visual acuity

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Related to Twenty-twenty vision: distance acuity

acuity

 [ah-ku´ĭ-te]
1. Acuteness (see acute [def. 2]); the level of severity of an illness. This is one of the parameters considered in patient classification systems that are designed to serve as guidelines for allocation of nursing staff, to justify staffing decisions, and to aid in long-range projection of staffing and budget.
2. clearness of the visual perception of an image.
visual acuity the ability to discriminate visually between forms.
 Visual field chart illustrating the divisions of the visual field related to visual acuity. (Courtesy of Josephine C. Moore, PhD, OTR.) From Pedretti and Early, 2001.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

res·o·lu·tion a·cu·i·ty

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 a patient sees the test types (usually 6 m. or 20 ft.), and the second, the distance at which the test types subtend an angle of 5 min.; for example, vision of 6/9 indicates a test distance of 6 m. and recognition of symbols that subtend an angle of 5 min. at a distance of 9 m.
Synonym(s): visual acuity
Farlex Partner Medical Dictionary © Farlex 2012

visual acuity

n.
Sharpness of vision, especially as tested with a Snellen chart. Normal visual acuity based on the Snellen chart is 20/20.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

visual acuity

Central vision Ophthalmology The ability to distinguish details and shapes of objects; a measure of the ability to resolve distinct objects or fine details with the eye
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

vis·u·al a·cu·ity

(vizh'ū-ăl ă-kyū'i-tē)
Sharpness or clarity of vision, measured as the ability to distinguish letters or other images of various sizes at a fixed distance, usually with a Snellen chart. Normal rating by such means is 20/20 vision.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

visual acuity

The extent to which an eye is capable of resolving fine detail. Visual acuity is measured by means of a SNELLEN'S CHART TEST.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

Visual acuity

The ability to distinguish details and shapes of objects.
Mentioned in: Amblyopia, Myopia, Presbyopia
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

agnosia 

Inability to recognize the import of sensory stimuli (e.g. to recognize colour, faces, shape and the orientation of objects), although the receptors and the sensory pathway are intact. The condition is attributed to bilateral lesions in the association areas of the cortex. If the sense of sight is affected, it is called visual agnosia (perceptual or psychic blindness). See alexia; optical apraxia; prosopagnosia.

agraphia 

Inability to write, usually as a result of a brain lesion. If the person can write from dictation but not from copying, it is called visual agraphia.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann

vis·u·al a·cu·ity

(vizh'ū-ăl ă-kyū'i-tē)
Sharpness or clarity of vision, measured as the ability to distinguish letters or other images of various sizes at a fixed distance, usually with a Snellen chart. Normal rating by such means is 20/20 vision.
Medical Dictionary for the Dental Professions © Farlex 2012