Table 1.

Previous methods for recording torsional eye movements. The first column includes references that describe each method. The second column lists the main algorithm used to calculate torsion. The last three columns specify whether the method can operate in real time and at what frame rate, whether it accounts for the geometry of the eyeball, and whether it attempts to address occlusion of the pupil by the eyelids. The lower part of the table includes methods that rely on subjective evaluation of iris images, fundus images, or afterimages. These methods typically measure only static torsion at a few time points and do not provide continuous recordings of dynamic changes in torsion. Notes: —: information not available; NA: not applicable.