An Overview of Charles Bonnet Syndrome

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Charles Bonnet syndrome, otherwise known as CBS, is a condition that affects cognitively healthy—most often elderly—people with partial or total vision loss. Those living with CBS often experience very vivid, visual hallucinations that can range from simple to complex and can last anywhere from a few minutes to several hours, days, or even years. Although CBS affects people with vision impairment, it does not affect those born with vision issues—only those who have sudden vision loss or age-related vision issues.

Those living with Charles Bonnet syndrome know their hallucinations aren’t real, so the disease has not been linked with cognitive conditions such as psychosis, schizophrenia, or dementia, which can also cause visual hallucinations. However, many cases of CBS go unreported for fear of being misdiagnosed with one of these conditions. Under-reporting makes it extremely difficult to determine the actual prevalence of CBS.

Because CBS is often linked to more serious, chronic disorders like stroke or macular degeneration, it’s important to take charge of your condition and seek treatment at the onset of symptoms.

Symptoms

The most notable symptoms of Charles Bonnet syndrome are visual hallucinations. People living with CBS may experience two different categories of hallucinations:

  • Simple hallucinations: These hallucinations can include shapes, patterns, flashes of light, and lines, among other non-formed objects.
  • Complex hallucinations: These hallucinations can be fully-formed and include images of people, animals, insects, scenes, repeating patterns, and everyday objects.

People living with CBS also report seeing their hallucinations in both color and black and white. And while the hallucinations are reportedly not disturbing, some may find it unsettling to see a person, animal, or foreign object in their home.

The timing, frequency, and intensity of hallucinations can vary greatly from person-to-person. Many people living with CBS, however, experience hallucinations upon waking and can identify a pattern in the timing and frequency of their hallucinations after some time.

Because CBS is brought on by other conditions that result in vision loss, it’s important to look out for symptoms of the underlying condition, too. Strokes, macular degeneration, cataracts, diabetic retinopathy, and other common conditions can lead to the development of Charles Bonnet syndrome, among other serious disorders.

If you or a loved one begins to experience vivid, visual hallucinations following sudden or age-related visual impairment, be sure to note the timing, frequency, and intensity of the hallucinations, as well as any other recent health issues or events. This information can help healthcare providers rule out other disorders, and best treat the underlying health issue that resulted in vision loss. 

Understanding the Different Types of Hallucinations

Causes

There isn’t a single known cause of Charles Bonnet syndrome. As previously mentioned, CBS can be brought on by other health conditions that damage vision, including:

  • Stroke
  • Macular degeneration
  • Diabetic retinopathy
  • Retinal vein occlusion
  • Occipital stroke
  • Surgical complications resulting in vision impairment

Although Charles Bonnet syndrome has been linked to certain health conditions, researchers still aren’t sure why people with vision impairment can experience visual hallucinations—but there are theories. One common theory suggests that when a person’s retinal cells can no longer send or receive images, the brain begins to create its own “phantom” images—similar to phantom limb pain reported by people who have lost limbs.

What Are the Causes of Hallucinations?

Diagnosis

Because Charles Bonnet syndrome can be linked to more serious, chronic conditions, it’s important to see your doctor at the onset of symptoms. Taking charge of your condition early on can help prevent other health concerns down the road.

When you go to your appointment, be sure to bring a list of symptoms, including descriptions of hallucinations as well as their timing and frequency, any medications you’re currently taking, and information about any other health events that may have contributed to vision loss or impairment.

There isn’t a single tool or test your doctor will use to diagnose you or your loved one with Charles Bonnet syndrome. Rather, they’ll most likely conduct a physical exam and an eye exam, and ask for details about the visual hallucinations. Some doctors may request an MRI scan or memory exercise to rule out other cognitive issues.

Treatment

Currently, there’s no cure for Charles Bonnet syndrome. Most treatment options aim to alleviate symptoms when they occur and make the condition more manageable.

If you’ve been diagnosed with CBS, your doctor may recommend:

  • Practicing optimal eye care and regular visits to your ophthalmologist: Treating the cause of vision impairment and improving visual ability is one of the best ways to manage Charles Bonnet syndrome. It’s been reported that effective treatment of vision loss can reduce the severity and frequency of symptoms.
  • Avoiding triggers for CBS: Some people living with CBS experience intensified hallucinations when they feel stressed, anxious, or isolated. Taking the proper steps to avoid these triggers can help prevent episodes.
  • Exercising your eyes—and other senses: Rapid eye movements and slow blinking can help alleviate the symptoms of CBS. Some doctors also recommend stimulating your other senses (with music, audiobooks, podcasts, or hands-on activities) during a hallucination.
  • Certain prescription drugs: Antidepressants and anticonvulsants are sometimes used to treat CBS, but are generally reserved for very severe cases that have not responded to more conventional treatment options.  

Because several conditions can lead to the development of Charles Bonnet syndrome, treatment options for associated symptoms will vary greatly. Your doctor will determine a treatment plan based on the original cause of vision impairment (like a stroke), as well as medical history and lifestyle.

Always talk to your doctor or ophthalmologist before undergoing any kind of treatment for Charles Bonnet syndrome or its associated health conditions.

A Word From Verywell

Like any condition affecting the vision and brain, Charles Bonnet syndrome can be a scary diagnosis. But it’s important to remember that this condition is largely benign and occurs in physically and cognitively healthy individuals. It is, however, vital to treat the root cause of your vision impairment so you can avoid other health concerns down the road. Take good care of your eyes and visit your ophthalmologist regularly for the most successful management of CBS.

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Article Sources
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  • Baba Awoye Issa and Abdullahi Dasliva Yussuf. Charles bonnet syndrome, management with simple behavioral technique. J Neurosci Rural Pract. 2013 Jan-Mar; 4(1): 63–65. DOI: 10.4103/0976-3147.105618.

  • Menon GJ, Rahman I, Menon SJ, Dutton GN. Complex visual hallucinations in the visually impaired: the Charles Bonnet Syndrome. Surv Ophthalmol 2003;48:58-72. DOI: 10.1016/S0039-6257(02)00414-9.