Rolling of the eye around its visual axis during normal ocular movements.

Abstract

DEFINITIONS In European literature rotation of the eye around its visual axis is usually calledrolling. Apparent rollingduring rotation of the normal eye around an oblique axis in Listing's plane is calledtorsion. In American literature rotation around the visual axis is usually calledtorsionand apparent rolling during rotation of the normal eye around an oblique axis in Listing's plane is calledfalse torsion.It would eliminate confusion if one or the other group would find acceptance. In this paper the following definitions will be used: Rolling—rotation of the eye around its visual axis. Torsion (or false torsion)—apparent rolling when the normal eye rotates about an oblique axis in Listing's plane. COORDINATE SYSTEMS A coordinate system is anything which is used as a reference to locate the position of a point in space. It could be the horizon, a series of horizontal or vertical lines or planes, the