Individuals with schizophrenia have shown a relationship between hours at work and a higher eye movement score, according to a study published in Schizophrenia Research. This eye movement score consists of the gain in horizontal position, the length of the individual’s scanpath, and the length of fixations.
Eyelink 1000 was utilized to gather data on eye movement, with an integrated eye movement score consisting of horizontal position gain, length of scanpath, and duration of fixations. These metrics have shown previous success in identifying individuals with schizophrenia among others, and the score was used to measure the overall eye movement pathology in individuals with schizophrenia. The Social Activity Assessment, which was derived from the relevant section of the Modified Social Adjustment Scale, was used to record total hours at work per week.
This study included 69 individuals diagnosed with schizophrenia as well as 246 healthy controls. Individuals with schizophrenia showed a significant, positive association between work hours and eye movement score (Pearson’s correlation coefficient [R]=0.29; P =.0145). Eye movement and work hours did not show a significant correlation among healthy controls (R=-0.09; P =.162). Researchers used a hierarchical multiple linear regression analysis to test for an interaction between the diagnosis of schizophrenia and eye movement scoring on work hours, which produced a significant interaction effect (R=6.0; 95% CI, 1.5-10.5; P =.00944).
Investigators replicated this study in 118 patients with schizophrenia and 280 healthy controls in 4 other institutions. In the replication study, investigators observed a significant positive correlation between eye movement score and work hours in patients with schizophrenia (R=0.19; P = .0347; excluding patients with schizophrenia with zero work hours: R=0.27; P =.0147).
Researchers concluded that, “[our] results revealed an association between eye movement and work hours with a potential mediation of cognitive ability related to the perceptual organization in schizophrenia. This association is unsurprising in the context of previous literature because eye movement abnormalities have been shown to be associated with neurocognitive measures requiring visual processing.”
Morita K, Miura K, Fujimoto M, et al. Abnormalities of eye movement are associated with work hours in schizophrenia [published online July 12, 2018]. Schizophrenia Research. doi: 10.1016/j.schres.2018.06.064