Charles Bonnet Syndrome

Individuals with Charles Bonnet Syndrome (CBS) may experience psychovisual disturbances causing them to see things that are not there. 

Last Updated: March 27, 2023

What is Charles Bonnet Syndrome?1-3

Charles Bonnet Syndrome (CBS) is a medical condition affecting some people with significant vision loss. Individuals with CBS may experience psychovisual disturbances causing them to see things that are not there. Due to a low awareness and reporting of this elusive condition, the psychovisual symptoms of CBS may be confused with mental illness. It is important to note that CBS causes visual disturbances in patients without mental illness.

What causes CBS?1-3

Just as amputees may experience phantom limb sensations, individuals with CBS may see images after significant vision loss occurs. The lack of visual data from the eyes causes the brain to attempt to fill in the blank, resulting in made-up or recalls of stored images for the individual to see.

What are the symptoms of CBS?1-3

People with CBS are generally aware that what they are seeing is not real. The psychovisual disturbances are only visual, so people with CBS do not hear, smell, or feel things that are not there. The psychovisual disturbances are often abstract in nature and may include colours, shapes, people, animals, cartoons, objects, and complex scenes. Images can appear at any time, lasting from a few seconds to several hours. Individuals with CBS report variable reactions to their psychovisual disturbances, ranging from pleasant and positive experiences to frightening and negative ones.

Who is at risk?1-3

One in five people that experience some form of vision loss and/or blindness may experience CBS, regardless of age. Loss of sight from macular degeneration, cataracts, glaucoma, or diabetic retinopathy can increase the risk of experiencing CBS. CBS can begin weeks or months after significant vision loss, and it may spontaneously resolve after a period of time in some cases.

Can CBS be treated?1-3

There is no cure or medical treatment for CBS, but there are ways to help manage the condition. Experiencing psychovisual disturbances can be scary and confusing, especially when dealing with loss of vision. Recognizing the cause of the problem and talking about it with family, friends, therapists or doctors can help individuals with CBS feel re-assured and relieved. Changing the environment, adjusting the light condition, reducing fatigue, minimizing stress, moving the eyes, closing the eyes and low-vision rehabilitation have been reported to be helpful for individuals with CBS. 
 

Who is Charles Bonnet?

Charles Bonnet was a Swiss philosopher in the 1700s who documented the visual hallucinations experienced by his grandfather, who also suffered vision loss from cataracts.4 The medical term Charles Bonnet Syndrome was coined almost 200 years later in the 1900s by George de Morsier, a French-Swiss neurologist.5

If you are experiencing psychovisual disturbances as a result of vision loss, book an appointment today to speak with your local optometrist.

References

  1. Menon GJ et al. Complex visual hallucinations in the visually impaired: the Charles Bonnet Syndrome. Surv Ophthalmol. 2003;48(1):58-72.
  2. Fernandez, Antony, Gil Lichtshein, and W. Victor R. Vieweg. The Charles Bonnet syndrome: a review. J Nerv Ment Dis. 1997;185(3):195-200.
  3. Schadlu AP et al. Charles Bonnet syndrome: a review. Curr Opin Ophthalmol. 2009;20(3):219-222.
  4. Damas-Mora J et al. The Charles Bonnet syndrome in perspective. Psychol Med. 1982;12:251-261.
  5. Kester EM. Charles Bonnet syndrome: case presentation and literature review. J Optom. 2009;80:360-366.

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