contact lens vs friction

contact lens

noun
  • A thin lens, made of flexible or rigid plastic, that is placed directly on to the eye to correct vision, used as an alternative to spectacles, or, if coloured, to change one's eye color cosmetically. 

friction

noun
  • The rubbing of one object or surface against another. 

  • A force that resists the relative motion or tendency to such motion of two bodies in contact. 

  • (Second Sino-Japanese War) Conflict, as between the Communists and non-Hanjian Kuomintang forces. 

  • Conflict, as between persons having dissimilar ideas or interests; clash. 

How often have the words contact lens and friction occurred in a corpus of books? (source: Google Ngram Viewer )