Color Blindness and Color Vision Deficiency

Short: Color blindness, more precisely color vision deficiency, mainly affects distinguishing red and green tones and is usually genetic. Men are affected far more often than women, since the underlying gene defect is on the X chromosome.

In more detail: True complete color blindness, where no colors at all are perceived, is extremely rare.

In detail

• Red-green deficiency: The most common form affects about 8 percent of men and less than 1 percent of women worldwide.
• Cause: The retina contains three cone types for red, green, and blue; if one is missing or malfunctions, color vision disorders occur.
• Inheritance: Since the gene in question is on the X chromosome, mothers often pass the predisposition to their sons without being affected themselves.
• Ishihara test: Special dot patterns with embedded numbers are used to diagnose red-green deficiency.
• Everyday impact: Affected people can usually still distinguish traffic lights, since position and brightness provide additional cues.
• Professional restrictions: Certain professions like pilot or electrician sometimes have color vision requirements for safety reasons.
• Aids: Special color filter glasses or apps can make distinguishing certain shades easier for some affected people, but they don’t cure the underlying cause (haut-aufbau-und-funktionen, nervensystem-aufbau-und-funktion).