Acuity test, visual: This test measures how well you see at various distances. It is the familiar eye chart test.
The eye chart itself -- the usual one is called Snellen's chart -- is imprinted with block letters that line-by-line decrease in size, corresponding to the distance at which that line of letters is normally visible.
The letters on Snellen's chart are, not surprisingly, called Snellen's test type. Each block letter is quite scientific in design (so that at the appropriate distance the letter subtends a visual angle of 5 degrees and each component part subtends an angle of 1 minute).
The chart and the letters are named for a 19th-century Dutch ophthalmologist Hermann Snellen (1834-1908) who came up with them as a test of visual acuity. Visual acuity refers to the clarity or clearness of the vision, a measure of how well a person sees. The word "acuity" comes from the Latin "acuitas" = sharpness.
The visual acuity test is used to determine the smallest letters a person can read on a standardized chart (Snellen chart) or a card held 14 - 20 feet away. How the ...
Wondering if you have a visual loss? Take the visual acuity test and find out.
Visual acuity test Definition The visual acuity testis used to determinethe smallest letters a person can read on a standardized chart or card held 14- 20 feet away.
Visual acuity test The visual acuity test is used to determine the smallest letters a person can read on a standardized chart or card held 14 - 20 feet away.
Normal vision and visual acuity and ... calibrated for different test distances, so that rooms do not have to be 20 feet long. Alternative forms of visual acuity ...