Columbia Encyclopedia

Search results

500 results found

color blindness

(Encyclopedia)color blindness, visual defect resulting in the inability to distinguish colors. About 8% of men and 0.5% of women experience some difficulty in color perception. Color blindness is usually an inherit...

blindness

(Encyclopedia)blindness, partial or complete loss of sight. Blindness may be caused by injury, by lesions of the brain or optic nerve, by disease of the cornea or retina, by pathological changes originating in syst...

color

(Encyclopedia)color, effect produced on the eye and its associated nerves by light waves of different wavelength or frequency. Light transmitted from an object to the eye stimulates the different color cones of the...

night blindness

(Encyclopedia)night blindness, inability to see normally in subdued light. It is usually a result of vitamin A deficiency. The rod cells, one of two light-sensitive areas of the retina of the eye, are impaired in t...

river blindness

(Encyclopedia)river blindness or onchocerciasis, disease caused by the parasitic nematode worm Onchocerca volvulus. The worm larvae are transmitted by the bites of blackflies (genus Simulium) that live in fast movi...

color index

(Encyclopedia)color index, in astronomy, difference in an object's brightness as recorded between any two well-defined bands of the electromagnetic spectrum by using optical filters of different colors. If blue and...

color-field painting

(Encyclopedia)color-field painting, abstract art movement that originated in the 1960s. Coming after the abstract expressionism of the 1950s, color-field painting represents a sharp change from the earlier movement...

four-color process

(Encyclopedia)four-color process: see printing. ...

Meryon, Charles

(Encyclopedia)Meryon, Charles shärl mĕryôNˈ [key], 1821–68, French etcher. His short life was saddened by poverty and neglect and complicated by recurring forms of mental aberration. Prevented by color blindn...

vision

(Encyclopedia)CE5 Optic nerve vision, physiological sense of sight by which the form, color, size, movements, and distance of objects are perceived. Defects of vision include astigmatism, color blindness, far...