Abnormal patterns of normal eye movements in schizophrenia.

The multilevel control of eye movements for the researcher in the schizophrenic disease process includes the saccadic trajectory, the dual mode tracking system, and schematically directed eye movements in fixation, in scanpaths, and other looking strategies, and in reading. Coordination of eye movements with head movement in gaze and sensory consequences and concomitants of eye movements round out the picture. Recent studies with precise bioengineering instrumentation have defined two abnormal patterns of eye movements--saccadic intrusions and saccadic "smooth" pursuit. Although these signs are not pathognomonic, they raise interesting questions concerning the relationship of these eye movements to the schizophrenic disease process.