Eye acceleration during large horizontal saccades in man.

The pattern of acceleration was recorded during horizontal saccadic eye movements using a light-weight accelerometer fixed to a scleral contact lens. Horizontal saccades of 15-20 degrees were dominated by either several pulses of acceleration, with a frequency of around 40 Hz. or a single acceleration-deceleration wave followed by lower amplitude polyphasic activity of about 80 Hz. These features are unlikely to be due to slippage or resonance in the contact lens-accelerometer system, as very similar patterns of acceleration were simultaneously recorded with an accelerometer taped over the closed eyelid of the contralateral eye. Analysis of simultaneous surface electromyogram recordings indicated that the multicomponent acceleration profiles were the product, at least in part of the rhythmic and synchronous modulation of eye muscle discharge during saccades