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Better Than 20/20 Vision? Visual Acuity Explained

VISUAL ACUITY: 20/20 MSION EXPLAINED 20/20 vision is shorthand for seeing 20ft away as if it was 2Oft away. Simple! How do our eyes shape up? Countries that use the metric system prefer the term 6/6. 6 meters is just shy of 20ft. 20/20 A HUMAN BEING This human has standard vision. He sees the Snellen chart from 20ft as if it were 20ft away. 20 FEET 6 METERS (19.6850394 FEET) EXPLAINING THE SNELLEN CHART 20000 20n00 The Snellen chart was 2 Cover an eye. TO Z developed by Dutch ophthalmologist 3 Read aloud the letters (optotypes) from largest to smallest. 2070 LPED 2050 Hermann Snellen in 1862. PECFD 2040 EDFCZP 2000 4 Visual acuity can be determined when the optotypes can no longer be identified. During a visual acuity test you will be asked to: 200s 2020 O Stand at 20ft from the chart. If you struggle to read the largest optotype a number of other tests can be carried out to determine how low your vision is. Moving closer to the eye chart: Counting fingers: Reducing distance until largest Assessing ability to count fingers on a single hand. optotype is visible, Hand Motion: Light Perception: 3 Ability to tell if a hand is moving in front of a person's face. Ability to perceive any light. MAN vs BEAST vs ASTRONAUT. LET'S COMPARE. Normal human sight Subject's eye sight 20/2 - 20/7 A HAWK Birds of Prey have up to 2-3 times better vision than humans, with a visual acuity somewhere between 20/2 - 20/7. This means a Hawk would see the Snellen chart from 20ft as if it were just 2-7ft away. 7 FEET 20 FEET 20/10 CHUCK YEAGER Neil Armstrong's hero and the first man to break the sound barrier - with a broken rib. Yeager was renowned for his exceptional eyesight and recounts shooting a deer from 600 yards without the aid of a sight. 10 FEET 20 FEET 20/40 DRIVING A CAR Both the U.S and U.K require a minimum visual acuity of 20/40 to drive a car legally. Drivers with a poorer unaided visual acuity are permitted to wear glasses or contact lenses to correct their vision to 20/40. 20 FEET 40 FEET 20/100 ASTRONAUTS AND PILOTS Though it is thought that astronauts and pilots need exceptional vision to fly, the requirement for both is surprisingly an acuity of 20/100 correctable to 20/2o with glasses, contact lenses, or laser eye surgery. 20 FEET 100 FEET 20/100 - 20/200 EDGAR DEGAS Almost blind in his later life due to eye disease, the French impressionist painter's poor eyesight caused a distinct shift in style, moving away from oil paints and fine detail to favour broad brushstrokes and pastels. 20 FEET 200 FEET 20/200 LEGALLY BLIND U.S. In the United States you are considered legally blind if your vision is correctable in the better eye to a visual acuity of 20/200 at best. Approximately 1.3 million Americans are legally blind. 20/400 LEGALLY BLIND IN THE U.K. In the UK you are considered legally blind if your visual acuity falls below 20/400. Libby Clegg, the Silver medal winning Paralympic sprinter, only has slight peripheral vision in her left eye, and is registered blind. She competes with a guide runner, but will often train without one. 20 FEET 200 FEET 400 FEET INFOGRAPHIC Lasik-Eyes.couk Clara Prieto SOURCES http://lowvision.preventblindness.org/eye-conditions/how-visual-acuity-is-measured http://en.wikipedia.org/wiki/Bird_vision http://www.sciencedaily.com/articles/v/visual_acuity.htm Yeager and Janos (1986). Yeager: An Autobiography. New York: Bantam. http://en.wikipedia.org/wiki/Blindness http://www.visionaware.org/info/everyday-living/recreation-and-leisure/arts-and-crafts/painting/1235 http://www.elizabethclegg.co.uk/

Better Than 20/20 Vision? Visual Acuity Explained

shared by Lasik-Eyes on Aug 14
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Although the term 20/20 vision is often heard in reference to perfect, exceptional, or even superhuman eyesight it is often misunderstood. This infographic compares hawks, astronauts, and notable ...

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Lasik-Eyes

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