Colorblindness

Colorblindness is a specific visual disability where the user may (or may not) be able to clearly see, but they are unable to fully perceive the color in what they see. Approximately 4.5% of the world population have some form of colorblindness (also called color vision deficiency, or CVD). it affects 1 in 12 men and 1 in 200 women. These figures are higher for white (Caucasian) people or others who have mixed grace genes in their genetic history.  By the math, at least one of your co-workers is color blind. For the vast majority of people, the condition was inherited from their mother, but others may become colorblind from other diseases such as diabetes and multiple sclerosis, or from aging or certain medications. As many as 3% of the population could be affected by age-related deficiencies. More than a few kinds of colorblindness exist, each with its own challenges.

• Protanomaly is a reduced sensitivity to red light (1% of men). Protanopia is the total inability to see red (1% of men).
• Deuteranomaly is a reduced sense of green light (and the most common form of colorblindness, 5% of men). Deuteranopia is the total inability to see green (1% of men).
• Tritanomaly is a reduced sensitivity to blue light (and is extremely rare). Tritanopia is the total inability to see blue. (Put together they're about 1 in 30,000-50,000 people.)
• Achromatopsia is the extremely rare (1 in 33,000 people) form of colorblindness where there is no color, only monochromatic (shades of grey) vision.

People with either deuteranomaly or protanomaly are collectively known as red-green colorblind because regardless of which of the two types they have, they have difficulty distinguishing between red and greens, as well as browns and oranges.  They may also confuse blues and purples.

What people with colorblindness have to say

• Color Blind Probs is a Twitter account with a colorblind author who retweets problems other colorblind people have navigating the world.
• On Smells and Colors by Dan Brown is about Dan's inability to smell (called anosmia) and his son's colorblindness. Dan compares the challenges that each disability provides, and talks about how his son's struggles have helped him understand both disabilities better.

Tools

• Colorblind Web Page Filter by Toptal
• Check My Colours - will provide feedback on a color palette for colorblind users
• I Want To See Like The Color Blind - will provide colorblindness filters through Chrome.
• Color Oracle - a colorblindness simulator for Windows, Mac, and Linux
• Colorsafe provides accessible color palettes using a web tool

Colorblindness in animals

Can dogs see colors? by Colblindor

Additional Resources

• Responding to Color by the Cooperative Extension Service of the University of Kentucky.
• Color Blind Awareness website provides information on colorblindness including types of colorblindness.