Parametric sensitivity analysis of a homeomorphic model for saccadic and vergence eye movements.

A non-linear sixth order homeomorphic model, fitted with parameters based on eye movements and physiological data, was tuned so that it provided good simulations for the shapes of the magnitude, velocity and acceleration trajectories. Excellent quantitative agreement was obtained in terms of the Main Sequence diagrams for human eye movements. Parametric sensitivity analysis was done for a saccade of ten degree amplitude, a physiologically normal magnitude at which experimental data is both abundant and relatively noise free. Among the many useful results of this sensitivity analysis are that pulse width (PW) and pulse height (PH) were confirmed as the two controlling parameters for the human eye movement model. Output behavior was relatively insensitive to variations of the passive elements of the plant. This analysis also pointed out that more physiological data are needed to understand the role of the non-linear force-velocity relationship of the extraocular muscles.