1. Of, or relating to sight; visual
    Strabismus is an optical defect.
  2. Designed to assist or enhance sight
    A microscope is an optical instrument.
  3. Of, or relating to optics
    Refraction is an optical effect.
  4. Of, or relating to visible light
    Optical telescopes don't work when it is cloudy.
  5. Incorporating light-sensitive devices
    An optical switch opens the door automatically.

The above text is a snippet from Wiktionary: optical
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