In vision science, cyclodisparity is the difference in the rotation angle of an object or scene viewed by the left and right eyes.
Furthermore, up to about 8 degrees can usually be compensated by purely sensory means, that is, without physical eye rotation.
This means that the normal human observer can achieve binocular image fusion in presence of cyclodisparity of up to approximately 16 degrees.
A proposed explanation for this phenomenon is that the motor system is coordinated in such a way that the eyes perform a torsional movement to reduce the size of the search zones and thus the computational load required for solving the correspondence problem.
For instance, camera torsion can be used to make improved use of the search range over which matching detectors or stereo matching algorithms operate, or to make a 3D slanted surface appear frontoparallel for further stereo processing.