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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 ]
AC 2/4: Grade 2 anterior chamber angle: AC 1/4: Grade 1 anterior chamber angle: AC 0/4: Grade 0 anterior chamber angle: closed angle between cornea and iris AC/A: Accommodative convergence / Accommodation ratio the portion of the range of convergence that occurs in response to accommodation: Acc: Accommodation
Wratten numbers are a labeling system for optical filters, usually for photographic use comprising a number sometimes followed by a letter. The number denotes the color of the filter and its spectral characteristics, and these numbers can be grouped into broad categories, but the numbering system is arbitrary within a group and does not encode ...
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After the patient's distance correction is established, the patient is instructed to view small letters on a card 40 cm from the eyes. The examiner adds convex lenses in +0.25 increments until the patient first reports that they become blurry. [2] The total value of the lenses added to reach this point is the NRA value.
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]
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 ...
A numeric character reference refers to a character by its Universal Character Set/Unicode code point, and a character entity reference refers to a character by a predefined name. A numeric character reference uses the format &#nnnn; or &#xhhhh; where nnnn is the code point in decimal form, and hhhh is the code point in hexadecimal form.