Not sure what that is in laymans terms... But I cant read the large letter at the top of the test chart without my glasses, so that may give some idea as to how bad 20/80 may be...
IIRC, the first number relates to you, the second number relates to a 'normal population' as a comparison. So 20/80 would mean that you can see an object at 20m distance that others can see at 80m distance. So yes, milk bottles or more carrots required!