Complex visual hallucinations (Charles Bonnet syndrome) in the hemianopic visual field following occipital infarction

Charles Bonnet syndrome is characterised by the occurrence of complex visual hallucinations in the presence of normal cognition in elderly individuals. It commonly happens following conditions where there has been a profound loss of vision or interruption of visual input into the occipital cortex. It is important to distinguish this largely innocuous condition from psychiatric conditions that exist in the same age group. This article describes a rare variant of this condition where such hallucinations occur in the hemianopic visual field of a patient with an occipital infarct whose visual acuity is largely unimpaired. The article details the various conditions where this phenomenon has been experienced; the theories that have been postulated for its aetiology and the treatment options. The variations of this case from the commonly observed scenarios are highlighted questioning previously held convictions as well as providing an insight into the widening spectrum of the phenomenon as more cases are described. The article hopes to raise awareness of this condition, which is much commoner than perceived by healthcare practitioners, as most patients in that age group are reluctant to be forthcoming with their symptoms for fear of being diagnosed with a psychiatric disorder. (c) 2007 Elsevier B. V. All rights reserved.