What is Charles Bonnet Syndrome?

Charles Bonnet syndrome (CBS) is a common condition among people who have lost their sight. It causes people who have lost a lot of vision to see things that aren’t really there, known as visual hallucinations
CBS can be distressing, but many people find that the hallucinations can get less frequent with time. It was initially thought that hallucinations resolved within 12 to 18 months, but a recent study found that most people still have occasional hallucinations five years after they first started.

People who have CBS may have lost a lot of their vision from an eye condition, such as age-related macular degeneration, cataract, glaucoma or diabetic eye disease. Many of these conditions are more common in older people so many people who have CBS are older. However, anyone of any age, including children, may develop this condition as any eye condition that causes sight loss can trigger CBS.

It’s thought that there are more than 100,000 cases of CBS in the UK. Some research suggests that up to 60 per cent of people who are experiencing serious sight loss may develop it.


Symptoms of Charles Bonnet Syndrome

The visual hallucinations caused by CBS can vary and can range from simple shapes and dots of colours, simple patterns, straight lines or a network of branches, to detailed pictures of people, animals, insects, landscapes and buildings. When you have lost a large amount of your vision it may be difficult to see everyday things, but you may find that your CBS hallucinations are very detailed, and much clearer than your normal vision. The images can appear “out of the blue”, lasting for just a few minutes or in some cases, several hours.

At times, the hallucinations may fit alongside the background you are looking at, making them feel quite real, like seeing cows in a field when the field is actually empty or seeing a fence across the pavement. At other times, they will seem totally unreal, like seeing fantasy images such as dragons.

When you first develop CBS your visual hallucinations may happen quite often, you may see things every day and for long periods of time. Your CBS may stay like this for a number of months, but over time the hallucinations may become less frequent and they may eventually stop. However, some people’s hallucinations carry on for longer and you may find that you are prone to hallucinations every now and again.


Types of hallucinations

The kinds of things people see with CBS hallucinations seem to fall into two broad types:

  • Simple repeated patterns
  • Complex hallucinations of people, objects and landscapes.

Causes of Charles Bonnet Syndrome

The main cause of CBS is loss of vision and how your brain reacts to this loss. Exactly how sight loss leads to hallucinations isn’t really known, but research is slowly revealing more about how the eye and the brain work together.

Current research seems to suggest that when you are seeing real things around you, the information received from your eyes actually stops the brain from creating its own pictures. When you lose your sight, however, your brain is not receiving as much information from your eyes as it used to. Your brain can sometimes fill in these gaps by releasing new fantasy pictures, patterns or old pictures that it has stored. When this occurs, you experience these images stored in your brain as hallucinations. CBS tends to begin in the weeks and months following a deterioration in your sight.


Treatment of Charles Bonnet Syndrome

Currently there is no medical cure for CBS. When you experience CBS, the most effective form of treatment can come from knowing that the condition is not a mental health problem or a symptom of another disease but is due to sight loss. Knowing that CBS usually improves with time (even if it doesn’t go away completely) may also help you cope with the hallucinations. Having information on CBS and sharing your experiences with friends or family can also help.

Although there is no proven drug you can take to stop CBS hallucinations, some drugs for other problems have been successful in helping some people. The drugs that have been tried are usually very strong and are designed for people with epilepsy, Parkinson’s disease, dementia or mental health problems. All these drugs can have serious side affects and should only be used under proper supervision and probably only for people who are very upset or confused by their CBS hallucinations.

Some common medications people take as they get older can interact when they’re taken together. This can 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 to review your medication. This may help to lower the frequency of your hallucinations.


What do I do now?

If you have been diagnosed with Charles Bonnet Syndrome, there are many ways in which Galloway’s can help you and your loved ones come to terms with the diagnosis and can offer simple practical help with living with the diagnosis and coping with every day life.

Galloway’s runs a support group specifically for Charles Bonnet Syndrome sufferers.  To find out more about the group, or CBS in general, get in touch with our Low Vision Team on 01772 744148