6/14    What do the 20's in "20/20 eyesight" mean?  Thx.
        \_ It means they're violating Starbucks' trademark, since they have
           'Venti' copyrighted, or whatever.  If any optometrist ever drinks
           coffee, they're opening up themselves to one hell of a suit.  -John
        \_ Isn't that new technology neat? -- ilyas
                \_ tell of us the stars....
        \_ a standard vision test is given at a distance of 20 feet.  if
           your vision is "20/30", you can read at 30 feet what a normal
           20/16, you can see at 16 feet what a normal eye sees at 20
           eye would see at 20 feet.  on the other end, if your vision is
                \_ you've got that backwards. someone who sees 20/30 can
           20/16, you can see at 20 feet what a normal eye sees at16
           your vision is "20/30", you can read at 20 feet what a normal
           eye would see at 30 feet.  on the other end, if your vision is
           20/16, you can see at 20 feet what a normal eye sees at 16
           -danh
                \_ someone who sees 20/30 can
                see at 20 feet what the average person can see at 30 feet.
                fighter pilots need to see 20/15 or 20/10, so they can see
                at 20 feet what joe average can see at 10.
           \_ I see.  For near-sightedness, how does 20/xx translate to/from
              the number of "degrees" that some people use to measure near-
              sightedness?
                \_ maybe you mean diopters. there's only approximate
                relations between 20/x ratings and diopters.
                see http://www.lpf.com/source/rk/20something.html
                   \_ I don't know.  I was told that my short-sightedness is
                      simply "550", and everyone in my home country seems to
                      understand it.
                      \_ That's probably meant as -5.50
        \_ To be slightly more precise, it's based on ability to discern
           alpha letters at that distance.  Your 20/20 may not be my 20/20.
                     \_ As opposed to... beta letters?
                     \_ As opposed to chinese, for example.  the eye chart
                        uses block letters, easy to discern.  There are "20/20"
                        Lasik patients who can't drive safely at night.
                        \_ As opposed to shapes, colors, 2d objects, 3d objects,
                           moving objects, unmoving objects, get the picture?
                           \_ You missed the point. No reason to pull the
                              non-existant term "alpha letters" out of yer ass.
                                \_ It wasn't my ass.  Thanks for being
                                   concerned for my ass though.