What does it mean when someone has 20/20 vision?

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  • American Optometric Association. "Visual Acuity: What is 20/20 Vision?" http://www.aoa.org/x4695.xml 
  • National Institutes of Health, Medline Plus Medical Encyclopedia. "Visual Acuity Test. http://www.nlm.nih.gov/medlineplus/ency/article/003396.htm
  • NDT Research Center. "Visual Acuity of the Human Eye." http://www.ndt-ed.org/EducationResources/CommunityCollege/PenetrantTest/Introduction/visualacuity.htm
  • Strouse Watt, Wendy. "How Visual Acuity is Measured." Macular Degeneration Support. http://www.mdsupport.org/library/acuity.html