1. (extrinsic eye muscles) the muscles that move the eye within the eye socket. There are three pairs: (a) the superior rectus and inferior rectus, (b) the lateral rectus and medial rectus, and (c) the superior oblique and inferior oblique.

2. (intrinsic eye muscles) the muscles that move structures within the eye itself. They include the ciliary muscles, which alter the shape of the lens during accommodation, and the muscles of the iris, which change the size of the pupil.