• Using precise infrared recording instrumentation, we measured the eye-movement patterns in six schizophrenic patients who were taking medication and found saccadic intrusions and saccadic smooth-pursuit tracking in three. This defined some of the eye-movement irregularities reported previously by many investigators. A variety of eye-movement functions in addition to smooth pursuit exhibited these abnormalities, including fixation, vergence, and head-eye pursuit. Saccadic intrusions or saccadic pursuit also occurs in a number of neuro-ophthalmologic disorders, and occasionally In healthy normal subjects. Thus, these eye-movement abnormalities do not occur exclusively in schizophrenia.
Levin S, Jones A, Stark L, Merrin EL, Holzman PS. Identification of Abnormal Patterns in Eye Movements of Schizophrenic Patients. Arch Gen Psychiatry. 1982;39(10):1125–1130. doi:10.1001/archpsyc.1982.04290100005002