Monochromacy

This article is about single color vision. For colour deficiency as one component of a multi-symptom heritable syndrome in humans, see achromatopsia.
"Monochromat" redirects here. For the chemical ion species, see Monochromate.
Monochromacy
Monochromacy is a disease state in human vision but is normal in pinnipeds (such as Neophoca cinerea shown here), cetaceans, owl monkeys and some other animals.
SpecialtyOphthalmology

Monochromacy (from Greek mono, meaning "one" and chromo, meaning "color") is the ability of organisms to perceive only light intensity without respect to spectral composition. Organisms with monochromacy lack color vision and can only see in shades of grey ranging from black to white. Organisms with monochromacy are called monochromats. Many mammals, such as cetaceans, the owl monkey and the Australian sea lion are monochromats. In humans, monochromacy is one among several other symptoms of severe inherited or acquired diseases, including achromatopsia or blue cone monochromacy, together affecting about 1 in 30,000 people.