tunnel vision vs woolgathering

tunnel vision

noun
  • The tendency to focus one's attention on one specific idea or viewpoint, to the exclusion of everything else. 

  • A restricted field of vision as the result of looking through some type of object or a medical condition. 

woolgathering

noun
  • Indulgence in idle fancies or daydreams. 

  • The gathering of fragments of wool torn from sheep by bushes, etc. 

How often have the words tunnel vision and woolgathering occurred in a corpus of books? (source: Google Ngram Viewer )