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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]
A 1951 USAF resolution test chart is a microscopic optical resolution test device originally defined by the U.S. Air Force MIL-STD-150A standard of 1951. The design provides numerous small target shapes exhibiting a stepped assortment of precise spatial frequency specimens.
lens function compatibility Bayonet > K, M A F, FA, D-FA FA Powerzoom FA-J DA, DA-L DA-SDM, DA-DCM (KAF3) DA, D-FA (KAF4) Main changes: Camera First K-mount version A-position, electrical contacts Screw drive, with contacts for serial communication Two contacts for Powerzoom Aperture ring abandoned Small image circle In lens autofocus motor
-do-; standard chart of alphabets; video link •Colour vision: to test colour vision ••Ishihara's chart: to determine the type of colour blindness Stenopaeic slit: detection of axis of the cylindrical (astigmatism) power of the eye; glaucoma testing Implants - •Intraocular lens: prosthetic lenses implanted after lens (anatomy) removal ...
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A person taking the test covers one eye from 6 metres or 20 feet away, and reads aloud the letters of each row, beginning at the top. The smallest row that can be read accurately indicates the visual acuity in that specific eye. The symbols on an acuity chart are formally known as "optotypes". Variation of Snellen chart with another letter ...
Used with early monochrome TV systems, this chart was useful in measuring image resolution, determined by inspection of the image as displayed on a CRT. On such systems an important measure is the limiting horizontal resolution, affected by hardware and transmission quality (vertical resolution is fixed and determined by the video standard used ...
Landolt C optotypes in various sizes and orientations Landolt C optotype dimensions Golovin–Sivtsev table. The Landolt C, also known as a Landolt ring, Landolt broken ring, or Japanese vision test, is an optotype: a standardized symbol used for testing vision.