Charles Bonnet syndrome
Pronunciation: sharl bon-NAY
Complex visual hallucinations in patients with visual impairment but preserved cognitive function, not associated with psychiatric illness.
Full Definition
Charles Bonnet syndrome is a condition characterized by complex, vivid visual hallucinations that occur in patients with significant visual impairment but preserved cognitive function and absence of psychiatric illness. Named after the Swiss philosopher who first described the phenomenon in his grandfather, the syndrome is thought to result from abnormal neural activity in visual processing areas deprived of normal input due to eye disease or visual pathway damage. Hallucinations are typically elaborate and may include people, animals, buildings, or geometric patterns. Patients usually retain insight that the visions are not real, distinguishing this condition from hallucinations associated with psychiatric disorders or dementia. The syndrome commonly affects elderly patients with age-related macular degeneration, glaucoma, or other causes of severe visual loss. Recognition is important to reassure patients and families that the hallucinations do not indicate mental illness.
Usage
Usage note: Named syndrome; capitalize both names. Emphasize lack of psychiatric association when documenting.
In Context
- "The patient's complex visual hallucinations were consistent with Charles Bonnet syndrome secondary to advanced macular degeneration." — Ophthalmology consultation
- "Education about Charles Bonnet syndrome provided significant reassurance to the worried family members." — Patient counseling note