title: An examination of the relationship between low vision and Charles Bonnet syndrome.
abstract: OBJECTIVE
  In recent years, the Low Vision Clinic (LVC) appeared to have a large percentage of patients admitting to phantom vision (Charles Bonnet syndrome [CBS]). The objective of this study was to learn more about CBS from an ophthalmological perspective, as research has been conducted primarily by other specialists.
  
  
  METHODS
  Large-scale prospective study using a cohort of low-vision and normal-vision subjects.
  
  
  METHODS
  Two hundred fifty-eight low-vision and 251 control subjects (with little or no vision loss) were enrolled.
  
  
  METHODS
  A comparison of visual acuity, ophthalmic conditions, eye treatments, medications, mental state, general health, socialization, etc., was undertaken, and other factors influencing the hallucinations were recorded.
  
  
  RESULTS
  CBS was present in 34% of LVC subjects and in <2% of the general population with little or no vision loss. Many subjects had unformed hallucinations; bright lights or spot-like images should not be overlooked because they could be determined to be hallucinations upon further questioning of the patient. CBS occurred in subjects with visual acuity from 20/40 to 20/1600; subjects were twice as likely to have CBS if their visual acuity was between 20/301 and 20/800. The prevalence of CBS did not differ significantly by cause of visual problem. Thirty-four percent of people were distressed about their initial hallucination; many did not consult a doctor for an explanation, and if they did, many did not receive an adequate explanation.
  
  
  CONCLUSIONS
  This large-scale study shows that CBS is connected with a low vision level; thus, patients should be told about the common possibility of hallucinations.
authors.affiliation: Low Vision Clinic, Eye Care Center, Saskatoon City Hospital, Saskatoon, Sask. duke597@shaw.ca
authors.forename: George
authors.initials: G
authors.lastname: Gilmour
authors.forename: Colleen
authors.initials: C
authors.lastname: Schreiber
authors.forename: Cecil
authors.initials: C
authors.lastname: Ewing
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006212:Hallucinations / Q000503:physiopathology* / Q000523:psychology; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013577:Syndrome; D015348:Vision, Binocular / Q000502:physiology; D015354:Vision, Low / Q000503:physiopathology* / Q000523:psychology; D014792:Visual Acuity / Q000502:physiology