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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]
Vision (unaided) VA Visual acuity VA Dcc - VA Dsc Visual acuity with Distant chart with correctors Visual acuity with eye chart at Distant 20 feet (6 m) and with (cc: Latin cum correctore) correctors (spectacles); Dsc is without (sc: Latin sine correctore) correctors. See Visual_acuity#Legal_definitions: VA Nsc - VA Ncc
Snellen chart. Purpose. Snellen chart is used to estimate visual acuity (last three rows are 20/15, 20/13 and 20/10) 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 ...
Contact lenses. to correct refractive errors of the eye; a little invasive. Phoropter. used in refraction testing. Tonometers. used to determine the intraoccular pressure (IOP) - useful in glaucoma; video link for various types of tonometers. Speculum: to keep the eyes open during any operation. Universal eye speculum.
The human eye is a sensory organ in the visual system that reacts to visible light allowing eyesight. Other functions include maintaining the circadian rhythm, and keeping balance . Arizona Eye Model. "A" is accommodation in diopters. The eye can be considered as a living optical device. It is approximately spherical in shape, with its outer ...
Eye examination for visual acuity. Visual acuity is a measure of the spatial resolution of the visual processing system. VA, as it is sometimes referred to by optical professionals, is tested by requiring the person whose vision is being tested to identify so-called optotypes – stylized letters, Landolt rings, pediatric symbols, symbols for the illiterate, standardized Cyrillic letters in ...
29271-4. An eye examination, commonly known as an eye test[ 1], is a series of tests performed to assess vision and ability to focus on and discern objects. It also includes other tests and examinations pertaining to the eyes. Eye examinations are primarily performed by an optometrist, ophthalmologist, or an orthoptist .
Snellen chart.svg. Size of this PNG preview of this SVG file: 481 × 599 pixels. Other resolutions: 192 × 240 pixels | 385 × 480 pixels | 616 × 768 pixels | 821 × 1,024 pixels | 1,643 × 2,048 pixels | 1,303 × 1,624 pixels. Original file (SVG file, nominally 1,303 × 1,624 pixels, file size: 112 KB) This is a file from the Wikimedia ...