Duction

A duction is an eye movement involving only one eye. There are generally six possible movements depending upon the eye's axis of rotation:
 * 1) Abduction refers to the outward movement of an eye.
 * 2) Adduction refers to the inward movement of an eye
 * 3) Supraduction / sursumduction / elevation
 * 4) Infraduction / deorsumduction / depression
 * 5) Incycloduction / intorsion
 * 6) Excycloduction / extorsion

Forced duction test
The forced duction test is performed in order to determine whether the absence of movement of the eye is due to a neurological disorder or a mechanical restriction.

The anesthetized conjunctiva is grasped with forceps and an attempt is made to move the eye ball in the direction where the movement is restricted. If a mechanical restriction is present, it will not be possible to induce a passive movement of the eye ball