optic

1 :  eye

2 a :  any of the elements (as lenses, mirrors, or light guides) of an optical instrument or system —usually used in plural b :  an optical instrument

:  of or relating to seeing or the eye <the optic nerve>

1a:  of or relating to vision <optic phenomena>b:  dependent chiefly on vision for orientation <humans are basically optic animals>

2a:  of or relating to the eye :  ocularb:  affecting the eye or an optic structure

1:  any of the elements (as lenses, mirrors, or light guides) of an optical instrument or system—usually used in plural

2:  an optical instrument