From the Guidelines
Charles Bonnet syndrome is a condition characterized by recurrent, vivid visual hallucinations in individuals with vision loss, and management strategies should focus on reassurance, improving lighting, and social engagement, rather than medication, as the condition is benign and not a sign of mental illness. The syndrome occurs due to the brain filling in gaps with stored images when it receives less visual input due to eye diseases like macular degeneration, glaucoma, or diabetic retinopathy 1. The key characteristics of Charles Bonnet syndrome include:
- Recurrent, vivid visual hallucinations
- Insight that what is seen is not real
- No other neurological or medical diagnosis to explain the hallucinations
- Some degree of vision loss As noted in the vision rehabilitation preferred practice pattern, patients with Charles Bonnet syndrome should be informed that their visual symptoms are not unusual and do not represent a sign of psychosis or mental deterioration 1. Management strategies may include:
- Improving lighting to reduce the occurrence of hallucinations
- Staying socially engaged to reduce stress and anxiety
- Using eye movements or blinking when hallucinations occur to help the brain adapt to vision loss In severe cases, medications like anticonvulsants, antipsychotics, or selective serotonin reuptake inhibitors might be prescribed at low doses, though evidence for their effectiveness is limited 1. However, the primary approach should be to reassure patients that the condition is benign and not a sign of mental illness, and to focus on improving their quality of life through vision rehabilitation and social support.
From the Research
Definition and Characteristics of Charles Bonnet Syndrome
- Charles Bonnet Syndrome (CBS) is a condition characterized by the presence of visual hallucinations, mainly complex, in patients with significant vision loss and without cognitive impairment 2.
- The syndrome typically occurs in older persons with vision impairment or deafferentation of the visual cortex 3.
- Patients with CBS often experience non-threatening hallucinations, which can be caused by decreased vision secondary to ocular disease, such as macular degeneration and diabetic retinopathy 4.
Epidemiology and Clinical Presentation
- The rise in CBS cases is due to an increased life expectancy and the development of age-related pathologies such as age-related macular degeneration (AMD) 2.
- Women over 80 years old constitute a significant proportion of patients with CBS, and AMD is a common underlying condition 2.
- The most prevalent hallucinations described by patients with CBS are of people and faces, in color, and in movement, with a frequency of several episodes per day 2.
Diagnosis and Treatment
- Diagnostic criteria for CBS are not established, and there is no recognized evidence-based medical treatment 5.
- Management for CBS includes treatment of the underlying ocular disease, as well as optimizing vision for the patient using appropriate low-vision devices 4.
- Current best practice is identifying the condition and providing reassurance and education, which can be fulfilled by mental health nurses who are aware of CBS 5.
Pathogenesis and Research
- The pathogenesis of CBS remains poorly understood, and much of the recent literature consists of case studies similar to the first published account of CBS 6.
- Imaging studies have provided some indication of the cortical areas implicated in the genesis of complex visual hallucinations, and the existence of similar hallucinatory syndromes in other sensory modalities suggests a common underlying mechanism 6.
- Further research is needed to understand the clinical presentation and behavior of CBS, and to improve its management 2, 6.