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Charles Bonnet Syndrome: The Mind Plays Tricks with Low Vision Patients

Charles Bonnet Syndrome: The Mind Plays Tricks with Low Vision PatientsFried eggs draped over the objects on the desk. Smaller-than-life-sized people in ancient Roman dress streaming out of the television during the morning weather report. Colorful birds flying through the bathroom, roosting on the shower curtain.

Detailed hallucinations of unknown people, faces, buildings, cartoons, children and animals, patterns and designs the viewer knows aren’t real occur spontaneously in about one-third of people who develop low vision due to illness or injury, according to the Royal National Institute of Blind People.

Most people who experience such hallucinations think they have gone mad, because they don’t realize they are experiencing Charles Bonnet Syndrome (CBS). Often, patients remain silent and fearful about their symptoms, which can lead to much quiet suffering (Lighthouse International; Menon, Rahman, Menon, and Dutton 2003). This can develop into clinical depression or an anxiety disorder. Much of this suffering might be avoided if CBS were more widely known by the people most at risk for it and their care team members.

Named for the Swiss naturalist who first described it in 1780 (Bellows), CBS is not widely known. “Physician awareness and empathy are the cornerstones of management” for CBS (Menon, Rahman, Menon, and Dutton 2003). Sadly, too few medical professionals and most patients and their families have never heard of this syndrome, and even fewer know how to approach it with a likely-to-succeed approach. This two-part article will deal with education and empathetic management.

Why does it happen, this “phantom eye” phenomenon? One theory is that the brain is filling in information where there is none due to diminished vision. A parallel can be drawn to the neurological mixup that occurs with phantom limb. The syndrome results in sensation and pain as if a missing limb were still present.

An extension of this theory is offered on the website of the Royal National Institute of Blind People on their website:

Current research seems to suggest that, when you are seeing real things around you, the information received from your eyes actually stops the brain from creating its own pictures. When you lose your sight, however, your brain is not receiving as much information from your eyes as it used to. Your brain can sometimes fill in these gaps by releasing new fantasy pictures, patterns or old pictures that it has stored. When this occurs, you experience these images stored in your brain as hallucinations. CBS tends to begin in the weeks and months following a deterioration in your sight.

For more information about the possible biological mechanisms in CBS, see neurologist Oliver Saks’s informative and charming (though slightly controversial) talk explaining Charles Bonnet Syndrome neurology, which is linked here.

While the description “sees hallucinations” is accurate with CBS, it is not adequate to describe the full experience, nor is it sufficient to help differentiate CBS from other types of hallucinations. The following — especially taken together — are considered distinctive of Charles Bonnet Syndrome:

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  1. There is clear awareness by the viewer that the visions are not real, though initially he or she may second-guess that conclusion (Lighthouse International; Murphy, 2012; Menon, Rahman, Menon, and Dutton 2003).
  2. The visions are not of recognizable people, places or events (RNIB).
  3. There is no accompanying rich emotional or sensory experiences or memories other than the visual images (RNIB).
  4. The viewer is not drawn into the hallucination and does not believe it to be real – there is a sense of detached watching, with the imagery lacking personal meaning.
  5. The objects, people and animals may appear smaller or larger in scale than normal, or may appear normal-sized; seeing in miniature scale is also possible (RNIB).
  6. The visions may interact and conform to actual surroundings; for example, people may enter through a door that is in reality present (RNIB).
  7. The visions are detailed, clear, vivid, and complex, not vague or indistinct (RNIB; Bellows). Images are often much more clear than the person’s actual remaining vision allows them to perceive (RNIB).
  8. Disembodied or distorted faces may be seen, as well as patterns, people, buildings, landscapes, cartoons, children and animals (RNIB; Saks in Kiume, 2009).
  9. The visions are most likely to happen during “down” times as opposed to ones of active engagement (Lighthouse International; Murphy, 2012).
  10. CBS usually lasts no more than 12-18 months (Lighthouse International; Murphy, 2012).
  11. Anticonvulsants and haloperidol might be prescribed, as they reduce these episodes in some people (Menon, G., Rahman, I., Menon, S., and Dutton, G.; Roberts, 2004).

The second part of this article will focus on empathetically managing this syndrome, and ways that the stress and trauma of CBS can be reduced. Also included will be an exploration of ways some patients, their families and physicians have successfully interrupted or reduced these hallucinations.



Bellows, A. Chuck Bonnet and the Hallucinations. Retrieved September 5, 2012 from

Light House International. Charles Bonnet Syndrome. Retrieved September 5, 2012 from

Menon, G., Rahman, I., Menon, S., and Dutton, G. (January-February 2003). Complex visual hallucinations in the visually impaired: the Charles Bonnet Syndrome, abstract. Surv Ophthalmol 48 (1): 58-72. Retrieved September 5, 2012 from

Murphy, C. When Seeing Isn’t Believing: Charles Bonnet Syndrome. (August 9, 2012) Scientific American. Retrieved on September 5, 2012 from

Royal National Institute of Blind People (RNIB). Retrieved on September 5, 2012 from

Roberts, D. Charles Bonnet Syndrome (CBS). (September, 2004). MD Support. Retrieved on September 5, 2012 from

Saks, O., in Kiume, S. (2009). Seeing Hallucinations While Blind. Psych Central. Retrieved on September 4, 2012, from

Charles Bonnet Syndrome: The Mind Plays Tricks with Low Vision Patients

Deborah Bier, PhD

Deborah Bier, PhD, has been a holistic psychotherapist and homecare agency director for 25 years. Certified by the Commonwealth of Massachusetts's Office of Elder Affairs and the Massachusetts Alzheimer's Association, she trains dementia caregivers and coaches dementia families. Her particular expertise is in helping multi-generational families apply wellness approaches to managing chronic illness. She holds a doctorate in therapeutic counseling.and is a widely published writer and speaker specializing in health and healing. Find her website at

APA Reference
Bier, D. (2018). Charles Bonnet Syndrome: The Mind Plays Tricks with Low Vision Patients. Psych Central. Retrieved on August 7, 2020, from
Scientifically Reviewed
Last updated: 8 Oct 2018 (Originally: 17 May 2016)
Last reviewed: By a member of our scientific advisory board on 8 Oct 2018
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