Ocular torsion quantification with video images

Describes a technique to quantify eye rotations about the visual axis (ocular torsion). Two digitized polar transformed images of the iris are displayed on a video monitor in order to facilitate a visual comparison and manual interaction. Emphasis is placed on error analysis and the method´s simplicity when applied to static ocular torsion measurement. The implementation, applying averaging over ocular torsion determined in partitioned iris images, yields a theoretical resolution of 5´ of arc. In a control experiment with an artificial eye, the accuracy showed to be better than 14´ of arc. In practice, the measuring device was validated with the data from the literature by means of an experiment about ocular torsion in humans during tilt and hypergravity conditions (up to 3 g).