also eyepiece, "the lens or combination of lenses to which the eye is applied in an optical instrument," 1738, from eye (n.) + piece (n.1).

also eyeshade, "a shade for the eyes," 1808 as a type of headgear, from eye (n.) + shade (n.).

also eyewitness, "one who testifies to something he has seen," 1530s, from eye (n.) + witness (n.). As a verb from 1844. Related: Eyewitnessed; eyewitnessing.

also eye-ball, "the ball or globe of the eye," so called for its shape, 1580s, from eye (n.) + ball (n.1), which is attested from c. 1400 in the sense "spherical structure of the eye." As a verb, 1901, American English slang. Related: Eyeballed; eyeballing.