The Collaborative International Dictionary of English v.0.48:

Optic \Op"tic\ ([o^]p"t[i^]k), Optical \Op"tic*al\
   ([o^]p"t[i^]*kal), a. [F. optique, Gr. 'optiko`s; akin to
   'o`psis sight, 'o`pwpa I have seen, 'o`psomai I shall see,
   and to 'o`sse the two eyes, 'o`ps face, L. oculus eye. See
   Ocular, Eye, and cf. Canopy, Ophthalmia.]
   1. Of, pertaining to, or using vision or sight; as, optical
      illusions. [WordNet sense 2]

   Syn: ocular, optic, visual.
        [1913 Webster + WordNet 1.5]

              The moon, whose orb
              Through optic glass the Tuscan artist views.
                                                  --Milton.
        [1913 Webster]

   2. Of or pertaining to the eye; ocular; as, the optic nerves
      (the first pair of cranial nerves) which are distributed
      to the retina; the optic (or optical) axis of the eye. See
      Illust. of Brain, and Eye. [WordNet sense 3]
      [1913 Webster]

   3. Relating to the science of optics or to devices designed
      to assist vision; as, optical works; optical equipment.
      [WordNet sense 1]
      [1913 Webster +PJC]

   Optic angle (Opt.), the angle included between the optic
      axes of the two eyes when directed to the same point; --
      sometimes called binocular parallax.

   Optic axis. (Opt.)
      (a) A line drawn through the center of the eye
          perpendicular to its anterior and posterior surfaces.
          In a normal eye it is in the direction of the optic
          axis that objects are most distinctly seen.
      (b) The line in a doubly refracting crystal, in the
          direction of which no double refraction occurs. A
          uniaxial crystal has one such line, a biaxial crystal
          has two.

   Optical circle (Opt.), a graduated circle used for the
      measurement of angles in optical experiments.

   Optical square, a surveyor's instrument with reflectors for
      laying off right angles.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Optic \Op"tic\ ([o^]p"t[i^]k), n. [From Optic, a.]
   1. The organ of sight; an eye.
      [1913 Webster]

            The difference is as great between
            The optics seeing, as the object seen. --Pope.
      [1913 Webster]

   2. An eyeglass. [Obs.] --Herbert.
      [1913 Webster] Optic

WordNet (r) 3.0 (2006):

optic
    adj 1: of or relating to or resembling the eye; "ocular
           muscles"; "an ocular organ"; "ocular diseases"; "the
           optic (or optical) axis of the eye"; "an ocular spot is a
           pigmented organ or part believed to be sensitive to
           light" [syn: ocular, optic, optical, opthalmic]
    2: relating to or using sight; "ocular inspection"; "an optical
       illusion"; "visual powers"; "visual navigation" [syn:
       ocular, optic, optical, visual]
    n 1: the organ of sight [syn: eye, oculus, optic]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "optic":
   baby blues, banjo eyes, bright eyes, clear eyes, cornea, eye,
   eyeball, eyelid, goggle eyes, iris, lens, lid, naked eye,
   nictitating membrane, ocular, oculus, ophthalmic, ophthalmologic,
   optic nerve, optical, optometrical, orb, organ of vision, peeper,
   popeyes, pupil, retina, saucer eyes, sclera, seeing, starry orbs,
   unaided eye, visible, visional, visual, visual organ