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Color Blindness

Color blindness, also known as color vision deficiency, is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions.  5 to 8% of the men and 0.5% of the women of the world are born colorblind.  

Inside our eyes, there are 3 different types of cone cells which are sensitive to one of three wavelengths of light: red (long), green (middle), and blue (short).  Color blindness occurs when one or more of someone’s cones are either missing or absorbing light abnormally. 

Based on clinical appearance, color blindness may be described as total or partial. Total color blindness is much less common than partial color blindness.

There are two major types of color blindness: those who have difficulty distinguishing between red and green, and who have difficulty distinguishing between blue and yellow.

Types of color vision deficiency

• Monochromatism: Either no cones available or just one type of them.
• Dichromatism: Only two different cone types, the third one is missing completely.
• Anomalous trichromatism: All three types but with shifted peaks of sensitivity for one of them. This results in a smaller color spectrum.

Dichromats and anomalous trichromats exist in 3 different types according to the missing or malfunctioning cone:

• Tritanopia/Tritanomaly: Missing/malfunctioning S-cone (blue)
• Deuteranopia/Deuteranomaly: Missing/malfunctioning M-cone (green)
• Protanopia/Protanomaly: Missing/malfunctioning L-cone (red)

Further Reading, Videos, Sources

• Color Blindness – Wikipedia
• What is Colorblindness? – Color Vision Testing
• Colorblind Population – Colblindor
• Types of Color Blindness – Colblindor
• No Such Thing As Color – What it’s like to be color blind (Youtube)
• What is Color Blindness | Signs and Symptoms (Youtube)