That eye movements might possess intrinsic motor rhythmicity is a possibility which to our knowledge has not hitherto been suggested.
In his report of 1903, Raymond Dodge pointed out that eye movements in response to a slowly moving visual stimulus may be interrupted by minute saccadic movements.1 This phenomenon is readily demonstrated by oculography. Contemporary investigators2 interpret such saccadic movements as positional corrections of the tracking error. Moreover, they construe the characteristic interval of 180 msec, which separates saccadic movements one from another in terms of mathematical information theory, as a sampling interval in which the central nervous system collects data which determine the magnitude of the subsequent corrective saccade.3 However, saccadic movements usually occur when the eye is tracking nothing at all, and the interval between successive saccadic movements has its characteristic period even when there is no tracking error to be corrected. Therefore, it seems
MEYER EJ. Rhythmicity of Saccadic Eye Movements. Arch Ophthalmol. 1966;76(4):554-556. doi:10.1001/archopht.1966.03850010556013