| vision | 1. <ophthalmology> The act or faculty of seeing, sight. 2. <psychiatry> An apparition, a subjective sensation of vision not elicited by actual visual stimuli. 3. Visual acuity, symbol V. Origin: L. Visio (18 Nov 1997) |
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| vision disorders | Visual impairment limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, colour vision, or peripheral vision. Visual disability refers to inability of the individual to perform specific visual tasks, such as reading, writing, orientation, or traveling unaided. It is to be differentiated from eye diseases which are restricted to diseases of the eye, the organ and its anatomical parts. (12 Dec 1998) |
| vision disparity | The difference between two images on the retina when looking at a visual stimulus. This occurs since the two retinas do not have the same view of the stimulus because of the location of our eyes. Thus the left eye does not get exactly the same view as the right eye. (12 Dec 1998) |
| vision screening | Application of tests and examinations to identify visual defects or vision disorders occurring in specific populations, as in school children, the elderly, etc. It is differentiated from vision tests, which are given to evaluate/measure individual visual performance not related to a specific population. (12 Dec 1998) |
| vision, binocular | The blending of separate images seen by each eye into one composite image. (12 Dec 1998) |
| vision, entoptic | Visual sensation due to shadows or optical effects of structures within the eye or to excitation of the receptor system by stimuli other than light. (12 Dec 1998) |
| vision, monocular | Vision with one eye or the affecting of one eye. (12 Dec 1998) |
| vision, subnormal | Vision considered to be inferior to normal vision as represented by accepted standards of acuity, field of vision, or motility. (12 Dec 1998) |
| visional | Of or pertaining to a vision. Source: Websters Dictionary (01 Mar 1998) |
| visionariness | The quality or state of being visionary. Source: Websters Dictionary (01 Mar 1998) |
| visionary | 1. Of or pertaining to a visions or visions; characterised by, appropriate to, or favorable for, visions. "The visionary hour When musing midnight reigns." (Thomson) 2. Affected by phantoms; disposed to receive impressions on the imagination; given to reverie; apt to receive, and act upon, fancies as if they were realities. "Or lull to rest the visionary maid." (Pope) 3. Existing in imagination only; not real; fanciful; imaginary; having no solid foundation; as, visionary prospect; a visionary scheme or project. Synonym: Fanciful, fantastic, unreal. See Fanciful. Origin: Cf. F. Visionnaire. 1. One whose imagination is disturbed; one who sees visions or phantoms. 2. One whose imagination overpowers his reason and controls his judgment; an unpractical schemer; one who builds castles in the air; a daydreamer. Source: Websters Dictionary (01 Mar 1998) |
| visioned | Having the power of seeing visions; inspired; also, seen in visions. Source: Websters Dictionary (01 Mar 1998) |
| visionist | A visionary. Source: Websters Dictionary (01 Mar 1998) |
| visionless | Destitute of vision; sightless. Source: Websters Dictionary (01 Mar 1998) |
| achromatic vision | A severe congenital deficiency in colour perception, often associated with nystagmus and reduced visual acuity. Synonym: achromatic vision, monochromasia, monochromasy, monochromatism. Origin: G. A-priv. + chroma, colour, + opsis, vision (05 Mar 2000) |
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| binocular vision | Vision with a single image, by both eyes simultaneously. (05 Mar 2000) |
| blue vision | A condition in which all objects appear blue; may temporarily follow cataract extraction. Synonym: blue vision, cyanopia. Origin: cyano-+ G. Opsis, vision (05 Mar 2000) |
| red vision | An abnormality of vision in which all objects appear to be tinged with red. Synonym: red vision. Origin: erythro-+ G. Ops, eye (05 Mar 2000) |
| central vision | Vision stimulated by an object imaged on the fovea centralis. Synonym: direct vision. (05 Mar 2000) |
| peripheral vision | Vision resulting from retinal stimulation beyond the macula. Synonym: indirect vision. (05 Mar 2000) |
| green vision | A condition in which objects appear to be coloured green, as may occur in digitalis intoxication. Synonym: green vision. Origin: chloro-+ G. Opsis, eyesight (05 Mar 2000) |
| rod vision | Vision when the eye is dark-adapted. See: dark adaptation, dark-adapted eye. Synonym: night vision, rod vision, scotopia, twilight vision. (05 Mar 2000) |
| chromatic vision | A condition in which objects appear to be abnormally coloured or tinged with colour; designated according to the colour seen: xanthopsia, yellow vision; erythropsia, red vision; chloropsia, green vision; cyanopsia, blue vision. Synonym: chromatic vision, coloured vision, tinted vision. Compare: dyschromatopsia. Origin: chromato-+ G. Opsis, vision (05 Mar 2000) |
| photopic vision | Vision when the eye is light-adapted. See: light adaptation, light-adapted eye. Synonym: cone vision, photopia. (05 Mar 2000) |
| coloured vision | A condition in which objects appear to be abnormally coloured or tinged with colour; designated according to the colour seen: xanthopsia, yellow vision; erythropsia, red vision; chloropsia, green vision; cyanopsia, blue vision. Synonym: chromatic vision, coloured vision, tinted vision. Compare: dyschromatopsia. Origin: chromato-+ G. Opsis, vision (05 Mar 2000) |
| colour vision defects | Mild to severe impairment in the ability to discriminate or differentiate hues. This disorder may be acquired as a result of diseases of the cones or x chromosome-linked where there is an abnormality but not a complete absence of one of the cone pigments. (12 Dec 1998) |
| cone vision | Vision when the eye is light-adapted. See: light adaptation, light-adapted eye. Synonym: cone vision, photopia. (05 Mar 2000) |
| multiple vision | polyopia |
| halo vision | A condition in which coloured or luminous rings are seen around lights. (05 Mar 2000) |