Search results
Results from the WOW.Com Content Network
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 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.
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.
The simplest form of perimetry uses a white tangent screen. [3] Vision is tested by presenting different sized pins attached to a black wand, which may be moved, against a black background. [3] This test stimulus (pins) may be white or colored. [3] Goldmann perimeter
Used for neuro-ophthalmic conditions and general screening [5] as well as early detection of glaucoma [6] [7] 30-2: Measures 30 degrees temporally and nasally and tests 76 points. Used for general screening, early glaucoma and neurological conditions [6] The above tests can be performed in either SITA-Standard or SITA-Fast.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
The standard definition of normal visual acuity (20/20 or 6/6 vision) is the ability to resolve a spatial pattern separated by a visual angle of one minute of arc. The terms 20/20 and 6/6 are derived from standardized sized objects that can be seen by a "person of normal vision" at the specified distance.
Discover the latest breaking news in the U.S. and around the world — politics, weather, entertainment, lifestyle, finance, sports and much more.