Deuteranopia Simulation: Green-Blind Vision

Deuteranopia is a type of color vision deficiency caused by the complete absence of medium-wavelength (green) cone photoreceptors. It is the more common of the two main red-green color blindness types, affecting approximately 1% of males worldwide. Like protanopia, it follows an X-linked recessive inheritance pattern, making it far more prevalent in males than females. People with deuteranopia rely on only long-wavelength (red) and short-wavelength (blue) cones to perceive color.

While both deuteranopia and protanopia are red-green color blindness, they produce slightly different color perceptions. In deuteranopia, red colors retain more of their brightness compared to protanopia, where reds appear significantly darker. Greens in deuteranopia tend to shift toward beige or tan rather than the yellow seen in protanopia. The practical differences can be subtle, and both conditions create similar challenges with red-green discrimination. However, the distinction matters for accurate diagnosis and for understanding which specific wavelengths are most affected.

Deuteranopia and its milder variant deuteranomaly together account for the majority of all color vision deficiencies. Deuteranomaly alone affects about 5% of males, making it the single most common type of color blindness. The gene responsible for green cone production is located on the X chromosome, which is why males (with only one X chromosome) are far more likely to be affected. Women can be carriers without showing symptoms, though in rare cases they can be affected if both X chromosomes carry the variant. Some populations show higher rates than others, with Northern European males having rates up to 8% for all red-green deficiencies combined.

Deuteranopia affects many practical tasks that rely on color discrimination. Reading color-coded maps, charts, and graphs can be challenging when reds and greens are used as opposing categories. Status indicators on electronics — like red for error and green for success — may be indistinguishable. Selecting ripe produce, matching clothing colors, and interpreting warning signs can all be affected. Many people with deuteranopia are unaware of the extent of their deficiency until they are formally tested, as they have developed effective compensating strategies throughout their lives.

Designing for deuteranopia follows similar principles as designing for protanopia. Avoid red-green color pairings as the only means of conveying information. Instead, use blue-orange or blue-yellow palettes, and supplement color with text labels, patterns, or icons. In data visualization, colorblind-safe palettes from tools like ColorBrewer are widely available. Many modern operating systems and applications include built-in colorblind modes that adjust the display to improve contrast for people with red-green deficiencies.