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.

We’ve created an information guide that you can download. 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 patterns 

  • 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, and to answer any questions you may have about your sight loss or day-to-day living.

Talk to our eye health team

Information on registering as sight impaired


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.

We will help you maximise your vision and make the most of the sight that you have.

If you haven’t already now would be a good time to join RNIB Connect, our connected community of everyone affected by sight loss.

Make use of our free Talking Books service

Browse products in the RNIB shop

Listen to RNIB Connect Radio

Join the RNIB Connect community


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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