What does "optic" mean?

Additional senses

1. 2.Of or pertaining to vision or sight. The moon, whose orb Through optic glass the Tuscan artist views. Milton.
2. 3.Of or pertaining to the eye; ocular; as, the optic nerves (the first pair of cranial nerves) which are distributed to the retina. See Illust. of Brain, and Eye.
3. 4.Relating to the science of optics; as, optical works. 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.