field glasses vs spectacles

field glasses

noun
  • binoculars. 

spectacles

noun
  • A pair of lenses set in a frame worn on the nose and ears in order to correct deficiencies in eyesight or to ornament the face. 

  • Synonym of pair (“score of zero runs in both innings”) 

How often have the words field glasses and spectacles occurred in a corpus of books? (source: Google Ngram Viewer )