What Is the definition of colorblindness?
It affects every part of our lives. Color is emotional, experiential, and tactical. It gives art life.
It entices us to eat certain foods and buy certain jewelry, and sometimes it literally defines these things. We also use color to interpret information such as signs and lights.
It is deeply ingrained in our basic perception of the world. When the ability to see color is deficient, as in the case of color blindness, there is a dulling of what is seen; or one might say there is a dulling effect in how we see.
Color blindness is a reduced ability to distinguish between colors when compared to the standard for normal human color vision.
When a person is color blind, also called color vision deficiency (CVD), they usually have difficulty distinguishing between certain colors such as yellow and orange, green and brown, pink and gray, or blue and purple.
These confusions are typical of what is called “red-green color blindness,” which includes protan-type CVD (protanomaly and protanopia) and deutan-type CVD (deuteranomaly and deuteranopia).
Red-green color blindness is usually inherited via X-linked recessive genes. Other types of color blindness exist also, such as tritan-type CVD, also called blue-yellow color blindness, which is associated with the inability to see shades of blue, and confusions between blue and green colors.
Blue-yellow color blindness is usually caused by age-related eye conditions such as glaucoma, or exposure to certain chemicals or medical treatments.
In very rare cases, a person can be completely color blind, meaning they see only the intensity of light, but not its color.
This is called monochromacy or achromatopsia. Achromatopsia can be inherited but can also result from progressive eye diseases such as retinitis pigmentosa.
In summary, there are many types and degrees of what can be considered “color blindness,” ranging from partial to complete lack of color discrimination.
To learn if you are color blind, take the EnChroma Color Blind Test. If you have color blindness, our test can tell you your type of color vision and if your color vision deficiency is mild, moderate, or strong — in less than two minutes.
What Do Color Blind People See?
Many assume because of its name that “color blind” means a person can only see in black and white. In actuality, the vast majority of people with color blindness do see color, but they see a much smaller range of shades of color compared to a person with normal color vision.
In addition, a person with color blindness may miss out on details or not notice objects that would normally be plainly visible, because the color of the details or object is confusingly similar to surrounding visual context.
- A classic example is not noticing a ripe red apple in a tree when it is surrounded by green leaves.
- Humans have three primary types of light receptor cells in the retina that respond broadly to red, green, and blue light.
- Signals from these receptor cells form the basis of color vision, by transmitting neural signals to the brain about the relative amount of each primary color to the visual cortex.
- It is estimated that the human visual cortex can perceive about 100 levels of sensitivity for each primary channel: 100 x 100 x 100 = 1 million, which is where we get to 1 million perceived shades of distinct color.
- However, if a person is color blind, for example having red-green color blindness, then the red and green primary channels have an overlap in their signals causing the channels to contain almost the same information.
- In the most extreme case, called dichromacy, the red and green channels are completely indistinguishable, such that the total number of colors that can be seen is just 100 x 100 = 10 thousand or just 1% of the normal range.
- Most people with color blindness have only a partial loss of sensitivity, meaning the information is there, but is harder to notice.
- Depending on the severity, the number of unique shades of color that can be seen is more often estimated to be around 10% of normal.
How Many People are Color Blind?
- There are an estimated 350 million people in the world with red-green color blindness (deutan-type and protan-type vision deficiency), or 4% of the total population.
- Red-green color blindness is acquired genetically through your parents and is expressed by genes on the X-chromosome.
- Because of the X-linked recessive biology behind red-green color blindness, the condition affects mainly men: about one in 12 men (8%), but also includes about one in 200 women (.5%). Read more about the genetics of color blindness.
- Less precise statistics are known about blue-yellow color deficiency, which is most often caused by progressive or age-related eye conditions.
- Some estimates place the total number at least as high as those for red-green color blindness, and may be increasing due to the trend toward an aging population demographic worldwide.
- The more rare forms of color blindness include achromatopsia and progressive eye diseases, such as retinitis pigmentosa.
- Estimates of these conditions are about 1 in 2000 people, or lower, but are known to be greater in certain subpopulations.
What are the some Fun Facts About Color Blindness?
The world of color vision is full of intricacies and interesting facts. At EnChroma, we want you to know everything there is to know about being color blind. So here’s a list of some of the most fun facts we know about color blindness.
Babies are born color blind! As they grow, their color vision improves and is typically fully developed by the age of 6 months. Overall color discrimination capability reaches its peak by age 20, and then starts to decline again.
Dogs & Color Blindness: Contrary to popular belief, dogs don’t actually see in black and white. Dogs are dichromats, which means they have two types of cone cells, and see in mostly blue and yellow.
Their vision is somewhat similar to that of a person with protanopia. Learn more about our furry friends’ color vision.
People who are red-green color blind are often surprised to find out that peanut butter is NOT green! Green and brown is a common color confusion that seems to be particularly relevant to the shade of peanut butter.
Also, because color blind people have a hard time distinguishing between green and yellow, they often have a hard time knowing when a banana is ripe. Many are accustomed to the bitter taste of an unripe banana!
To the normally sighted person, a rainbow features all the colors of the rainbow. For many color blind people, however, a rainbow only appears to have 2 bands of color: blue and yellow.
To a color blind person, the green light on a stoplight may appear white or even blue, while the red and yellow lights may look similar to each other.
Which Test Should You perform to test colorblindness?
If you or a family member are having problems recognizing or distinguishing between colors that other people seem to see, it’s easy enough to determine whether you are color blind without visiting a doctor.
The Color Blind Test is an online color blind test designed to estimate the type and level of color blindness. Created by EnChroma, an independent company based in California, the EnChroma color blind test is the #1 online color blind tool for color vision deficiency that has so far been taken by more than one million people worldwide.
The EnChroma test is based on the classic and widely-used Ishihara “hidden digit” test method and is combined with a computer-adaptive algorithm to measure the type and level of color vision deficiency (CVD). It is available in a numbers mode for adults and children ages 10+ and in a shape mode for kids ages 5+.
The Ishihara test for color blindness is named after a Japanese ophthalmologist Shinobu Ishihara who invented the test for the Japanese army in 1917.
Ishihara has been a good screening test, but it is 100 years old and does not leverage the benefits of today’s computer-based adaptive testing protocols.
The EnChroma test deters memorization and cheating and can be self-administered on a phone or laptop.
Testing children for color blindness poses unique challenges. Color vision develops early in infancy, but until a child can name colors or numbers it is challenging for a parent, teacher or eye care professional (ECP) to learn if a child is color vision deficient (CVD).
As a result, many children with color blindness go undiagnosed. To solve this problem, EnChroma introduced in 2019 a Kids Color Blindness Test that enables younger children to take the test in “shape mode,” in which identifying simple geometric shapes (square, circle, triangle) replace the standard numeric symbols.