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In the most familiar acuity test, a Snellen chart is placed at a standard distance: 6 metres. At this distance, the symbols on the line representing "normal" acuity subtend an angle of five minutes of arc, and the thickness of the lines and of the spaces between the lines subtends one minute of arc. This line, designated 6/6 (or 20/20), is the ...
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.
Conversion of units is the conversion of the unit of measurement in which a quantity is expressed, typically through a multiplicative conversion factor that changes the unit without changing the quantity. This is also often loosely taken to include replacement of a quantity with a corresponding quantity that describes the same physical property ...
The Brannock Device is a measuring instrument invented by Charles F. Brannock for measuring a person's shoe size. Brannock spent two years developing a simple means of measuring the length, width, and arch length of the human foot. He eventually improved on the wooden RITZ Stick, the industry standard of the day, [2] patenting his first ...
The chart was designed by Ian Bailey [5] and Jan E. Lovie-Kitchin at the National Vision Research Institute of Australia. [1] [3] They described their motivation for designing the LogMAR chart as follows: "We have designed a series of near vision charts in which the typeface, size progression, size range, number of words per row and spacings were chosen in an endeavour to achieve a ...
The International System of Units, internationally known by the abbreviation SI (from French Système international d'unités), is the modern form of the metric system and the world's most widely used system of measurement. Coordinated by the International Bureau of Weights and Measures (abbreviated BIPM from French: Bureau international des ...
Download as PDF; Printable version; In other projects ... (3.9 in) centimetre: cm cm ... To convert from feet and inches use ...
The template is intended for conversion of heights specified in either metres or in feet and inches. Template parameters [Edit template data] Parameter Description Type Status Metres m metre metres meter meters The height in metres. Do not use if feet and inches are specified. Number optional Centimetres cm centimetre centimetres centimeter centimeters The height in centimetres. Do not use if ...