deuteranope

Deuteranopia is a form of red-green color vision deficiency characterized by the absence or malfunction of the medium-wavelength (M) cone cells in the retina. People with deuteranopia have difficulty distinguishing greens from reds and browns because green hues do not appear as they do to people with normal color vision. Greens may look instead like beige, gray, or pale yellow, and some color contrasts are reduced.

Genetically, deuteranopia is typically inherited in an X-linked recessive manner. The condition mostly affects males, while females are usually carriers who do not show full symptoms; on rare occasions, females can be affected due to X-inactivation patterns.

Prevalence varies by population but is estimated to affect about 1% of men of Northern European ancestry; deuteranomaly, a milder red-green deficiency, is more common. Diagnosis is usually made with standardized color vision tests such as Ishihara plates or anomaloscope testing, often during childhood or routine eye exams.

Impact on daily life can include challenges with color-coded information (maps, graphs, electrical wiring, or traffic signals). People with deuteranopia can often accomplish tasks by relying on position, brightness, luminance cues, or textual labels rather than color alone.

There is no cure. Coping strategies emphasize accessible design, high-contrast color schemes, and explicit labeling. Some wearable or digital color filters claim to improve discrimination for certain tasks, but results vary and they are not universally effective.

Related conditions include protanopia (absent L-cones) and deuteranomaly (weaker M-cones), both part of the broader spectrum of red-green color vision deficiencies.