Color blindness

Lore & Background

Color blindness is typically classified using the von Kries classifications, based on severity and affected cone. Total color blindness (monochromacy) is much less common than partial color blindness. Partial color blindness includes dichromacy and anomalous trichromacy, often clinically defined as mild, moderate, or strong. Monochromacy includes rod monochromacy (complete achromatopsia) and blue cone monochromacy, the latter caused by lack of functionality of L and M cones and linked to the X chromosome. Dichromats can match any color with a mixture of just two primary colors; types include protanopia, deuteranopia, and tritanopia. Anomalous trichromacy is the mildest type, with severity ranging from almost dichromacy to almost normal trichromacy.

Reader's Guide

Color blindness has significant implications for daily life and career eligibility. Depending on jurisdiction, color blind people are ineligible for careers such as aircraft pilots, train drivers, police officers, firefighters, and members of the armed forces. Diagnosis is usually done with a color vision test like the Ishihara test. There is no cure for most causes, though research into gene therapy for severe conditions is ongoing. Minor forms do not significantly affect daily life, and individuals develop adaptations and coping mechanisms. Color blind glasses may help with some color tasks but do not grant normal color vision. Mobile apps can use a device's camera to identify colors. The effect on artistic ability is controversial, but a number of famous artists are believed to have been color blind. The condition is more prevalent in males due to X-chromosome-linked opsin genes.

Did You Know?

• Color blindness can result from physical or chemical damage to the eye, the optic nerve, parts of the brain, or from medication toxicity.
• Color blind glasses may help the red–green color blind at some color tasks, but they do not grant the wearer 'normal color vision' or the ability to see 'new' colors.
• Depending on the jurisdiction, color blind people are ineligible for certain careers, such as aircraft pilots, train drivers, police officers, firefighters, and members of the armed forces.