Associations between psychosis and visual acuity impairment: A systematic review and meta‐analysis

Abstract

Objectives Several theories propose that visual acuity impairment is associated with psychosis. Visual impairment could lead to psychosis or the converse, or they may share underlying pathology or risk factors. In the first evidence synthesis in this area for over 25 years, we collated studies measuring the association between visual acuity impairment and psychosis. Methods We searched the MEDLINE, EMBASE, PsycINFO, and Web of Science databases for studies published from 1992 to 2020, using the Newcastle Ottawa Scale to assess risk of bias. We narratively synthesized findings and meta‐analyzed sufficiently homogenous results. Results We included 40 papers, which reported on 31 studies. Evidence from seven cohort studies was inconsistent, which precluded meta‐analysis of this study design. These contradictory results also made it difficult to draw conclusions regarding a temporal association. We found evidence for an association from eight cross‐sectional studies treating visual acuity impairment as the exposure and psychosis as the outcome [pooled odds ratio (OR) =1.76, 95% confidence interval (CI): 1.34–2.31], and four with the reverse exposure and outcome (OR: 1.85, 95% CI: 1.17–2.92). Seven case–control studies with mixed findings were found, but only two primarily addressed our research question, and these findings were mixed. Conclusions Although evidence supports a cross‐sectional association between visual acuity impairment and psychosis, further research is needed to clarify the temporal direction, given the mixed findings in cohort studies. Understanding the association may give insights into prevention strategies for people at risk of visual acuity impairment and psychosis.

When do contrast sensitivity deficits (or enhancements) depend on spatial frequency? Two ways to avoid spurious interactions

“…To consider the role of visual acuity, we also conducted analyses that matched groups on acuity (Elliot, 2016) and included this variable as a covariate. We opted to remove high-acuity controls rather than lower-acuity patients since i) poor acuity may characterize the illness (Hayes et al, 2018;Shoham et al, 2021), ii) most healthy people with poor acuity never develop psychosis; and iii) it is inappropriate to add an illness-related covariate when the groups are not matched on the covariate (Miller & Chapman, 2001). Potential issues with interpretability of visual acuity confounds are further considered in the Discussion.…”

When do contrast sensitivity deficits (or enhancements) depend on spatial frequency? Two ways to avoid spurious interactions

“…To consider the role of visual acuity, we also conducted analyses that matched groups on logMAR acuity (Elliott, 2016) and included this variable as a covariate. We opted to match groups on acuity by removing high‐acuity controls rather than lower‐acuity patients because: (i) poor acuity may characterize the illness (Hayes et al, 2019; Shoham et al, 2021); (ii) most healthy people with poor acuity never develop psychosis; and iii) it is inappropriate to add an illness‐related covariate when the groups are not matched on the covariate (Miller & Chapman, 2001). Potential issues with interpretability of visual acuity confounds are further considered in the Discussion.…”

Collaboration between Psychiatrists and Other Allied Medical Specialists for the Treatment of Delusional Disorders

“…Such findings support a significant etiological association between visual/hearing impairment and psychosis mediated by social isolation. To determine whether their findings were consistent with those of others, the same research group carried out a systematic review and meta-analysis of the topic [ 36 ]. The evidence for the association with psychosis proved strongest for visual impairment [ 37 ].…”