Think sight loss, think Charles Bonnet syndrome

Visual hallucinations and sight loss in children and young adults: a retrospective case series of Charles Bonnet syndrome

BACKGROUND/AIMS

Charles Bonnet syndrome (CBS) is a complication of sight loss affecting all ages; yet, few childhood cases have been reported. Our aim is to raise awareness of this under-reported association occurring in children and young adults in order to prevent psychological harm in this age group.

METHODS

A retrospective case series reviewing medical notes of patients <25 years of age with sight loss and reported CBS at a single centre hospital eye service in London, United Kingdom. Search of electronic patient records identified 13 patients experiencing hallucinatory events over a 9-year period. Outcomes were patient demographics including ocular diagnosis, visual acuity at time of onset, characteristics of hallucinations, clinical management strategies and patient-reported affliction.

RESULTS

Eight patients were diagnosed with progressive inherited retinal diseases, primarily Stargardt disease (N=5). Clinical history indicated patients had significantly reduced best-corrected visual acuity (BCVA) in at least one eye at onset; median (IQR) worse eye BCVA was 1.0 (0.86-1.6) logarithm of minimum angle of resolution(LogMAR). CBS significantly affected patients' personal lives including education, diet and sleep. Clinical management was varied, mostly relating to reassurance at the point of contact.

CONCLUSION

We describe the clinical features of young patients with CBS, with management strategies and aspects of negative outcomes. High potential caseload and risk of psychological harm merit further research. Increased awareness among healthcare professionals and patient education to forewarn susceptible individuals may reduce the overall impact and improve coping with symptoms.

An overview of psychological and social factors in Charles Bonnet syndrome

Charles Bonnet syndrome (CBS) is a condition where cognitively normal individuals with sight impairment experience simple and/or complex visual hallucinations. The exact pathogenesis of CBS is unknown; however, deafferentation is often recognised as a causal mechanism. Studies have provided insight into the multifaceted impact of CBS on wellbeing. Onset of CBS may cause distress among those believing visual hallucinations are indicative of a neurological condition. Hallucinatory content is often congruent with the emotional response. For example, hallucinations of a macabre nature typically result in a fearful response. Visual hallucinations may be highly disruptive, causing everyday tasks to become challenging. Clinical management relies on forewarning and pre-emptive questioning. Yet, knowledge and awareness of CBS is typically low. In this review, we provide a summary of the social and psychological implications of CBS and explore recent developments aimed at raising awareness and improving patient management.

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

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.

Exacerbation of visual hallucinations in Charles Bonnet syndrome due to the social implications of COVID-19

Objective

Charles Bonnet syndrome (CBS) occurs secondary to sight loss, characterised by spontaneous visual hallucinations. Symptom manifestation can be influenced by social isolation. This research aims to evaluate the effect of the COVID-19 pandemic lockdown on patients with CBS.

Methods and analysis

A prospective cross-sectional survey of 45 individuals with active CBS. Open and closed ended questions were used to measure patient-reported features of hallucinatory experiences during the COVID-19 lockdown and perceived episode triggers. Analysis comprised of descriptive statistics, analysis of variance and associations, supplemented with qualitative descriptions.

Results

The survey was operational for 31 days during the COVID-19 pandemic (June–July 2020). The mean (±SD) age of respondents was 69.3 (±18) years and the majority (42.2%) had macular disease. Loneliness during the lockdown was associated with changes in the nature of visual hallucinations (p=0.04). Individuals experiencing greater loneliness were, on average, older than those with no changes to their feelings of loneliness (mean age 73.3±17 vs 60.2±19 years; p=0.03). Despite experiencing greater feelings of loneliness (67%), most individuals (60%) had not accessed support services for this reason.

Conclusions

Around half of respondents in this survey experienced exacerbation of visual hallucinations during the COVID-19 pandemic, which may partly be explained by loneliness and/or environmental triggers. We provide suggestions to promote effective patient self-management of symptoms.