| 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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| Amsler's chart | A 10-cm square divided into 5-mm squares upon which an individual may project a defect in the central visual field. (05 Mar 2000) |
| chart | 1. A recording of clinical data relating to a patient's case. Synonym: curve. 3. In optics, symbols of graduated size for measuring visual acuity, or test types for determining far or near vision. See: Snellen's test types. Origin: L. Charta, sheet of papyrus (05 Mar 2000) |
| Walker's chart | A system of plotting the relative foetal and placental sizes. (05 Mar 2000) |
| quality control chart | A chart illustrating the allowable limits of error in laboratory test performance, the limits being a defined deviation from the mean of a control serum, most commonly ±2 SD. See: quality control. (05 Mar 2000) |
| isometric chart | A chart or graph that displays three dimensions on a plane surface. (05 Mar 2000) |
| Tanner growth chart | A series of chart's showing distribution of parameters of physical development, such as stature, growth curves, and skinfold thickness, for children by sex, age, and stages of puberty. (05 Mar 2000) |
| 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) |
| 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) |