Eye movement abnormalities in autism spectrum disorder and prodromal psychosis: a review of overlaps and biomarkers

Objectives Differentiating prodromal psychosis from autism spectrum disorder (ASD) during adolescence remains a major clinical challenge due to overlapping behavioral and cognitive features and the absence of reliable biological markers. This review synthesizes evidence on eye tracking and oculomotor abnormalities to evaluate their potential utility as objective biomarkers for distinguishing ASD, clinical high-risk (CHR) states, and prodromal psychosis in adolescent populations. Methods A narrative review with structured systematic elements was conducted following PRISMA 2020 reporting principles. Searches were performed in PubMed and PsycINFO, supplemented by citation tracking. Eligible studies included peer-reviewed empirical investigations using eye tracking paradigms in adolescents with ASD, CHR/ prodromal psychosis, or schizophrenia-spectrum conditions. Findings were synthesized narratively due to methodological heterogeneity. Results Forty-seven studies were included in the final narrative synthesis. Across paradigms, individuals with ASD demonstrated reduced saccade accuracy, increased endpoint variability, and atypical gaze allocation, often reflecting cerebellar and brainstem dysfunction. CHR and prodromal psychosis samples showed elevated antisaccade error rates, intrusive saccades during smooth pursuit, reduced pursuit gain, and increased fixed entropy, consistent with fronto-striatal and cortico-cerebellar dysregulation. While some oculomotor abnormalities overlapped across groups, schizophrenia-spectrum and CHR samples generally exhibited greater impairment severity and task-related disorganization than ASD alone. However, specificity was limited, and similar abnormalities were observed across other neuropsychiatric conditions. Conclusion Eye tracking metrics capture neurodevelopmentally relevant abnormalities in visual attention and oculomotor control that may complement existing clinical assessments of psychosis risk in adolescents with ASD. Current evidence supports their value as research and monitoring tools rather than standalone diagnostic markers. Longitudinal, developmentally stratified studies are required to establish predictive validity, disorder specificity, and clinical translation.