There really is no difference but you can say that by now is saying "they should be here by now" . And so far is saying "I have $10 so far".
Near sightedness or myopia is a refractive defect of the eye lens in which the image is formed in front of the retina not on it. people with this defect can see closer objects clearly while distant...
the saying is few and far between
few and far between
pi is endless! Edit: The value of Pi has so far been calculated to more than two million places.