Figure 3.

An example of how a large rightward horizontal saccade could reset the phase of acquired pendular nystagmus (APN) in a patient with multiple sclerosis. A sine wave at a similar frequency to the oscillations is shown in dashed gray for reference. Note that before the saccade, the horizontal component of APN and sine wave are about 180 degrees out of phase; after the saccade, this phase difference is greatly reduced (compare positions of vertical dashed lines). The single-position traces are offset to aid clarity of display; positive deflections indicate rightward eye rotations.