[as far as] conj (14c): to the extent or degree that "is safe, as far as we know"--often used in expressions like "as far as (something) goes" and "as far as (something) is concerned" to mean "with regard to (something)" "we felt pretty safe as far as the fire was concerned --Mark Twain" or in expressions like "as far as (someone) is concerned" to mean "in (someone's) opinion" "as far as I'm concerned, it's a mistake"
[2]as far as prep (1523): with regard to: concerning "neatly groomed and, as far as clothes, casual looking --N.Y. Times" "as far as being mentioned in the Ten Commandments, I think it is --Billy Graham"--chiefly in oral use