Analysis of saccadic eye movements using an infrared video system in human subjects

Horizontal and vertical saccades were recorded and quantitatively analyzed with an infrared video recording system in 6 normal human subjects. Peak and mean saccade velocities increased exponentially as the amplitude increased. Peak velocity of horizontal saccade was significantly larger than that of vertical saccade (p less than 0.05, ANOVA test). On the other hand, duration and latency showed a linear relationship with saccade amplitude. Latency was constant (i.e. 0.21 s) irrespective of saccade amplitude in the regular eye tracking mode; however, latency slightly increased as the amplitude became larger in the randomized eye tracking mode. As a result, a slight positive correlation could be found between saccade amplitude and latency: r = 0.50 and 0.35 in horizontal and vertical saccades, respectively.