What are the other Names for this Condition? (Also known as/Synonyms)

• CBS (Charles Bonnet Syndrome)
• Visual Release Hallucinations

What is Charles Bonnet Syndrome? (Definition/Background Information)

• Charles Bonnet Syndrome (CBS) is a condition in which an individual with partial or complete vision loss (partial or total blindness) experiences complex visual hallucinations. The condition is relatively common among the visually-impaired
• In general, Charles Bonnet Syndrome affects older individuals, specifically those with central or peripheral vision loss that may occur from conditions, such as age-related macular degeneration, retinitis pigmentosa, and optic neuritis, among several others
• The complex hallucinations associated with Charles Bonnet Syndrome usually consist of small animated (cartoon) images or faces; the affected individuals are generally aware that the hallucinations are not real
• The frequency of visual hallucinations varies from one individual to another. Some may experience the hallucinations intermittently, while others experience them daily or continuously. The duration may last from a few minutes to even several years
• The exact underlying cause of Charles Bonnet Syndrome is not known. Treatment is generally geared toward addressing pre-existing conditions that may lead to loss of vision. Providing emotional support is also an important aspect of the treatment

Who gets Charles Bonnet Syndrome? (Age and Sex Distribution)

• Charles Bonnet Syndrome may occur in any individual with partial or complete vision loss
• However, it is more common among the elderly population (age range 70-85 years) due to the increased likelihood of vision loss with aging. Up to 40% of older adults may be affected by this condition
• Caucasian females over the age of 65 years (the population most affected by age-related macular degeneration) are more frequently affected than any other racial/ethnic group

What are the Risk Factors for Charles Bonnet Syndrome? (Predisposing Factors)

The most common risk factors for developing Charles Bonnet Syndrome include the following conditions that cause either central or peripheral vision loss:

• Age-related macular degeneration; an eye disorder with compromised central vision
• Glaucoma; increased pressure in the eye due to fluid build-up, which can damage the optic nerve
• Cataracts or clouding of the lens in the eye that is usually seen in old age
• Diabetic retinopathy: A complication of long-term diabetes caused by damage to blood vessels in the retina
• Retinitis pigmentosa; the degeneration of light-sensing cells in the retina
• Optic neuritis; a condition resulting in inflammation of the optic nerve
• Retinal vascular occlusion; blockage or clot in a blood vessel of retina
• Stroke, due to interrupted blood flow to a part of the brain

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Charles Bonnet Syndrome? (Etiology)

• Presently, the exact cause of the visual hallucinations in those with Charles Bonnet Syndrome is unknown
• Although inconclusive, certain theories have been proposed including a relationship between vision loss and decreased sensory input to the brain, resulting in a more sleep-like state that produces images similar to dreams

What are the Signs and Symptoms of Charles Bonnet Syndrome?

The signs and symptoms of Charles Bonnet Syndrome may vary among the affected individuals. It has been reported that the images often ‘fit in’ with natural objects seen with the remaining vision.

The signs and symptoms of CBS may include:

• Variable and complex hallucinatory images
• The visual hallucinations are most likely to occur while alone in dim lighting and when lacking distractions
• Cartoon images and faces of people; the most commonly reported image descriptions
• Images of colored patterns, plants, and animals
• Signs and symptoms of any underlying condition may be noted

Normally, the other senses, such as taste, hearing, smell, and touch, remain unaffected.

How is Charles Bonnet Syndrome Diagnosed?

The diagnosis of Charles Bonnet Syndrome is based on the following tests and exams:

• Complete physical examination
• Assessment of the affected individual’s signs and symptoms, including his/her report of hallucinatory images that match the most common descriptions of previous cases
• Evaluation of medical history
• Eye examinations
• Lab tests, including total blood count and urine analysis
• Imaging tests, such as computed tomography or magnetic resonance imaging scan of head and neck region
• Tests to rule out other neurological conditions
• A differential diagnosis to eliminate Lhermitte’s hallucinosis (a hallucinatory condition seen in elderly adults) may be considered before arriving at a definitive diagnosis.

Note: Charles Bonnet Syndrome is sometimes misdiagnosed by healthcare providers as dementia, delirium, or other psychotic disorders.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Charles Bonnet Syndrome?

The complications of Charles Bonnet Syndrome may include:

• Anxiety that the condition is somehow related to one’s mental health
• Depression
• Reduced quality of life
• In rare cases, progression to dementia: One study linked many individuals with CBS to developing Lewy body dementia later on. Therefore, CBS may be a precursor to Lewy body dementia, or maybe even considered an early stage of the disease.

How is Charles Bonnet Syndrome Treated?

The treatment measures for Charles Bonnet Syndrome may include:

• Treating the underlying cause of vision loss such as age-related macular degeneration, cataract, glaucoma, etc. The restoration of vision has been shown to reduce or eliminate the visual hallucinations from Charles Bonnet Syndrome, in some cases
• Vision aids to improve existing vision
• Providing patient reassurance and emotional support
• Administration of anti-epileptic or anti-anxiety medications, as needed
• The following steps may be considered by the patient or patient cartaker:
  • Eye exercises that include moving the eyes rapidly in different directions
  • Looking away or walking away from the hallucinatory images
  • Changing the lighting in the room
• Repetitive trans-cranial magnetic stimulation

How can Charles Bonnet Syndrome be Prevented?

Currently, the exact cause of Charles Bonnet Syndrome is unknown; and hence, there are no methods or guidelines are available for its prevention. However, the following steps may help minimize the risks for developing Charles Bonnet Syndrome:

• Undertaking regular visits to an ophthalmologist
• Seeking medical attention for conditions that are known to cause vision loss
• Complete smoking cessation
• Keeping blood pressure under control
• Including green leafy vegetables in the diet on a regular basis
• Identifying and avoiding triggers for hallucinations, which may include stress, anxiety, and social isolation

What is the Prognosis of Charles Bonnet Syndrome? (Outcomes/Resolutions)

• The prognosis of Charles Bonnet Syndrome is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have a better prognosis than those with severe symptoms and complications. The condition may persist for many years in some individuals
• Most individuals with Charles Bonnet Syndrome remain indifferent about their hallucinations, but providing reassurance that CBS is not a mental health condition can help improve their quality of life to a certain extent

Additional and Relevant Useful Information for Charles Bonnet Syndrome:

• Charles Bonnet, a Swiss philosopher, first described this eye disorder in the late 18^th century; however, it was first accepted as a health condition only in late 20^th century
• It is thought that many individuals with Charles Bonnet Syndrome do not report their visual hallucinations out of fear of being diagnosed with a mental condition or being considered psychotic. Thus, the exact prevalence rate of CBS is not fully known