Charles Bonnet Syndrome in a Patient with Parkinson's Disease and Bilateral Posterior Capsule Opacification.

Charles Bonnet syndrome (CBS) is a condition of visual hallucinations or disturbances occurring in patients with visual pathway pathology not due to underlying psychiatric, metabolic, or neurologic disease. A patient with Parkinson's disease experiencing visual hallucinations was evaluated by the ophthalmology service and found to have decreased vision due to bilateral reversible posterior capsular opacification. The patient's hallucinations did not improve on clozapine, a medication requiring careful monitoring due to potentially severe systemic side effects. However, the hallucinations resolved and vision improved after bilateral treatment of the posterior capsular opacification. Clozapine was then discontinued, and the patient was able to resume his previous Parkinson's disease therapy. This case highlights the importance of considering visual pathway pathology as a contributing factor to visual hallucinations, even in patients with previously diagnosed underlying psychiatric, metabolic, or neurologic disease that could additionally be the etiology of the visual disturbances.