Cycloversion

Rotation of an eye about the visual axis is known as ocular torsion. Conjugate torsion of the two eyes is known as cycloversion.

Binocular torsion can be transformed into cyclovergence and cycloversion. Cyclovergence is the difference of the torsion of the left and right eyes; cycloversion is the mean of the left and right eye torsion.

In 1992, Enright recognized for the first time an association between vertical vergence and cycloversion. He observed that the vertical vergence producing a left hyperdeviation was associated with levocycloversion and vice versa. He calculated that the ratio between the vertical vergence and cycloversion was such that this cycloversion is likely mediated by the oblique muscles.