Schizophrenia and Orthoptic Conditions: A Literature Review.

Purpose: A narrative review of the literature reporting ocular abnormalities in patients with schizophrenia was undertaken to determine the types and prevalence of orthoptic conditions in this patient cohort. Methods: A systematic search of multiple databases yielded 1,974 studies published between January 1992 and January 2022. All were screened for relevance based on their title and abstract. Results: Seventeen studies were included in the final review. Ocular abnormalities reported in schizophrenia included a high incidence of strabismus, reduced visual acuity and reduced stereopsis compared to controls. Additionally, eye movement abnormalities (including reduced smooth pursuit gain and increased prosaccade latency) were frequently reported. Reduced visual acuity was associated with negative symptoms and reduced quality of life in schizophrenia. Conclusions: Orthoptists and eye care professionals should be aware that a higher incidence of strabismus, reduced visual acuity, reduced stereoacuity, and eye movement abnormalities are reported in patients with schizophrenia. Further research is required to determine whether, or to what extent, ocular abnormalities and visual disturbances influence or exacerbate the symptoms of schizophrenia, and whether there is an effect of schizophrenia medication on these orthoptic conditions.