naked-eye vs ocular

naked-eye

adj
  • Pertaining to the unaided eye, as in unaided sight. 

ocular

adj
  • Of, or relating to the eye, or the sense of sight 

  • Seen by, or seeing with, the eye; visual. 

  • Resembling the eye. 

noun
  • Any of the scales forming the margin of a reptile's eye. 

  • The eyepiece of a microscope or other optical instrument. 

How often have the words naked-eye and ocular occurred in a corpus of books? (source: Google Ngram Viewer )