is important to know when designing the interfaces for objects that need to be used in an emergency situation, like emergency brakes, or emergency phones.

Because color blind people may not see the difference between colors such as red and green, some countries, such as Romania have refused to give them driving licenses. In Romania, people have started to change the laws so that color blind people will also be able drive legally.[7]

In the United Kingdom, electricity wires in houses used to be red, black and green. They were changed to brown, blue and green/yellow to help color blind people see the difference between the "live" and "earth" wires.[8]

What color blindness is not

Many people do not understand color blindness. People who are color blind never swap the colors they are blind to. They may have trouble telling two colors from one another. That way they may have a problem finding the right kind of apple in the supermarket. The image below first shows the way that two apples look to a person with normal vision, and then the way it looks to a person with red-green color blindness. The left apple is a Braeburn; it is red in color. The apple on the right is a Granny Smith; it is green. To someone with red-green blindness, the apples look like they are almost the same color.

References

  1. U.S. spelling; British spelling is colour blindness.
  2. Sharpe, LT; Stockman A, Jägle H, Nathans J (1999). "Opsin genes, cone photopigments, color vision and color blindness". In Gegenfurtner KR, Sharpe LT. Color vision: from genes to perception. Cambridge University Press. ISBN 9780521004398. http://books.google.com/books?id=4zQMQLLVkFYC. 
  3. Morgan MJ, Adam A, Mollon JD. "Dichromats detect colour-camouflaged objects that are not detected by trichromats." Proc Biol Sci. 1992 Jun 22;248(1323):291-5. PMID 1354367.
  4. Dalton J, 1798 "Extraordinary facts relating to the vision of colours: with observations" Memoirs of the Literary and Philosophical Society of Manchester 5 28-45
  5. 5.0 5.1 Byrne A, Hilbert D. "A Glossary of Color Science." Originally published in Readings on Color, Volume 2: The Science of Color. (MIT Press, 1997). Accessed November 7, 2006.
  6. Color Scheme Designer. For an example of a map that could present a significant problem to a color blind reader, see this graphic from a New York Times article. The typical red-green color blind reader will have a lot of difficulty telling the green sections from the orange ones. This makes the graphic unreadable.
  7. "Petition to European Union on Colorblind’s condition in Romania". http://discromat.wordpress.com/2007/08/15/time-out/. Retrieved 2007-08-21. 
  8. "BBC h2g2 - Colour Blindness". http://www.bbc.co.uk/dna/h2g2/A883523. Retrieved 2009-04-17. 


Citable sentences

Up to date as of December 29, 2010

Here are sentences from other pages on Color blindness, which are similar to those in the above article.








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