Eye movements in schizophrenia: a quantitative analysis.

A quantitative comparison of smooth pursuit eye movements of acute and chronic schizophrenics was made. Horizontal, vertical, diagonal, and pendulum tracking targets with constant or variable velocity were presented. The frequency of saccades as well as the magnitude of the spatial and temporal error during tracking was significantly greater among schizophrenics than among normals. Yet the differences between acutes and chronics were not generally significant. Performance differences were generally unaffected by the type of stimulus. The frequency of nontracked half-cycles and eye blinks was greater for chronics than for acutes or normals, and greater for acutes than normals, suggesting that sustained voluntary attention was more difficult for schizophrenics in general and chronic schizophrenics in particular. A distinctive pattern of saccade bursts was observed in the fixation and tracking records of schizophrenic subjects. These bursts were suggestive of an oculomotor deficit.