![]() ![]() If you have 20/20 visual acuity, you can read a letter from 20 feet away that the “average” human being can also read from a distance of 20 feet. Together, these numbers represent a comparison between what the “average” person should be able to see from a distance of 20 feet and what we can actually see. The large letter “E” on top on most charts corresponds to 20/200 visual acuity, and each subsequent line correlates to clearer visual acuity-20/20 being standardized as “ normal” acuity. When viewed at this distance, the bottom number of the Snellen fraction corresponds to a line of text on the eye chart. This is typically 20 feet in the United States and 6 meters in other countries throughout the world. The top number of the Snellen fraction refers to the viewing distance between the patient and the eye chart. Herman Snellen developed his system for measuring visual acuity in 1862, and it remains as the most commonly used method today. What Does 20/20 Actually Mean?Ģ0/20 and other visual acuity measurements (such as 20/40, 20/60, etc.) are known as Snellen fractions. ![]() This is why most standard eye charts show black letters or numbers on a white background, or vice versa. ![]() Visual acuity is also normally tested in high-contrast conditions. This is usually a static measurement, meaning you are standing still and the text being viewed is also stationary. When your doctor asks you to identify letters or numbers on an eye chart, they are testing your visual acuity, or the sharpness of your vision. While all of these skills are important, “20/20 vision” is really only describing one aspect of our sight-visual acuity. These include color vision, contrast sensitivity, depth perception, the ability to smoothly track moving objects, and more. Vision is a broad description of our eyesight that covers a wide range of visual skills and abilities. Even though we can reflect on past experiences through a seemingly perfect lens, is 20/20 as good as it gets when it comes to our vision? The Difference Between Visual Acuity And Our Visionīefore we explore what those magic numbers mean, it’s important to clarify what we’re measuring when we say someone has “20/20 vision.” What Does 20/20 Vision Really Mean? – Mexico NY | EyeCare Center of Mexico alarm-ringing ambulance angle2 archive arrow-down arrow-left arrow-right arrow-up at-sign baby baby2 bag binoculars book-open book2 bookmark2 bubble calendar-check calendar-empty camera2 cart chart-growth check chevron-down chevron-left chevron-right chevron-up circle-minus circle city clapboard-play clipboard-empty clipboard-text clock clock2 cloud-download cloud-windy cloud clubs cog cross crown cube youtube diamond4 diamonds drop-crossed drop2 earth ellipsis envelope-open envelope exclamation eye-dropper eye facebook file-empty fire flag2 flare foursquare gift glasses google graph hammer-wrench heart-pulse heart home instagram joystick lamp layers lifebuoy link linkedin list lock magic-wand map-marker map medal-empty menu microscope minus moon mustache-glasses paper-plane paperclip papers pen pencil pie-chart pinterest plus-circle plus power pushpin question rain reading receipt recycle reminder sad shield-check smartphone smile soccer spades speed-medium spotlights star-empty star-half star store sun-glasses sun tag telephone thumbs-down thumbs-up tree tumblr twitter user users wheelchair write yelp youtube
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