Medical Definition of achromatopsia
: a visual defect that is marked by total color blindness in which the colors of the spectrum are seen as tones of white, gray, and black, by poor visual acuity, and by extreme sensitivity to bright light
achromatope\ˌā-ˈkrō-mə-ˌtōp\ play noun What was far more disabling was the painful hypersensitivity to light and poor visual acuity which also affect congenital achromatopes.—Oliver Sacks, The Island of the Colorblind, 1997
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