Search results
Results from the WOW.Com Content Network
Near visual acuity or near vision is a measure of how clearly a person can see nearby small objects or letters.Visual acuity in general usually refers clarity of distance vision, and is measured using eye charts like Snellen chart, LogMAR chart etc. Near vision is usually measured and recorded using a printed hand-held card containing different sized paragraphs, words, letters or symbols.
A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862 as a measurement tool for the acuity formula developed by his professor Franciscus Cornelius Donders .
An example of the Landolt C eye chart (also known as the Japanese eye chart.). Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision, while the ETDRS chart is designed for use at 4 meters. [16]
Sloan letters, designed by Louise Sloan in 1959, are a set of optotypes used to test visual acuity generally used in Snellen charts and logMAR charts. This set of optotypes consists of ten specially formed "letters", C, D, H, K, N, O, R, S, V and Z. [ 1 ] These letters, unlike the ones used in older Snellen charts, are designed to give acuity ...
A good procedure is a chart, analogous to the familiar Snellen visual acuity chart, in which one letter in each row differs in depth (front or behind) sequentially increasing in difficulty. For children the fly test is ideal: the image of a fly is transilluminated by polarized light; wearing polarizing glasses the wing appears at a different ...
The value D, indicated to the left of each row, gives the distance in meters from which a person with a visual acuity of 1.0 can read the corresponding row. The value V, indicated to the right, gives the minimum visual acuity needed to read the row from a distance of 5 meters. The first row contains symbols 70 mm in size (V = 0.1); the second ...
Enjoy a classic game of Hearts and watch out for the Queen of Spades!
The "LEA Numbers Test" was the second of the LEA tests that was developed and can be used to test the visual acuity of older children and even adults. This test has a layout similar to a typical Snellen chart, with lines of numbers decreasing in size towards the bottom of the page. Like the optotypes of the LEA Symbols Test, these numbers are ...