23 Facts About Color Blindness

Color blindness also known as color vision deficiency (CVD) is a condition where you don’t see colors in the traditional way. This can happen if certain cells known as photoreceptors, or more specifically cones, in your eyes are missing or not working correctly. These cones typically allow you to see each color on the rainbow. If you have color blindness, you might not see each of these colors.

Don’t confuse color blindness with a type of blindness (a condition where you have limited or no sight) color blindness is simply a change in the way your eyes see color.

We all see a continuum (range) of colors, but which ones we see depends on how well our photoreceptors function. Photoreceptors are cells within your eyes that respond to specific wavelengths of light. Everyone sees color slightly differently, and the way we see colors may also change as we age if we develop certain age-related eye conditions such as cataracts.

Why do we see different colors?

When we see different colors, what we’re really perceiving is different wavelengths of light. Your eyes contain photoreceptors (cells) that process light entering the eye to help you perceive color. Rods detect differences between dark and light. Cone cells detect colors when lighting conditions are bright enough. Each wavelength corresponds to a different shade in the visible spectrum of light. Reds are the longest wavelengths, greens are medium and blues are the shortest.

The world of color vision is full of intricacies and interesting facts. 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.

Genetics of Color Blindness

1. It’s estimated that there are 300 million color blind people in the world!

2. Color blindness is more common than you might think! 1 in 12 men is color blind while only 1 in 200 women have the condition. This means that 95% of the color blind community are men. 98% of those with color blindness have red-green color blindness.

3. Red-green color blindness is passed down through the mother on the X-chromosome. However, there are different ways the “color blindness gene” can show up! Learn more about how color blindness is passed down.

4. Red-green color blindness is common name for the two most common types called Deutan and Protan. It is given this name since red and green are the two colors that are typically most difficult to distinguish by color blind individuals with either of these conditions. Learn more about the types of color blindness.

5. Red-green color blindness is caused by a defect in a person’s light-sensitive cone cells. The green-sensing M cone and the red-sensing L cone’s sensitivities overlap more than they would in a normally-sighted person’s eyes, which creates color confusion across the spectrum.

6. Babies are born color blind! As they grow, their color vision improves and is typically fully developed by the age of 6 months.

7. It’s possible to be color blind in one eye and have normal color vision in the other. This is called unilateral dichromacy and it’s very rare.¹

8. John Dalton, a scientist, wrote the first paper on color blindness in 1794. He believed his own color blindness was caused by a discoloration in his aqueous humor - learn more about John Dalton.

9. On the atoll of Pingelap in the Pacific Ocean, 4.9% of the population has achromatopsia or complete color blindness. In the US, only .0003% of the population has the same condition.²

10. People who are red-green color blind are often surprised to find out that peanut butter is NOT green!

Animals and Color Vision

11. The mantis shrimp has 12 types of cone cells, 4 times as many as humans! Scientists aren’t sure why they have such a complex visual system yet, but it is known that the animal can see infrared and ultraviolet light. Learn more about marine animals’ color vision in our blog.

12. Contrary to popular belief, dogs don’t actually see in black and white. They are dichromats, which means they have two types of cone cells, and see in mostly blue and yellow. Their vision is somewhat similar to a color blind human’s color vision. Learn more about our furry friends’ color vision.

13. Peacocks are known for their colorful plume of feathers that are dazzling to humans. However, what’s most important to peacocks is the number of eye-shaped marks on the ends of the feathers. Peacocks see these ‘eyes’ in ultraviolet light, so the more eyes a male peacock has, the more attractive it is as a mate.

Color Blind Test Facts

14. Online color vision test used by more than 1 million people worldwide. It is the first test of its kind, designed to identify different types and severity of color blindness. A properly administered color blindness test requires that one not wear filtered lenses or glasses, including color blind glasses. Take the color vision test..

15. The Ishihara color blind test was invented by Dr. Shinobu Ishihara in 1916 while he held a military position in the Japanese Army. The test was originally developed exclusively for use by the Japanese Army, but became more widespread in 1917.

Color Blind Problems

Color blindness can cause some unique problems in a color blind person’s life that occur in everyday situations that non-color blind people might take for granted. Here’s a list of just some of the issues it can cause:

16. In Romania, people who are color blind are not allowed to obtain a driver’s license.

17. In some countries, there are barriers to entry in certain professionals for people who are color blind. In England, color blindness may prevent you from becoming a doctor; in the US one cannot get a pilot’s license; and in many parts of the world, it’s difficult to become an electrician.³

18. 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!

19. People who are color blind often have trouble cooking meat to the proper temperature. Much of the process relies on monitoring the meat’s color and they cannot distinguish between the shades of cooked and uncooked meat.

20. 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 or 3 colors: blue and yellow.

21. 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.

22. Many color blind people struggle to match their black and blue socks and can find themselves a little mismatched from time to time. Read more about what color blind people see.

Famous Color Blind People

23. Some of your favorite celebrities may be color blind! There are many public figures with color blindness, here’s a list of a few:

• Robert Redford - American actor
• Sting - British musician
• George Clinton - American musician
• Jack Nicklaus - American professional golfer
• Howie Mandel - American entertainer
• Eddie Redmayne - British actor
• Prince William - Prince of England, Duke of Cambridge
• Meat Loaf - American musician
• Mark Zuckerberg - Facebook CEO and founder
• Christopher Nolan - English director
• Fred Rogers - American television actor, host of Mr. Rogers
• Bing Crosby - American musician
• Chris Rogers - Australian cricketer