• This study of two types of optokinetic nystagmus (OKN) provides evidence that previously reported pursuit impairments in schizophrenics may be due to a cortical dysfunction. Differences in responses to partial-field and full-field OKN stimuli strongly support the hypothesis that there are two functionally distinct but anatomically overlapping mechanisms that can produce nystagmus responses. Partial-field OKN is composed of alternating phases of pursuit and saccadic movements. The slow phases of partial-field OKN, like pursuit eye movements, are of significantly poorer quality in schizophrenics compared with normal controls. Full-field OKN, however, is intact in both groups. Partial-field OKN is an improved test for pursuit abnormalities that reflect disturbances of nonvoluntary attention.
Latham C, Holzman PS, Manschreck TC, Tole J. Optokinetic Nystagmus and Pursuit Eye Movements in Schizophrenia. Arch Gen Psychiatry. 1981;38(9):997-1003. doi:10.1001/archpsyc.1981.01780340049006