Abstract
Occurrence of visual hallucinations in patients without disturbances of consciousness is a source of serious diagnostic difficulties. The Charles Bonnet syndrome, described mostly in the elderly with vision defects, is a specific form of visual hallucinosis. Diagnostic problems with this syndrome due to its unknown etiology and the lack of commonly accepted diagnostic criteria, were discussed and exemplified by a case in which the Charles Bonnet syndrome preceded delirium by many weeks in the course of a generalized neoplastic disease. Antiepileptic drugs, especially carbamazepine, were found to be efficacious in such cases.