a historically near-sighted person is someone who can only remember recent history, wether it be in the recent few centuries or even just the recent few years.
July 4, John: do you realize that a year ago today we had to use bread slices instead of buns for hot dogs?
Bob: do you also that realize today is when america became independent? John: REALLY? Bob: yes, its taught in history class. John: oh, sorry, i didn't know that becuase im historically near-sighted.