Charles Bonnet syndrome

Understanding Charles Bonnet Syndrome

Charles Bonnet syndrome (CBS) is a common condition among people who’ve lost their sight.

It causes people who have lost a lot of vision to see things that aren’t really there – medically known as having a hallucination.

CBS hallucinations are only caused by sight loss and aren’t a sign that you have a mental health problem.

Download our Understanding Charles Bonnet syndrome guide

Our Understanding Charles Bonnet syndrome guide is accredited by the Royal College of Ophthalmologists. It’s designed to give you a detailed understanding of your eye condition and helpful advice on next steps.

You can also contact us directly if you’re concerned about the condition and its impact on your day-to-day life.

Understanding Charles Bonnet syndrome

CBS tends to begin in the weeks and months following your sight getting worse.

The main cause of CBS is loss of vision and how your brain reacts to this loss.

Research suggests that when you see real things around you, the information received from the eyes stops the brain from creating its own pictures. When you lose your sight your brain doesn’t receive as much information and fills in these gaps by releasing new fantasy pictures, patterns or old pictures that it has stored.

What's it like to experience Charles Bonnet syndrome

Bee has glaucoma. She first experienced CBS when she was shopping. She explains the types of hallucinations she gets and how she copes.


If you start to notice any type of hallucination it’s important to make an appointment with your doctor as soon as you can.

There isn’t one test your doctor can do to find out whether you have CBS, but they can rule out other causes of hallucinations like Alzheimer’s and mental health problems.

CBS hallucinations only affect your sight, which means that you don't hear, smell or feel things that aren't there. Also people with CBS tend to be aware that what they are seeing isn’t real and they don’t usually develop complicated ideas of why they are seeing things.

By talking to your doctor about your hallucinations they should be able to rule out the other causes.

Types of hallucinations 

The hallucinations caused by CBS can appear in lots of ways including:

  • simple shapes and dots of colours
  • simple pattern
  • detailed pictures of people, animals, landscapes and buildings.

Coping with hallucinations 

It’s normal to be worried, confused or frightened when you see things that aren’t really there. It’s important to remember that CBS hallucinations are only caused by sight loss and aren’t a sign that you have a mental health problem.

When you first develop CBS your hallucinations might happen quite often, but over time they can become less frequent. For some people they can carry on for longer, and it’s not unusual if you still have an occasional hallucination some years after they first started.

Our understanding CBS guide has lots of tips for coping with hallucinations from exercises that can help to dealing with  your hallucinations. 


Although there’s currently no medical cure, CBS usually improves with time. 

There’s no proven drug that can stop CBS hallucinations. In some cases drugs for other conditions have been tried to help people who are very upset or confused by their CBS hallucinations. These drugs are designed for people with more serious conditions like dementia or epilepsy, and are usually very strong with a lot of side effects.

Some common medications people take as they get older can interact and make your CBS hallucinations more frequent. If you’re not sure if the medication you’re taking is making your CBS worse, ask your GP.

If you download our Understanding CBS guide you can get advice on non medical ways to cope with your hallucinations.   

Recently diagnosed with Charles Bonnet syndrome

Trying to adjust after a diagnosis of CBS can seem overwhelming at first, and it might involve some changes to your life. We’re here to support you every step of the way – just give our Helpline a call. 

You might also find it helpful to talk to our Eye Health team about your eye condition, get support from our Sight Loss Counselling service, or find out how to register as sight impaired.

Below are some guides that may be useful:

Getting emotional support

Benefits, concessions and registering as sight impaired

For information about Northern Ireland please download our Benefits, Concessions and Certification in Northern Ireland leaflet: 

You can get support with your eye condition with RNIBGet in touch

If you've got any questions, speak to us by calling our Helpline on 0303 123 9999.

"Knowing RNIB is there is so reassuring, like a comfort blanket." 
Peter Seaman

Living confidently with Charles Bonnet syndrome

Living with CBS shouldn’t mean an end to doing most of the things you like to do. You can contact our Helpline for support, or start by reading our guides on making the most of your sight and on enjoying leisure when living with sight loss.

Making the most of your sight

Leisure pursuits when you have sight loss

If you haven’t already, why not join RNIB Connect and get connected to other people affected by sight loss locally and across the country? Or try our free Talking Books service to enjoy reading in an accessible format, or tune into RNIB Connect Radio to hear news, information and advice for people affected by sight loss.

Products from our shop that can help

Helpful organisations

Esme's Umbrella is a campaign group to build up a greater awareness of Charles Bonnet syndrome.

NHS Choices has information and advice on Charles Bonnet syndrome.

How to get involved

About this guide

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