What Causes Color Blindness?

Sensitivity to colors may diminish due to macular degeneration.
Blue is made of short wavelengths, and its perception is sometimes affected by color blindness.
The human eye detects color with photoreceptors located on the retina at the back of the eye.
With color blindness, red and green traffic lights might look like the same color.
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  • Written By: R. Kayne
  • Edited By: Niki Foster
  • Last Modified Date: 30 September 2014
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Color blindness is most often a genetic visual deficiency that limits the colors that an individual can detect. Most people with this condition don't only see in black and white. The colors affected are usually limited to green and red, which often appear as shades of tan or brown. Less often, the color blue may also be affected.

The human eye detects color with photoreceptors located on the retina at the back of the eye. These photoreceptors come in two types, rods and cones. Rods fill the peripheral edges of the retina and are used in low-light conditions, such as in night vision. Rods do not detect color well, but allow people to see in the dark.

Cones appear throughout the retina and contain pigments that are responsive to certain colors. The pigments communicate with the brain when fired. This is how a person detects color. Cones require brighter light to function than do rods, which is why we cannot see colors well in the dark.

Color blindness is a result of certain cones misinterpreting the wavelengths that correspond to their respective colors. Red, green and blue colors have corresponding wavelengths. Red wavelengths are longest, green colors generate medium wavelengths, and blue colors are made of shorter wavelengths. If the green cones, for example, only respond to slightly longer wavelengths, green will be interpreted by the brain as red.

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There is no cure for color blindness, but it is usually not an inhibiting condition. Red and green traffic lights might appear to be similar shades of the same color, but those who are color blind use the light’s position as an indicator of when to stop or go. Color blindness becomes more of an issue if work demands color separation. This might be the case for an artist or a designer, for example, or for an electrician who must see red, green and yellow wiring schemes.

Studies suggest about eight percent of the world’s male population is genetically color blind, while less than one percent of the female population is affected. In addition to genetic inheritance, certain diseases or damage to the eyes can cause color blindness. As people age, sensitivity to colors may diminish due to macular degeneration, cataracts or other conditions.

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Discuss this Article

anon266241
Post 16

How much would you pay to see the missing color? By the way, I'm red-green colorblind and it ticks me off that there is a rich red color I am missing out on. I only realized this when I used various color filters on my computer screen.

anon265071
Post 15

I think I know the answer to my own question, but my father is red green colourblind and my brother is not, but I am interested in finding if my sister and I (female) both are carriers for colourblindness and possibly will give our children colourblindness as well as my father?

I'm a creative person and I wouldn't like my own kids to feel they couldn't do anything in art because they are colourblind. Can you maybe explain this a little?

anon238292
Post 14

I am colour blind in red-green colour blindness. I have one son. Will he also suffer from red-green colour blindness? Please reply.

anon175664
Post 12

Is there a chance that stress can cause color blindness?

anon165973
Post 11

It's because females have two X chromosomes and males only have one. Since it's an X linked recessive disorder a male would only need one recessive gene to have the disease whereas a female would need two.

Females could have one dominant gene and one recessive therefore being a carrier of the disease, but not showing the side effects.

anon162885
Post 10

anon101557iIs right. Also 3/150 would not be presented this way, as it has not fully been reduced, and if presented statistically would be shown as 1/50. This seems to indicate that you made up the statistic.

anon101557
Post 8

Pertaining to anon22449 statement that three out of 150 males are color deficient, that statement is false. The data supports that one out of every 12 males and one out of every 250 females has some type of color vision deficiencies.

An abundant amount of valid information pertaining to color vision deficiencies can be found online The information from the website comes from Dr. Terrace L. Waggoner, a color vision expert.

anon70272
Post 7

it is not that color blindness doesn't occur in the female.

anon49887
Post 5

this is because a female's chromosomes are XX and males are XY so a female could have a 'faulty' X and a 'normal' X. males are XY so the female could pass on the faulty X to her son, then he does not have another X to cancel it out or 'back it up,' whereas a female will have another X.

anon22449
Post 2

this is because males are XY and men only need one recessive allele to become colorblind as in women since they have XX they need to recessive alleles from their parents to become colorblind. i believe 3 out of 150 men are colorblind.

anon13752
Post 1

i have read an article about colour blindness and it said that colour blindness occurs mainly in males. Why is this so?

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