What is "monochromacy"

n. The quality of having only one independent channel for conveying color information in the eye, i.e. total color blindness.

n. complete color blindness; colors can be differentiated only on the basis of brightness [syn: monochromatism, monochromatic vision, monochromia, monochromasy]

Monochromacy (mono meaning one and chromo color) is among organisms or machine the ability to distinguish only one single frequency of the electromagnetic light spectrum. In the physical sense, no source of electromagnetic radiation is purely monochromatic, but can be considered as a gaussian distribution of frequencies shaped around a peak. In the same way a visual system of an organism or a machine cannot be monochromat but will distinguish a continuous set of frequencies around a peak, depending by the intensity of the light. Organisms with monochromacy are called monochromats.

Many species, such as all marine mammals, the owl monkey, and the Australian sea lion (pictured at right) are monochromats under normal conditions. In humans, absence of color discrimination or poor color discrimination is one among several other symptoms of severe inherited or acquired diseases as for example inherited achromatopsia (OMIM 216900 262300 139340 613093), acquired achromatopsia or inherited blue cone monochromacy (OMIM 303700).