7 Fast Facts to Know About Color Blindness

Color vision deficiency affects 300 million people worldwide. This article addresses the types, causes, prevalence, and treatment of color blindness.

By Ability Central

21 May, 2024

Colorful rainbow light shines on the left eye of a smiling young Black woman laying on a white background

There are about 300 million people in the world with color vision deficiency. In this article, Ability Central answers seven frequently asked questions about color blindness. 

  • What is color blindness?
  • What causes color vision deficiency?
  • What are the risk factors for color vision impairment?
  • What are the types of color blindness?
  • How does color blindness affect communication?
  • Is there a treatment or cure for color vision deficiency?
  • Where can I get more information about color blindness?


What is color blindness?

Color blindness is the commonly accepted term for a condition in which a person doesn’t see colors in the traditional way. Most people who are diagnosed with color blindness still see a range of colors, but they see the colors differently than others do, like difficulty seeing the brightness of colors or the difference between shades. 

True color blindness, where everything is seen in shades of gray, is rare.

Color blindness is also called:

  • color vision deficiency
  • poor or deficient color vision
  • color vision impairment


What causes color vision deficiency?

People see color because their eyes have photoreceptors in the retina called cones. These cones have light-sensitive pigments that enable people with traditional color vision to recognize different colors. 

Each cone is sensitive to either red, green, or blue light based on the wavelength of the light. The cones send the information to the brain to interpret various colors. However, when those cones aren’t working correctly, a person is considered color vision deficient or colorblind.


What are the risk factors for color vision impairment?

Most people with color blindness are born with the condition. However, there are ways a person can lose their color vision over time.

Risk factors for color blindness include:

  • Gender. Men are more likely to be born with color blindness than women. An estimated one in ten men have some form of colorblindness.
  • Nationality. Color blindness is more common among people of Northern European descent.
  • Medication. Some drugs like hydroxychloroquine (a medication used to treat rheumatoid arthritis) increase the risk of acquiring colorblindness.
  • Age. Physical changes can occur in the eye to affect a person’s ability to perceive colors. Research shows color vision declines more rapidly after age 70.
  • Other illnesses. A person is more likely to acquire colorblindness if they have 

In some cases, color blindness “acquired” from other conditions can go away when the conditions are treated. 


What are the types of color blindness?

There are three types of color-sensing cones in the eye. They are:

  • Red-sensing cones (L cones) that perceive long wavelengths.
  • Green-sensing cones (M cones) that perceive middle wavelengths.
  • Blue-sensing cones (S cones) that perceive short wavelengths.

When one or more of these cones is damaged or missing, a person’s ability to see color deteriorates. The categories are:

  • Trichromacy: All three types of cones are present and working. 
  • Anomalous trichromacy: All three types of cones are present, but one type isn’t as sensitive as it should be. 
  • Dichromacy: One type of cone is missing. 
  • Monochromacy: You only have one type of cone, or you have no cone function at all. 

Depending on which cones are damaged or missing, a person may have:

  • Red-green color blindness (protan or deuteran color blindness)
  • Blue-yellow color blindness (tritan color blindness)
  • Full color blindness (monochromacy or achromatopsia), which is extremely rare 

To understand more about each type of color vision deficiency and what a person with each kind sees, refer to What Are the Early Signs You Might Be Color Blind?

A chart with photo examples of what the world looks like for different types of color blindness. At the top of the page, underneath Ability Central’s capital A logo, a green oval with white text reads Types of Color Blindness and is followed by nine labeled photos. The first is labeled full color vision and shows a Venice canal against a bright blue sky. The canal has blue boats floating in it and is bordered by bright yellow, green, and red houses. The second is labeled “blue cone monochromacy” and the photo of the canal houses is dim, the colors less vibrant, and with a grayish tinge to the whole image. The third is labeled “achromatopsia” and shows the canal photo in full black and white. The fourth is labeled “tritanomaly” and shows the canal with slightly warped colors: the yellow houses appear orange and the green houses are tinted blue. The fifth is labeled “protanomaly” and shows the canal scene with a bright yellow tint to everything. The red houses appear brown and the green houses are more of a yellow-green, but the blue boats still appear blue. The sixth is labeled “deuteranomaly” and looks similar to the “protanomaly” photo. There is a slight yellow tint to the image and all the colors are weaker. The seventh is labeled “tritanopia” and shows the canal scene washed in pink. The yellow houses appear pink, the green houses appear blue, and the red houses have a pink tint. The seventh is labeled “protanopia” and looks similar to the protanomaly and deuteranomaly photos. Everything is tinted yellow. The red houses appear as dark yellow-brown, the green houses appear bright yellow, and the sky is a darker blue. The ninth and final photo is labeled “deuteranopia” and is also tinted yellow, but much darker. The yellow houses appear gold-brown, the green houses appear brown, and the sky is a darker, weaker blue.

How does color blindness affect communication?

Color blindness, especially undiagnosed, can cause learning difficulties for both school-aged children and adults in the workforce. With so much of our lives taking place online, communication can be difficult for people who are colorblind. 

For example, poor color contrast between text and background makes it difficult to read. Similarly, people with color blindness do not benefit from “color cues,” like color-coded parts of a work presentation or school assignment. 

Plus, a person with color blindness may feel left out or embarrassed compared to someone with full color vision, even more so when color blindness is treated like a joke.

Seeing color is a part of life that many people with traditional vision may take for granted. People who are color-vision deficient may need help with:

  • Knowing if fruits and vegetables are ripe.
  • Interpreting LED indicator lights on devices.
  • The color of a traffic light. 

There are apps that can help people with color vision deficiencies. In addition, Ability Central hosts a collection of mobile devices to help meet your needs. Check out each device listing for its accessibility options.


Is there a treatment or cure for color vision deficiency?

There is no cure for color blindness, but there are treatment options. Most people with color blindness learn to adapt to their surroundings, sometimes through the use of special tools like EnChroma glasses, but mostly by finding ways to understand color without being able to perceive it.

For example, people who are colorblind often do things like labeling medications, relying on smell rather than sight while cooking, and memorizing driving cues (stop signs, stop lights, etc.) based on shape and location rather than color.

To learn more, see The First Steps to Take After Discovering Color Blindness.


Where can I get more information about Color Blindness?

For more information on colorblindness, low vision, and other visual disabilities, see Ability Central’s vision resources, including information about: 

 For color vision-specific information, see:

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