Pinhole glasses

Pinhole glasses, also known as stenopeic glasses, are eyeglasses with a series of pinhole-sized perforations filling an opaque sheet of plastic in place of each lens. Similar to the workings of a pinhole camera, each perforation allows only a very narrow beam of light to enter the eye which reduces the size of the circle of confusion on the retina and increases depth of field. In eyes with refractive error, the result is often a clearer image. Unlike conventional prescription glasses, pinhole glasses produce a clear image without the pincushion effect around the edges (which makes straight lines appear curved). While pinhole glasses are useful for people who are both near- and far-sighted, they are not recommended for people with over 6 diopters of myopia. It should also be noted that pinhole glasses reduce brightness and peripheral vision,cite web | url=http://www.quackwatch.org/01QuackeryRelatedTopics/eyequack.html | author=Russell S. Worrall OD, Jacob Nevyas PhD, Stephen Barrett MD | title=Eye-Related Quackery | date=September 12, 2007 | accessdate=2008-03-27 | publisher=Quackwatch] and thus should not be used for driving or when operating machinery. [cite news | url=http://findarticles.com/p/articles/mi_qn4158/is_19970729/ai_n14130207 | author = Cherrill Hicks | date = July 29, 1997
location = London | publisher = The Independent | title=The truth about pinhole glasses]

Pinhole glasses have been marketed by various companies on the claim that - combined with certain eye exercises - they could permanently improve eyesight. These claims have been analyzed, but no scientific evidence has been found to support them, and they are no longer allowed to be made in the United States under the terms of a legal settlement with the Federal Trade Commission. [ [http://www.casewatch.org/ftc/news/1993/natural-vision.shtml Casewatch] ]

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