What is Charles Bonnet Syndrome? Understanding Visual Hallucinations in Sight Loss

Learn about Charles Bonnet Syndrome and the links to dementia.

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Imagine sitting in your living room and suddenly seeing a cat walk across the floor — except there is no cat. Or looking out of your kitchen window and noticing a building site where your garden should be. For some people, it might be pink fluffy clouds drifting through the air, or strangers in elaborate period costumes appearing in the room.

These are not dreams or imagination. They are examples of Charles Bonnet Syndrome (CBS) — a condition that remains widely under-recognised despite affecting an estimated hundreds of thousands to around one million people across the UK, including both adults and children.

What is Charles Bonnet Syndrome?

Charles Bonnet Syndrome is a condition that can occur following any level of sight loss. It is recognised by eye care and medical professionals worldwide and causes visual hallucinations that are often:

• Highly detailed
• Vivid and realistic
• Silent (they do not involve sound)

These hallucinations can vary greatly from person to person. Some people see:

• Patterns such as grids, dots, or zig-zags
• Brightly coloured shapes
• People, sometimes in historical or unfamiliar clothing
• Landscapes or dream-like scenes
• Animals or fantasy creatures

For many, these images appear suddenly and without warning.

Why Does CBS Happen?

CBS is not caused by a mental health condition. Instead, it is the brain’s response to reduced visual input.

When the eyes stop sending clear information, the brain can begin to “fill in the gaps”, creating images on its own. In simple terms, the visual system is still active — it just no longer has accurate input to work with.

Common Misconceptions

One of the biggest challenges surrounding CBS is misunderstanding.

Many people who experience hallucinations worry they are:

• “Going mad”
• Developing dementia
• Experiencing a psychiatric condition

This fear can prevent individuals from speaking out or seeking help, particularly due to concerns about being judged or misdiagnosed.

For children, this can be especially distressing, as they may struggle to explain what they are seeing or feel frightened by the experience.

Diagnosis and Medical Advice

There is no specific test for Charles Bonnet Syndrome.

However, it is still essential to speak to a GP or healthcare professional. Visual hallucinations can sometimes be linked to other conditions, including:

• Infections
• Neurological conditions
• Medication side effects

Ruling these out is an important step before confirming CBS.

If hallucinations are accompanied by confusion, memory problems, changes in behaviour, or involve other senses such as hearing voices, urgent medical advice should be sought.

Living with CBS

There is currently no specific cure for Charles Bonnet Syndrome, but symptoms often improve over time. Many people find that:

• Hallucinations become less frequent over time
• The brain gradually adapts to changes in vision
• Episodes become easier to manage with the right strategies

Understanding the condition is often one of the most powerful tools in reducing fear and anxiety.

Managing and Coping with CBS

While hallucinations can’t always be prevented, there are simple techniques that can help interrupt or reduce episodes:

• Try to touch or brush away the image
• Adjust lighting — brighter environments can help
• Blink repeatedly or move your eyes side to side
• Stand up and move around
• Distract your brain (TV, music, clapping, conversation)
• Draw or describe what you are seeing
• Change the lighting or introduce a new light source

Different techniques work for different people, so it’s worth experimenting to find what helps most.

The Role of Emotional Wellbeing

CBS symptoms can be influenced by overall wellbeing. Hallucinations may worsen during periods of:

• Stress
• Fatigue
• Illness
• Low mood

Focusing on self-care can make a meaningful difference. Helpful approaches include:

• Mindfulness and meditation
• Gentle exercise such as yoga
• Maintaining routines
• Staying socially connected
• Engaging in enjoyable activities

Support and Awareness

Support is available, and no one should feel they have to manage CBS alone.

You can seek help from:

• Your GP
• Eye Clinic Liaison Officers (ECLOs)
• CBS support groups and Galloways

Raising awareness is key. The more people understand CBS, the less fear and stigma surrounds it.

Final Thoughts

Charles Bonnet Syndrome can be confusing, frightening, or even fascinating — but it is important to remember this:

It is a natural response to sight loss, not a mental illness.

With the right information, support, and coping strategies, many people learn to manage CBS with confidence.

If you or someone you support is experiencing visual hallucinations, speaking openly is the first step toward reassurance and understanding.

References

• NHS. Charles Bonnet Syndrome. Available at: https://www.nhs.uk
• Royal National Institute of Blind People (RNIB). Charles Bonnet Syndrome. Available at: https://www.rnib.org.uk
• Esme’s Umbrella. Understanding Charles Bonnet Syndrome. Available at: https://www.charlesbonnetsyndrome.uk
• Menon GJ. (2005). Complex visual hallucinations in the visually impaired. Archives of Ophthalmology.
• Teunisse RJ et al. (1996). Visual hallucinations in psychologically normal people. The Lancet.