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Disease Profile

Charles Bonnet syndrome

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

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ICD-10

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Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

CBS

Categories

Eye diseases

Summary

Charles Bonnet syndrome (CBS) is a disease in which visual hallucinations occur as a result of vision loss. CBS is not thought to be related to psychosis or dementia and people with CBS are aware that their hallucinations are not real.[1][2][3] The hallucinations people with CBS experience can be described as simple or complex. Simple hallucinations include shapes and patterns, while complex include images of people, vehicles, animals, and plants. Hallucination episodes can range from a few seconds to hours and may recur over the course of several days to years.[2] 

The cause of CBS is not well understood, but it is thought to be related to the brain continuing to interpret images, even in their absence.[4][3] There are many underlying diseases of vision loss that are associated with CBS, such as macular degeneration and stroke. Hallucinations may resolve in instances where the the underlying vision issue can be corrected (such as with cataracts). Treatment differs depending on the impact symptoms have on a person's life. Some people are taught to block their hallucinations, while others may benefit from antipsychotic medications.[1]

Symptoms

Hallucinations associated with Charles Bonnet syndrome (CBS) can be simple, non-formed images such as lines, light flashes, patterns, or geometric shapes. They also can be complex, such as images of people, animals, or scenes. They are usually not disturbing and do not involve other senses. People with CBS are generally aware that the hallucinations are not real and do not have an underlying psychological disease or dementia.[1][2]

The timing and frequency of hallucinations can vary widely. The hallucinations tend to occur upon awakening. They usually last several minutes, but can be seconds or hours. Typically, there is a distinctive pattern to the timing and frequency of the hallucinations. The degree and complexity of the hallucinations also vary among individuals, but no association has been found between the complexity of the hallucinations and the severity of visual loss.[1][4][3]

Associated symptoms depend upon the underlying disorder producing the visual loss. For example, strokes involving the visual pathways produce vision loss and sometimes other neurologic deficits, while macular degeneration and diabetic retinopathy produce loss of vision loss without neurologic deficits.[1]

Treatment

While there is currently no single treatment that is effective for all cases of Charles Bonnet syndrome, there are steps that patients can take that might have a positive effect:[1][5]

  • Optimal eye care and regular visits to the ophthalmologist
  • Low vision aids to help maximize any existing vision
  • Avoidance of conditions known to aggravate CBS such as stress, anxiety, social isolation, and sensory deprivation
  • Reassurance that the hallucinated images are benign and that treatment is an option
  • Medications including olanzapine, quetiapine, carbamazepine, clonazepam, and donepezil
  • Certain rapid eye movements or blinking to help suppress the hallucination
  • Repetitive transcranial magnetic stimulation

The Charles Bonnet Syndrome Foundation has additional information.

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Social Networking Websites

      Organizations Providing General Support

        Learn more

        These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

        Where to Start

        • VisionAware is a support and information resource offered by the American Foundation for the Blind. They provide an information page on Charles Bonnet syndrome.

          In-Depth Information

          • PubMed is a searchable database of medical literature and lists journal articles that discuss Charles Bonnet syndrome. Click on the link to view a sample search on this topic.

            References

            1. Pelak VS. Visual release hallucinations (Charles Bonnet syndrome). UpToDate. Waltham, MA: UpToDate; June 7, 2016; https://www.uptodate.com/contents/visual-release-hallucinations-charles-bonnet-syndrome.
            2. Pang L. Hallucinations Experienced by Visually Impaired: Charles Bonnet Syndrome. Optom Vis Sci. December 2016; 93(12):1466-1476. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5131689.
            3. Duffy MA. Charles Bonnet Syndrome: Why Am I Having These Visual Hallucinations?. VisionAware. https://www.visionaware.org/info/your-eye-condition/guide-to-eye-conditions/charles-bonnet-syndrome/124. Accessed 3/30/2018.
            4. P. Ricard. Vision loss and visual hallucinations: the Charles Bonnet syndrome. Community Eye Health. March 2009; 22(69):14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2683559/.
            5. Treatments. Charles Bonnet Syndrome Foundation. https://www.charlesbonnetsyndrome.org/index.php/cbs/treatments. Accessed 1/26/2017.

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