From the Guidelines
Charles Bonnet syndrome is a condition characterized by recurrent, vivid visual hallucinations in patients with vision loss, and management should focus on reassurance, improving lighting, and social engagement, as stated in the 2023 vision rehabilitation preferred practice pattern 1. The syndrome occurs because when the brain receives less visual input due to eye diseases, it fills in the gaps with stored images. 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 2020 age-related macular degeneration preferred practice pattern, patients with severe visual loss related to age-related macular degeneration who experience Charles Bonnet syndrome should be informed that visual symptoms are not unusual and do not represent a sign of psychosis or mental deterioration 1. Management strategies for Charles Bonnet syndrome include:
- Improving lighting
- Staying socially engaged
- Using eye movements or blinking when hallucinations occur In severe cases where hallucinations cause significant distress, medications like anticonvulsants, antipsychotics, or selective serotonin reuptake inhibitors might be prescribed at low doses, though evidence for their effectiveness is limited, as discussed in the context of vision rehabilitation 1. The hallucinations often decrease in frequency over time as the brain adapts to vision loss. Patients should understand that this is a common condition affecting up to 40% of people with significant vision impairment, and discussing it openly with healthcare providers can help reduce anxiety about the experience.
From the Research
Definition and Characteristics of Charles Bonnet Syndrome
- Charles Bonnet syndrome (CBS) is characterized by recurrent or persistent complex visual hallucinations in visually impaired individuals with intact cognition and no evidence of psychiatric illness 2.
- Patients with CBS usually retain insight into the unreal nature of their hallucinations 2, 3.
- The syndrome often affects elderly patients with vision changes, such as age-related macular degeneration, glaucoma, and cataract 2, 3.
Prevalence and Risk Factors
- CBS affects 12 to 15% of visually impaired patients 3.
- The main risk factors for CBS are old age and severe visual impairment 3.
- Visual impairment appears to be a non-specific risk factor for visual hallucinations in some conditions, such as late paraphrenia and neurodegenerative diseases like Alzheimer's disease or Parkinson's disease 3.
Treatment and Management
- Reassurance and explanations are sufficient in most cases of CBS 3, 4.
- Non-pharmacological and pharmacological interventions have been reported to be useful in the treatment of CBS 2.
- Donepezil can be a favorable option in CBS patients with Alzheimer's type dementia 2.
- Anticonvulsivant drugs may help in some instances of CBS 3.
- Visual improvement and patient reassurance remain the mainstays of treatment for CBS 4.
Diagnostic Criteria and Implications for Nursing Practice
- Despite long recognition of the syndrome, diagnostic criteria for CBS are not established 5.
- There is no recognized evidence-based medical treatment for CBS 5.
- Current best practice is identifying the condition and providing reassurance and education, a role that mental health nurses aware of CBS can fulfill 5.