achromatopsia (redirected from Rod monochromacy)

achromatopsia /achro·ma·top·sia/ (ah-kro″mah-top´se-ah) monochromatic vision.

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a·chro·ma·top·si·a (-krm-tps-, -kr-) or a·chro·ma·top·sy (-krm-tps, -kr-)

n.

A severe congenital deficiency in color perception, often associated with nystagmus and reduced visual acuity. Also called achromatic vision, monochromatism.

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Achromatopsia

The inability to distinguish any colors.

Mentioned in: Color Blindness

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achromatopsia.

See color blindness.

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achromatopsia (krōmtōp´sē),

n the condition of total color blindness.

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Achromatopsia 

Total colour blindness. The majority of cases are autosomal recessively inherited and caused by a mutation in genes CNGA3, CNGB3 and CNAT2. There are two types of achromatopsia. Complete achromatopsia which results from having only rods and no functional cones (rod monochromat) have photophobia, poor acuity and nystagmus. Incomplete achromatopsia in which there are the same symptoms, but in a diminished form. Patients benefit from dark tinted lenses. Achromatopsia is non-progressive and very rare: one person in about 35 000 people. A few cases may be acquired resulting from a lesion in cortical area V4 (central achromatopsia). Syn. achromasia; achromatic vision; achromatism; acritochromacy; monochromatism. See defective colour vision; hemiachromatopsia; monochromat.