look through vs read through

look through

verb
  • To take a view of the contents of; search in, either with the eyes or by hand. 

  • To appear or pretend not to see something or someone who is clearly visible. 

  • Used other than figuratively or idiomatically: see look, through. 

read through

verb
  • To thoroughly read something to check or proofread it 

  • To read and obey a signal that is beyond the applicable one (often mistakenly) 

  • To read a script out loud casually with other actors but without blocking 

How often have the words look through and read through occurred in a corpus of books? (source: Google Ngram Viewer )