| visual acuity | <microscopy> The ability to detect fine details or small distances with the eye. Visual acuity can vary substantially depending on the definition used and method of measurement chosen. Under favourable conditions, the resolution of the human eye or ability to distinguish the twoness of adjoining lines, is about I minute of arc while the threshold delectability, or the detection of misaligned steps in a line (which is also a form of visual acuity), can be as low as a fraction of a second of arc. (05 Aug 1998) |
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| absolute intensity threshold acuity | The minimal light that can be seen. (05 Mar 2000) |
| acuity | <ophthalmology> The clarity or clearness, especially of the vision or hearing. Origin: L. Acuitas = sharpness (18 Nov 1997) |
| Vernier acuity | The detection of displacement of a portion of a line. (05 Mar 2000) |
| visibility acuity | The recognition of an object on a background of different character. (05 Mar 2000) |
| resolution acuity | The detection of a target having two or more parts, often measured by using the Snellen test types; indicated by two numbers: the first represents the distance at which an individual sees the test types (usually 6 meters or 20 feet), and the second, the distance at which the test types subtend an angle of 5 minutes; e.g., vision of 6/9 indicates a test distance of 6 meters and recognition of symbols which subtend an angle of 5 minutes at a distance of 9 meters. Synonym: visual acuity. (05 Mar 2000) |
| spatial acuity | The detection of the shape of a test object; e.g., perceiving polygons of the same size but with different numbers of sides. (05 Mar 2000) |
| stereoscopic acuity | The detection of differences in distance by superimposition of slightly different retinal images into a single image to the brain. (05 Mar 2000) |
| accessory visual apparatus | The eyelids, with lashes and eyebrows, lacrimal apparatus, conjunctival sac, and extrinsic muscles of the eyeball. Synonym: organa oculi accessoria, accessory organs, accessory visual apparatus, adnexa oculi, appendages of eye. (05 Mar 2000) |
| Bender Visual Motor Gestalt test | <psychology> A psychological test used by neurologists and clinical psychologists to measure a person's ability to visually copy a set of geometric designs. It consists of nine geometric designs on cards. The subject is asked to redraw them from memory after each one is presented individually. It is useful for measuring visuospatial and visuomotor coordination to detect brain damage. Synonym: Bender Visual Motor Gestalt test. (14 Aug 2000) |
| Broca's visual plane | A plane drawn through the visual axes of each eye. (05 Mar 2000) |
| receptor, visual | The layer of rods and cones, the visual cells, of the retina. (12 Dec 1998) |
| pattern recognition, visual | Visually perceived characters, shapes, displays, or designs. (12 Dec 1998) |
| visual | Pertaining to vision or sight. Origin: L. Visualis, from videre = to see (18 Nov 1997) |
| visual agnosia | The inability to recognise objects by sight; usually caused by bilateral parieto-occipital lesions. Synonym: optic agnosia. (05 Mar 2000) |