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The See Clearly Method was an eye-exercise program that was marketed as an alternative to the use of glasses, contact lenses, and eye surgery to improve vision. Sales were halted by legal action in 2006. The method is not supported by basic science, and no research studies were conducted prior to marketing.
The Bates method is an ineffective and potentially dangerous alternative therapy aimed at improving eyesight.Eye-care physician William Horatio Bates (1860–1931) held the erroneous belief that the extraocular muscles caused changes in focus and that "mental strain" caused abnormal action of these muscles; hence he believed that relieving such "strain" would cure defective vision.
Various forms of eye exercises have been used for centuries. [9] The concept of orthoptics was introduced in the late nineteenth century for the non-surgical treatment of strabismus. This early and traditional form of vision therapy was the foundation of what is now known as orthoptics and was based on observation not research or evidence. [38]
Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception.In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficulties with normal daily tasks, including reading and walking. [6]
In the expression 6/x vision, the numerator (6) is the distance in metres between the subject and the chart and the denominator (x) the distance at which a person with 6/6 acuity would discern the same optotype. Thus, 6/12 means that a person with 6/6 vision would discern the same optotype from 12 metres away (i.e. at twice the distance).
With aging, the quality of vision worsens due to reasons independent of diseases of the aging eye. While there are many changes of significance in the non-diseased eye, the most functionally important changes seem to be a reduction in pupil size and the loss of accommodation or focusing capability ( presbyopia ).
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflected by objects in the environment.
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.