Eye chart, Snellen's — The familiar eye chart used to measure how well you see at various distances. Snellen s chart is imprinted with block letters that line by line decrease in size, corresponding to the distance at which that line of letters is normally visible. The … Medical dictionary
Snellen chart — A Snellen chart is an eye chart used by eye care professionals and others to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862.DescriptionThe traditional Snellen chart… … Wikipedia
Snellen chart — Snel·len chart snel ən n the chart used in the Snellen test with black letters of various sizes against a white background Snellen Hermann (1834 1908) Dutch ophthalmologist. Snellen was director of an eye clinic at Utrecht. In 1862 he introduced… … Medical dictionary
Snellen's chart — The familiar eye chart used to measure how well you see at various distances. Snellen s chart is imprinted with block letters that line by line decrease in size, corresponding to the distance at which that line of letters is normally visible. The … Medical dictionary
Snellen's test type — The letters on the familiar eye chart used to measure how well you see at various distances. The eye chart, known as Snellen s chart, is imprinted with block letters that line by line decrease in size, corresponding to the distance at which that… … Medical dictionary
Snellen chart — the commonest chart used for testing sharpness of distant vision (see visual acuity). It consists of rows of capital letters, called test types, the letters of each row becoming smaller down the chart. The large letter at the top is of such a… … The new mediacal dictionary
Snellen test type — block letters used in testing visual acuity, so designed that the whole letter subtends, at the appropriate distance, a visual angle usually of 5 minutes, and each component part subtends an angle of 1 minute. See also Snellen chart, under chart … Medical dictionary
Snellen chart etc. — Snel·len chart, etc. (snelґən) [Hermann Snellen, Dutch ophthalmologist, 1834–1908] see under chart, eye, sign, test, and test type … Medical dictionary
Snellen fraction — a ratio (such as 20/20 or 20/100) measuring the acuity (sharpness) of a person s eyesight for objects at a distance. The denominator (number after the slash) is the distance at which the detail of a letter on a standard test chart would… … Dictionary of units of measurement
Snellen — noun Dutch ophthalmologist who introduced the Snellen chart to study visual acuity (1834 1908) • Syn: ↑Hermann Snellen • Instance Hypernyms: ↑ophthalmologist, ↑eye doctor, ↑oculist … Useful english dictionary
