ANSWERS: 2
  • "If your visual acuity is determined to be 20/20, you see at 20 feet what a person with normal vision sees at 20 feet. If you have 20/40 vision, you see at 20 feet what a person with 20/20 vision would see at 40 feet. And, if you're one of the lucky ones (e.g., 20/15), you can see at 20 feet what others would have to move closer (15 feet) to see..." for the rest of the article check out http://www.ladarvision.com/eyes/default.asp
  • They use progressively smaller lines to determine your maximum seeing capability. Although 20/20 is average, some people can accurately determine smaller than average lines, and that's where 20/15 and 20/10 come from

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