deuteranopian

Deuteranopian refers to a person who has deuteranopia, a type of red-green color vision deficiency. In deuteranopia, the medium-wavelength cone photoreceptors (M-cones) are absent or nonfunctional, which impairs discrimination between greens and reds. People with this condition often perceive greens as beige or gray and may confuse certain color hues, especially those with similar luminance, such as brown and green. The condition is typically congenital and inherited in an X-linked recessive pattern; it mostly affects males, while females are usually carriers with milder or no symptoms. The underlying genetic basis involves rearrangements or mutations affecting the OPN1MW gene that encodes the M-cone photopigment, though the specific mutation can vary.

Diagnosis is usually by color vision tests such as the Ishihara plates, the Farnsworth-Munsell 100-Hue test, and anomaloscope assessments. Several tests distinguish deuteranopia from deuteranomaly, which is partial M-cone dysfunction. While there is no cure or proven way to restore normal color vision, individuals can adapt with practical strategies: relying on luminance cues, using color-labeling tools, and using colored-tinted lenses or digital color-corrective apps to improve color discrimination in certain tasks. The condition is non-progressive and present from birth.

Prevalence estimates vary by population but are commonly cited as about 5% of males of Northern European ancestry and less common in females. Awareness and accommodations in educational and occupational settings have improved accessibility for those with deuteranopia.