| visibility acuity | The recognition of an object on a background of different character. (05 Mar 2000) |
|---|---|
| visibility, limit of | <microscopy> For the normal eye, the limit of visibility is considerably below the limits of resolution. It depends largely on contrast and intensity of illumination. (05 Aug 1998) |
| visible | 1. Perceivable by the eye; capable of being seen; perceptible; in view; as, a visible star; the least spot is visible on white paper. "Maker of heaven and earth, and of all things visible and invisible." (Bk. Of Com. Prayer) "Virtue made visible in outward grace." (Young) 2. Noticeable; apparent; open; conspicuous. "The factions at court were greater, or more visible, than before." (Clarendon) Visible church, the apparent church of Christ on earth; the whole body of professed believers in Christ, as contradistinguished from the invisible, or real, church, consisting of sanctified persons. Visible horizon. Same as Apparent horizon, under Apparent. Vis"ibleness, Vis"ibly. Origin: L. Visibilis, fr. Videre, visum, to see: cf. F. Visible. See Vision. Source: Websters Dictionary (01 Mar 1998) |
| visible light | <physics> Electromagnetic radiation with wavelengths between 400 nanometres and 750 nanometres. Electromagnetic radiation within this range can be detected by the human eye. Colours depend on the wavelength lengths, a short wavelength (the 400 nm side) looks blue and a long wavelength (the 750 nm side) looks red. (09 Oct 1997) |
| visible spectrum | That part of electromagnetic radiation that is visible to the human eye; it extends from extreme red, 7606 A |
| visile | 1. An obsolete term denoting the type of mental imagery in which one recalls most readily that which has been seen. Compare: audile, motile. 2. A person with such mental imagery. Synonym: visual. (05 Mar 2000) |
| visinin | <protein> Calcium binding protein containing 3 EF hand motifs. No longer thought to be activator of photoreceptor guanylate cyclase. Related to visinin, P26, 23 kD protein, s modulin, also to 21 kD CaBP and neurocalcin. (18 Nov 1997) |
| 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) |
| 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) |