Eye movement characteristics in schizophrenia: A recent update with clinical implications

Abstract

Eye movements are indispensable for the collection of visual information in everyday life. Many findings regarding the neural basis of eye movements have been accumulated from neurophysiological and psychophysical studies. In the field of psychiatry, studies on eye movement characteristics in mental illnesses have been conducted since the early 1900s. Participants with schizophrenia are known to have characteristic eye movements during smooth pursuit, saccade control, and visual search. Recently, studies evaluating eye movement characteristics as biomarkers for schizophrenia have attracted considerable attention. In this article, we review the neurophysiological basis of eye movement control and eye movement characteristics in schizophrenia. Furthermore, we discuss the prospects for eye movements as biomarkers for mental illnesses.

Recent updates of eye movement abnormalities in patients with schizophrenia: A scoping review

“…Although it is possible to attend covertly to a spatial location, 31, 32 it is more effective to fixate the eyes on what one chooses to attend to. Therefore, the fundamental point of eye behavior reflecting one's attention (and consequently thoughts) 33–41 is attractive as a measurable indicator (biomarker) of SZ, detected through an analysis of gaze metrics 42–44 …”

“…Based on these findings, several independent research groups underlined the necessity to incorporate vision research into brain imaging studies; to investigate the relationship between eye movements, and structural and functional brain abnormalities in cognitive subgroups of SZ 225–227, 232, 233 . Furthermore, to show eye movement abnormalities among SZ patients and their relationship with patients’ social/intellectual functioning, 182, 234 researchers actively studied the association between eye movement abnormalities and (i) work hours (obtained through the Social Activity Assessment), 235 and (ii) the Wechsler Adult Intelligence Scale 44, 182, 230 . However, further research questions regarding the relevance between exploratory eye movements and everyday life functioning (e.g.…”

Impaired inhibition of return during free-viewing behaviour in patients with schizophrenia

“…Eye movement abnormalities have been proposed as a biomarker for SZs [5][6][7][8] . However, previously reported eye movement abnormalities, such as difficulty in executing voluntary saccades and poor performance in smooth pursuit, were also related to patients' drug treatment histories, raising the possibility that these abnormalities simply reflect side effects of pharmacological treatment on the oculomotor system 6,[57][58][59][60] .…”

“…Patients with schizophrenia (SZs) commonly show deficits in eye movement control that manifest as atypical visual exploration 1 – 4 . Eye movement abnormalities in SZs have been proposed as a biomarker reflecting the underlying pathophysiology of the disorder 5 – 8 . For example, difficulties exhibited by SZs in performing smooth pursuit are related to various cognitive dysfunctions in visual motion processing and predictive control 9 , while problems with antisaccade are associated with working memory and inhibitory control 10 , 11 .…”

Spontaneous eye movements during eyes-open rest reduce resting-state-network modularity by increasing visual-sensorimotor connectivity

“…From a theoretical perspective, identifying neural systems controlling eye movement during rest could allow better partitioning between relatively more 'active', (oculo)motor-related aspect of RS as opposed to other more -3-Journal: NETWORK NEUROSCIENCE / Title: Spontaneous eye-movements and resting-state connectivity Authors: Koba et al covert, non-motor-related aspects of RS. Finally, eye-movement themselves could be a possible confounder when studying healthy and clinical populations that differ in oculomotor control including autism (e.g., Takarae, Minshew, Luna, Krisky, & Sweeney, 2004), Parkinson's Disease (e.g., Pretegiani & Optican, 2017;Zhang et al, 2018) or schizophrenia (e.g., Dowiasch et al, 2016;Morita, Miura, Kasai, & Hashimoto, 2020).…”