| 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) |
| 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) |
| 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) |
| american speech-language-hearing association | A professional society concerned with the diagnosis, prevention, treatment, and remediation of speech, language, and hearing disorders. (12 Dec 1998) |
| rehabilitation of hearing impaired | Procedures for assisting a person with a hearing disorder to maximum comprehension in communication. (12 Dec 1998) |
| resonance theory of hearing | That the basilar membrane of the cochlea acts as a resonating structure, recording low tones from its apical turns and high tones from its basal turns. Synonym: Helmholtz theory of hearing. (05 Mar 2000) |
| Weber's test for hearing | The application of a vibrating tuning fork to one of several points in the midline of the head or face, to ascertain in which ear the sound is heard best by bone conduction, that ear being the affected one if the sound-conducting apparatus (middle ear) is at fault (positive test), but probably the normal one if the neurosensory apparatus is diseased (negative test). (05 Mar 2000) |
| conductive hearing loss | <otolaryngology> A form of deafness that results from a blockage of the ear canal or dysfunction of the ossicles or eardrum (sound collecting apparatus). In conductive hearing loss the auditory nerve is normal, but there exists a physical problem with the sound collecting apparatus. (05 Jan 1998) |
| hearing | The sensation of sound. (12 Dec 1998) |
| hearing aid | An electronic amplifying device designed to bring sound more effectively into the ear; it consists of a microphone, amplifier, and receiver. (05 Mar 2000) |