Main sequence of torsional saccadic eye movement - analysis by three-dimensional video-oculography

Background: Quantification of main sequence is required for three-dimensional recording and analysis of eye movement using video-oculography. However, the main sequence of torsional saccade has not been reported to the best of our knowledge. Aims/objectives: To obtain characteristics of torsional saccade using infra-red video-oculography, and to analyse the main sequence. Material and methods: Torsional saccades of 10 healthy subjects were extracted from torsional vestibulo-ocular reflex from voluntary head rotation. Angular velocities were plotted against amplitude of each saccade to obtain the main sequence of torsional saccade. Results: Main sequence of torsional saccade demonstrated non-linear characteristic. The adduction amplitude was significantly larger than abduction, while there was no significant difference in time constants. Conclusions and significance: Torsional saccade demonstrates non-linear characteristic, similar to main sequence of vertical and horizontal saccades.