http://repub.eur.nl/res/aut/29093/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/23694/ 1994-03-23T00:00:00Z If one has to give a description of eye movements, what first comes to mind is the possibility of the eyes to rotate in horizontal and vertical directions. It is generally less obvious that the eyes are capable of moving in a third. namely the torsional. direction. This capability is by no means hypothetical: humans, as well as other species, possess eye muscles that are pulling in torsional direction and orbital mechanics do allow for a certain amount of torsion. Definition of torsion Torsional eye movements can be defined in two different ways, namely as a rotation about the line of sight and as a rotation about an antero-posterior (forward-to-backward) axis that is fixed in the head.