deuteranopi

Deuteranopia, also called deuteranopi, is a color vision deficiency characterized by the absence of functional medium-wavelength (M) cone photoreceptors in the retina. As a result, individuals have difficulty distinguishing red from green hues and may perceive certain colors as muted or indistinguishable. The condition is a form of red-green color blindness and is distinct from deuteranomaly, in which M-cone sensitivity is altered but not absent.

Pathophysiology and inheritance: Deuteranopia is typically inherited in an X-linked recessive pattern, making it more common in males. It arises from genetic changes that affect the opsin pigment produced by the M-cone cells on the X chromosome, while L-cone and S-cone function may be normal. Because the condition is congenital, most people are born with it and do not lose color vision later in life.

Symptoms and functional impact: The primary feature is difficulty differentiating greens and reds, which can extend to related hues such as browns and purples in certain lighting. Brightness and context often help compensate, but color cues important in activities like driving, design, and some occupations may require alternative strategies. Color perception is not uniformly degraded across all tasks; many colors remain identifiable, and blue-yellow discrimination is typically preserved.

Diagnosis: Color vision testing, including Ishihara plates and anomaloscope assessments, is used to diagnose deuteranopia and distinguish it from other color vision deficiencies. A comprehensive eye exam can rule out other retinal conditions.

Management: There is no cure. People adapt by relying on non-color cues and routines. Some color-correcting lenses or digital tools can aid certain tasks for some individuals, but results vary and do not restore normal color vision. Awareness and accommodations in education and work can help mitigate practical challenges.