Color Blindness

Article written by Joan Connelly, Equity Data Analyst

According to the National Eye institute, humans can have defects in photopigments responsible for responding to blue, green, and red light. Most people have normal color vision, or trichrome, in which all three types of light cones in the eyes are used. However, there are inherited color deficiencies that cause certain colors to look like others, or not be seen at all. The most common color deficiency is deuteranomaly, which makes yellow and green appear more red, followed by protanomaly, which makes red, orange, and yellow appear more green. The most rare form of color-blindness is blue-yellow, or tritanopia, where blue appears green and yellow appears violet or light grey[1]. A whopping 300 million people are affected by colorblindness, and it is more common in men. It is estimated that as many as 8% of men are affected by the deficiency, while only about 0.5% of women are affected[2]. This means that you likely know a person who views colors differently due to some type of color blindness!

For many of our visitors, data visualizations may be incredibly difficult to understand due to an inability to distinguish between certain colors. To bypass this barrier and make our website more accessible to a wider audience, we have implemented color palettes into our graphs and other visualizations that are easily detectable to those with color vision deficiencies.

To check out one of our color-deficiency friendly graphs, click here.

Participation Opportunity!

If you are color blind and are willing to participate in a study at the Medical College of Wisconsin’s Eye Institute, see details through the link below! Participants will be compensated $15 an hour.


To understand just how much this color deficiency can impact your life, check out these great websites! Input any url to see what it would look like with various color deficiencies. compares 8 types of color blindness with trichromacy.


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