20/30 means that 20 feet from the eye chart
, your vision
is as good as a normal person's standing 30 feet from the chart! a good rule of thumb is to use your vision measurement as a percentage of normal vision.
So 20/30 would be 66%, 20/40 equal to 50%, 20/20 equal 100%, etc! so your vision is less than perfect! good idea to have it checked out!