a measure of spatial resolution the measure of the abiltiy to visually discriminate
The clarity or clearness of the vision, a measure of how well a person sees The ability to distinguish details and shapes of objects; also called central vision It is measured on the familiar "Snellen's chart" with its decreasing size of letters
Sharpness of vision, especially as tested with a Snellen chart. Normal visual acuity based on the Snellen chart is 20/20
Measure of eye's ability to distinguish object details and shape Assessed by smallest identifiable object that can be seen at a specified distance, usually 20 feet for distance vision and 16 inches for near vision See Free Eye Tests
the relative ability of the visual system to resolve detail, usually expressed as the reciprocal of the minimum angular separation, in minutes of arc, of two lines just resolvable as separate and that forms in the average human eye an angle of one minute of arc; often measured by a "Snellen test," a test presenting letters of graduated sizes to determine the smallest size that can be read at a standard distance (a 20/20 letter located 20 feet away from an eye subtends an angle of 5 minutes of arc at the eye); "normal" acuity in the human eye is 20/20, although some eyes are capable of 20/15 or even 20/10 acuity