Charles Bonnet Syndrome: When Vision Loss Leads to Hallucinations

Charles Bonnet Syndrome (CBS) is a fascinating yet often misunderstood condition that affects people with significant vision loss. Named after the 18th-century Swiss philosopher who first described it (Charles Bonnet), CBS causes individuals to experience visual hallucinations despite having no mental illness or cognitive impairment.

What is Charles Bonnet Syndrome?

CBS is a condition that occurs in people who have lost a substantial amount of their vision, typically due to eye diseases such as macular degeneration, cataracts, glaucoma, or diabetic retinopathy, but any cause of vision loss could potentially lead to CBS, even a brain injury. The hallucinations experienced by those with CBS can range from simple patterns to complex, lifelike images of people, animals, or places.

Symptoms of Charles Bonnet Syndrome

The primary symptom of CBS is the presence of visual hallucinations. These hallucinations have several distinctive characteristics:

- They are purely visual and do not involve other senses

- They can be simple (patterns, shapes, or lines) or complex (people, animals, objects, or places)

- The images may be still or moving and can appear in color or black and white

- Hallucinations typically last for a few minutes to several hours

- Most importantly, individuals with CBS are aware that these hallucinations are not real especially once diagnosed

Causes and Risk Factors

The exact cause of CBS is not fully understood, but researchers believe it's related to the brain's response to vision loss. When the eyes stop sending visual information to the brain, the visual cortex may become hyperactive, creating its own images to fill the void.

Risk factors for developing CBS include:

- Sudden or severe vision loss

- Vision loss in one or both eyes

- Advanced age, as vision problems are more common in older adults, but CBS can occur in children

Living with Charles Bonnet Syndrome

It was initially believed that hallucinations caused by CBS would go away on their own within 12 to 18 months. However, for most individuals it doesn’t. In fact many individuals experience hallucinations for years or decades. While there is no cure for CBS, understanding the condition can help reduce anxiety and improve quality of life.

Some strategies that may help manage CBS include:

- Changing the environment (e.g., turning lights on or off, moving to a different room)

- Moving the eyes from side to side

- Engaging in activities that stimulate the brain, such as listening to audiobooks or socializing

- Attend virtual or in person CBS support groups to hear what others are going through and share your experiences

- Here is a full podcast episode discussing various coping mechanisms and strategies for managing CBS.

Conclusion

Charles Bonnet Syndrome is a unique condition that highlights the complex relationship between our eyes and our brain. While it can be disconcerting to experience visual hallucinations, it's important to remember that CBS is not a mental health disorder. It’s a medical condition. With proper understanding and management, individuals with CBS can learn to cope with their symptoms and maintain a good quality of life.

If you or someone you know is experiencing visual hallucinations along with vision loss, it's crucial to consult with a healthcare professional for proper diagnosis and support. However, many healthcare professionals don’t know about CBS, so Mary Carmel’s Light and Esme’s Umbrella, two organizations that assist people with CBS, have created information letters that you can bring to your doctors visits to educate them and their staff about this condition:

U.S. Letter to Doctors

UK Letter to Doctors