Butterflies and black lacy patterns: the prevalence and characteristics of Charles Bonnet hallucinations in an Australian population

Abstract

Background: Charles Bonnet Syndrome (CBS) is characterized by vivid, elaborate and recurrent visual hallucinations in psychologically normal people. It most often occurs in older, visually impaired persons. The prevalence of the syndrome has been reported at 1-40% in Asia, Europe and North America. The aim of this study was to examine the prevalence and characteristics of CBS in the older aged, visually impaired population in Australia.

Methods: Two hundred consecutive patients attending ophthalmology clinics aged more than 60 years with best-corrected visual acuity of 6/12 or less were screened for CBS. Those who reported experiencing visual hallucinations were asked to participate in the project. They were then interviewed and asked demographic, general health and visual hallucination-related questions. A group of 30 non-hallucinating participants was chosen for comparison of demographic data.

Results: The prevalence was found to be 17.5%. Participants experiencing hallucinations were predominantly female with a mean age of 77.7 years. Correlations were found between the living situation, level of education and characteristics of the hallucinations such as the duration, length of time the participant had been experiencing them and their frequency.

Conclusion: The prevalence of CBS in the older-aged, low-vision population is 17.5%. Several demographic and syndrome-specific characteristics were found to be consistent enabling a profile of a CBS sufferer in this group of participants to be compiled.