Charles Bonnet syndrome (CBS) is a disorder in older adults, and is characterized by a triad of recurrent vivid visual hallucinations, ocular pathology causing visual impairment due to lesions in central or peripheral visual pathways, and normal cognitive status. It is often misdiagnosed as a psychosis, early dementia or a drug related condition. Hypoxemia was anecdotally reported as a cause of CBS.

We present an older adult with CBS caused by severe obstructive sleep apnea syndrome.

To report a case study, describing treatment of obstructive sleep apnea syndrome as a cause of CBS.

A case study is presented and discussed.

An older male adult was admitted to hospital for persistent vivid visual hallucinations. There was no personal or family history of mental illness. Neurological examination was normal, except for visual impairment due to age related macular degeneration. The remainder of his physical examination was normal. Previous treatment with antipsychotics proved not to be effective. Severe hypoxemia (SaO2 79%) was diagnosed with overnight pulse oximetry and subsequent polysomnography revealed an obstructive sleep apnea syndrome. After three nights of nasal continuous positive airway pressure, the vivid hallucinations ceased.

Physicians need to understand the underlying causes and mechanisms of CBS. One should be aware of the importance of a full clinical examination and sleep apnea research in elderly persons with visual impairment.

The authors have not supplied their declaration of competing interest.