Dynamic details of disparity convergence eye movements.

Classically, the primary tool for quantifying the dynamics of vergence and other eye movements has been the main sequence. The main sequence is a plot of peak velocity versus response amplitude and is particularly useful for comparing the dynamics of a large number of eye movements over a range of response amplitudes. However, the main sequence represents only the equivalent first-order behavior of a response and does not describe its dynamics in detail. Since the main sequence is based on only two points on the dynamic trajectory, it is sensitive to measurement artifacts and noise. A new methodology is presented which quantifies the equivalent second-order dynamics of eye movements using a larger region of the transient response. These new indexes were applied to vergence eye movements and were found to differentiate between subtle, but important differences in movement dynamics.