Vivid visual hallucinations without other psychopathology have been reported for several hundred years. However, there is no consensus on whether these hallucinations should be considered a separate syndrome, the Charles Bonnet syndrome, or whether eye disease or brain disease is a necessary or exclusionary criterion for diagnosing this syndrome. In an attempt to resolve these issues, this article reviews the literature on isolated visual hallucinations and presents follow-up data from six cases. Criteria for diagnosing the Charles Bonnet syndrome are suggested.