Ask a Health Professional Each week health professionals give their educated opinions on related health care topicstions. We believe that knowledge is power Andrew Congdon O.D Doctor of Optometry oto INSIGHT VISION CENTER (715) 732-2101 3003 Cleveland Avenue Marinette, WI Question: What does 20/20 mean? .horn a topnic wat..ch Contrary to popular belief, feet behind you and see that same sized letter 300 e having 20ho vision doesnt feet are in a football field. If you are correctable mean you have perfect vision. to anything better than 20/2o0, then you are not 2020 is the mathematical legally blindYou cannot be legally blind ifyou take average that every human should be able to see your glasses off,because the definition is seeing If you have 2o/zo vision, that means that your day worse than 20/200 with corection. to day tasks should be visually easy to accomplish. But what does 2o/ho mean exacthy? On the flip side you can have better than 20/o vision tool You may have z0h5 vision, which means Breaking down the numbers will explain exactly that you would stand zo feet away from a letter what 20/ho means. The numerator, or first number, and other people would have to move up to 1s feet is the number of feet you would be a letter that is a particular size The denominator, far as zh or second number, is where the average person would have to stand to see the same sined letter standing from to see that same letter Most eye charts will go as In other countries, they do not use 20lho as a measurement, since it is in feet. Rather, they use If you are 2o/3o, that means when you stand at 20 feet away from a letter, the average person could the metric system in meters stand right next to you and see that same letter If 6'6 meters The 20/2o letter E should be 's inches you are 2olio, that would mean that if you stood at large if the screen is zo feet away Some eye exam 2o feet, the average person could stand at 4o feet rooms are shorter than 2o feet so the leters are and read that same letter. 2ouo is what is required actually smaller than 1s inches. Another way to bythe govenment to be able to drive a carwithout make an exam room bigger is to use mirrors to glasses Most eye surgeries will not be done on your artificially make the ketters look 2o feet away eyes if you are better than aoiso if you want your 20/2o is the average that the normal person insurance to pay for it The definition of legally blind is 2o/ao in the better seeing eye with correction If you were legally blind, you would have to stand at 20 feet to see a letter, and the average person could stand 200 should be able to see. For this reason, most pairs of glasses are made so that you can see the 2o/20 line Generally, you are likely able to see the 2ohs line (one line better) with both eyes open if each eye is 20/zo individually