Quick Facts and Management of Charles Bonnet Syndrome

charles bonnet syndrome

Hallucination vs. Illusion:

  • Hallucination is sensory perception of things that are not there and persist with eye closure.
  • Illusion is misperception of viewed objects.

What is Charles Bonnet Syndrome (CBS)?

  • CBS is classified under hallucination and may occur in patients with visual acuity loss, visual field loss or reduced contrast sensitivity (1, 2).
  • It may also occur in patients with relatively good vision, but have increased emotional distress and decreased quality of life (3).
  • Patients with CBS see images that include complex colored patterns, but know that the images are NOT real.
  • Images of people are most common, followed by animals, plants or trees and inanimate objects (5).
  • Images are often pleasant and do not scare patients.
  • These hallucinations are only visual and not occur with other senses, e.g. hearing, smell or taste.
  • Some people experience CBS for anywhere from a few days up to many years, and these hallucinations can last from seconds to most of the day.
  • CBS is often described as similar to “the phantom limb” where patients with limb amputation still feel the sensation that the missing limb is attached to the body (3).


  • One theory of CBS is the release theory where sensory deprivation leads to the release of subconscious perceptions.
  • Any pathology affecting the visual pathway (retina, optic nerve, brain) can lead to CBS.
  • Common conditions causing CBS are (1,4): age-related macular degeneration, glaucoma & cataract.


  • 11%-15% of people with vision loss (3).
  • Mean age of incidence is 75-80 years old.
  • Impaired vision is usually 20/60 or worse in the better eye.


  • CBS is arrived via diagnosis of exclusion.
  • We must rule out neurologic, psychiatric, metabolic and other toxic disorders.
  • It is important to carefully review the patient’s prescription medications and ask about the use of any illicit drugs.
  • Though there is no treatment for CBS, it is vital to educate and reassure patients of their condition.
  • Referral to patient’s PCP and neurologist for appropriate work-up.

Tips for Patients with CBS:

  • Closing or blinking eyes may alleviate hallucinations (5).
  • Additional lighting, encouraging patients to stay physically and mentally active and participating in social activities can reduce the frequency and vividness of the images (6).

1. Jacob A, Prasad S, Boggild M, Chandratre S. Charles Bonnet syndrome–elderly people and visual hallucinations. BMJ 2004; 328:1552.
2. Jackson ML, Bassett K, Nirmalan PV, et al. Contrast sensitivity and visual hallucinations in patients referred to a low vision rehabilitation clinic. Br J Ophthalmol. 2007;91:296–8.
3. Scott IU, Schein OD, Feuer WJ, Folstein MF. Visual hallucinations in patients with retinal disease. Am J Ophthalmol. 2001; 131 (5): 590
4. UpToDate. Visual release hallucinations (Charles Bonnet Syndrome). Obtained on [April 28, 2013]
5. Vukicevic M, Fitzmaurice K (2008) “Butterflies and black lacy patterns: the prevalence and characteristics of Charles Bonnet hallucinations in an Australian population”. Clinical and Experimental Ophthalmology. 36:659-65
6. The Lighthouse Clinicians’ Guide to Low Vision Practice

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