Search results
Results from the WOW.Com Content Network
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.
He argues for need to standardize vision tests and produces three reading charts to avoid memorization. 1854 Eduard Jäger von Jaxtthal, a Vienna oculist, makes improvements to eye chart test types that were developed by Heinrich Kuechler. He publishes, in German, French, English and other languages, a set of reading samples to document ...
Form deprivation myopia occurs when the eyesight is deprived by limited illumination and vision range, [79] or the eye is modified with artificial lenses [80] or deprived of clear form vision. [81] In lower vertebrates, this kind of myopia seems to be reversible within short periods of time.
A distant object is defined as an object located beyond 6 meters (20 feet) from the eye. [citation needed] When an object is located close to the eye, the rays of light from this object no longer approach the eye parallel to each other. Consequently, the eye must increase its refractive power to bring those rays of light together on the retina.
The 1950s also marked a time of notable development in the performance modeling of night vision imaging systems. From 1957 to 1958, Johnson, a United States Army Night Vision & Electronic Sensors Directorate (NVESD) [ 2 ] scientist, was working to develop methods of predicting target detection, orientation, recognition, and identification.
The study's results were that eye irritation was the most frequent symptom in industrial building spaces, at 81%. Modern office work with use of office equipment has raised concerns about possible adverse health effects. [91] Since the 1970s, reports have linked mucosal, skin, and general symptoms to work with self-copying paper.
Optometry is a healthcare profession that is autonomous, educated, and regulated (licensed/registered), and optometrists are the primary healthcare practitioners of the eye and visual system who provide comprehensive eye and vision care, which includes refraction and dispensing, detection/diagnosis and management of disease in the eye, and the ...
The f-number of the human eye varies from about f /8.3 in a very brightly lit place to about f /2.1 in the dark. [17] Computing the focal length requires that the light-refracting properties of the liquids in the eye be taken into account. Treating the eye as an ordinary air-filled camera and lens results in an incorrect focal length and f-number.