visual acuity


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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.

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

visual acuity

n.
Sharpness of vision, especially as tested with a Snellen chart. Normal visual acuity based on the Snellen chart is 20/20.

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

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.

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.

Visual acuity

The ability to distinguish details and shapes of objects.
Mentioned in: Amblyopia, Myopia, Presbyopia

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.

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.
References in periodicals archive ?
Another study found that uncorrected refractive error accounted for nearly 73% of the cases of impaired visual acuity among Mexican Americans aged [greater than or equal to] 40 years (5), and similar findings were reported among residents in the United Kingdom (7) and Australia (10).
(35) People with subnormal visual acuity can achieve the best visual acuity with an illumination level of 500-1,000Lux.
A critical flicker frequency tester (Model: 12023A) manufactured by Lafayette Instrument Company and a vision tester (OPTEC 2000) manufactured by Stereo Optical were used to measure the CFF and visual acuity, respectively.
The purpose of this study was to determine if low-dose radiation therapy would stabilize visual acuity loss in patients with wet-type ARMD.
During the follow-up of our patients, the vision improved and the best corrected visual acuity (BCVA) at the end of three months was 80 EDTRS letters (corresponding to a vision of 20/50 on Snellen chart ).
Mean preoperative visual acuity in our study was 1.016 +-0.17 log MAR.
Visual acuity after cataract surgery in patients with age-related macular degeneration.
Differences in discrimination functions relating to visual acuity were tested using Single Factor Analysis of Variance (ANOVA).
'How then does one know that he has glaucoma early enough to prevent blindness?' There are three functions of the eye - the ability to see objects clearly which is called Visual Acuity; then the actual area which you can see in front of you - your scope of vision.
At her 1-month follow-up, the visual acuity of the right eye improved from 20/70 to 20/40, with resolution of subretinal hemorrhage and near resolution of CME.
Patient demographics, initial best-corrected visual acuity (BCVA), axial length, refractive error, color fundus photography, FFA imaging, and a history of follow-up were recorded from patient medical records.
Pre-treatment best-corrected visual acuity was 20/800 OD and 20/4000 with severe visual field loss.