Crossword clues for the word: OPTO The word OPTO has appeared as an answer to at least 9 crossword clues on different crossword puzzles. Crossword clues for OPTO Showing 1 to 9 of 9 results Clue(s) "The eye ""metry""" Eye-related prefix Eye: Prefix Intro to metry Prefix with -metry Sight opening Vision: Comb. form. Vision: Pref. Vision: Prefix