Search results
Results from the WOW.Com Content Network
A reference value above which visual acuity is considered normal is called 6/6 vision, the USC equivalent of which is 20/20 vision: At 6 metres or 20 feet, a human eye with that performance is able to separate contours that are approximately 1.75 mm apart. [9]
At the low end of the range is the absolute threshold of vision for a steady light across a wide field of view, about 10 −6 cd/m 2 (0.000001 candela per square meter). [22] [23] The upper end of the range is given in terms of normal visual performance as 10 8 cd/m 2 (100,000,000 or one hundred million candelas per square meter). [24]
The standard definition of a reference range for a particular measurement is defined as the interval between which 95% of values of a reference population fall into, in such a way that 2.5% of the time a value will be less than the lower limit of this interval, and 2.5% of the time it will be larger than the upper limit of this interval, whatever the distribution of these values.
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.
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.
Two flight attendants for Delta Air Lines were pulled from an international flight after failing a breathalyzer test in Amsterdam on Friday. Randomly tested by Dutch authorities before a flight to ...
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.
The BSGT is used for patients with strabismus to test for suppression, normal retinal correspondence or abnormal retinal correspondence, [2] particularly in cases of manifest strabismus. [3] The Bagolini Striated Glasses Test is the test most likely to allow the demonstration of fusion in patients who fuse intermittently.