From the Guidelines
Charles Bonnet Syndrome (CBS) is a condition where people with vision loss experience visual hallucinations while remaining mentally sound, characterized by recurrent, vivid visual hallucinations, insight that what is seen is not real, no other neurological or medical diagnosis to explain the hallucinations, and some degree of vision loss. These hallucinations typically involve seeing patterns, faces, people, or scenes that aren't actually present. The syndrome occurs because when the brain receives less visual input due to eye diseases like macular degeneration, glaucoma, or diabetic retinopathy, it fills in the gaps with stored images 1.
Key Characteristics of CBS
- 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 No specific medication directly treats Charles Bonnet syndrome, but reassurance that the condition is not a sign of mental illness is crucial for management, as education and support for patients with CBS can be therapeutic 1. Patients should understand these hallucinations are a natural response to vision loss.
Management and Coping Strategies
- Reassurance and education about the condition
- Coping strategies include changing lighting conditions, blinking, moving the eyes, or engaging in social activities when hallucinations occur
- Techniques such as eye movements, changing lighting, or distraction may reduce hallucinations in some patients 1 If hallucinations cause significant distress, medications like anticonvulsants, antipsychotics, or selective serotonin reuptake inhibitors might be considered, though evidence for their effectiveness is limited 1. The syndrome often improves over time as the brain adapts to vision loss, with many patients experiencing fewer hallucinations within 12-18 months of onset. Atypical features that should raise suspicion of a diagnosis other than CBS include lack of insight into the unreal nature of the images, images that interact with the patient, or other associated neurological signs or symptoms 1.
From the Research
Definition and Characteristics of Charles Bonnet Syndrome (CBS)
- 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, 3, 4, 5.
- Patients with CBS usually retain insight into the unreal nature of their hallucinations 2, 3, 4.
- The hallucinations are often vivid, complex, and well-defined, and may be pleasant but can also cause distress 2, 3, 4, 6.
Association with Visual Impairment
- CBS is often associated with acquired visual loss, particularly age-related macular degeneration, glaucoma, and cataract 2, 3, 4, 6.
- The syndrome can occur in individuals with visual impairment due to pathologies anywhere along the visual pathway 4.
- The prevalence of CBS has been reported to be between 10% and 40% in individuals with visual impairment, with a recent study finding a prevalence of 17.5% 6.
Diagnosis and Treatment
- CBS is a diagnosis of exclusion, and careful assessment must be made to rule out other etiologies causing the symptoms 4.
- Treatment options include nonpharmacological and pharmacological interventions, with the goal of alleviating distress and improving symptoms 2, 3.
- Optimizing visual function through optical means, such as visual aids and surgical procedures, can also have beneficial effects on the hallucinations 4.