Your questions answered

Illustration of a Charles Bonnet hallucination of a large insect on the dining room floor

On Monday we ran out of time to ask all of your questions as part of our Charles Bonnet Twitter Q&A.

Dr John-Paul Taylor from Newcastle University has therefore answered some of the questions he did not have a chance to answer below.

Why do so many people say they see figures in period costume?

Often this goes along with landscapes and the people are often wearing hats.

Some people speculated hallucinations in CBS may be “prototypes” – if I say to you – imagine a policeman – we will all produce a “prototype” in our head. Hallucinations may be extension of this.

Also in macular degeneration, loss of the cone cells in the eye relative to other cells might make people more prone to seeing brightly coloured hallucinations – like costumes.

How do they differ from migraines or dementia induced hallucinations?

In migraines – the hallucinations tend to be elementary – flashes of light, lines, squiggles etc.

In dementia hallucinations – typically tend to be animals, children, people although often aren’t as detailed as those seen in CBS.

How do they differ from other hallucinations?

Some people regard hallucinations in CBS the equivalent of phantom limb sensation.

When you lose a limb you can still “feel” things. Losing vision may be similar.

Visual hallucinations in other conditions can be associated with other hallucinations e.g. sounds or sensations.

Are there any particular triggers?

Changes in light, environment etc. Stress and tiredness can make things worse. Each person with CBS is often aware of their own “triggers”

What’s going on in my brain when I hallucinate?

We think the brain cells in the visual area are firing too much as a result of a lack of input from the eye.

How can health professionals help raise awareness of Charles Bonnet Syndrome?

Health professionals themselves need to be more aware of the condition. There is currently a lack of understanding out there.

Opticians, ophthalmologists, neurologists and psychiatrists can lead the way. Asking every person with eye disease whether they get hallucinations or not helps.

The Macular Society runs a buddy service for people affected by CBS, where they can put you in touch with someone who's also experienced visual hallucinations for support and reassurance

What possible treatments are there for Charles Bonnet Syndrome?

Understanding that the hallucinations are a normal consequence of vision loss, rather than a mental health problem can really help.

We don’t have any evidence that specific drugs work although we do try a variety and may help some. If the hallucinations are not distressing or disruptive best to avoid trying to treat with drugs.

My colleague Dominic ffytche is looking at how certain eye movements may help reduce the intensity of the hallucinations.

Move your eyes from left to right. Do this once every second 15 times without moving your head, then pause for a few seconds and repeat; it's worth trying this up to four or five times 

Stare at the image and blink rapidly or reach out to touch the vision – try this for a few seconds 

In some people the hallucinations may naturally abate by themselves over time.

What treatments may be available in the future?

We are understanding more about the causes of CBS. Some drugs which act on one brain chemical, serotonin, we think might be helpful and trials are being tested.

Our own research group are looking at using non-invasive brain stimulation methods such as direct current stimulation to reduce overactivity and hallucinations.

What can people do to get rid of hallucinations when they occur?

See above.

What should people do if they’re scared of their hallucinations?

Don’t be alone – talk to someone. Seek out health care professionals who are familiar with the disease.

The Macular Society have a fantastic helpline and there is lots of information on the internet. Esme’s umbrella is another great organisation.

Who is Charles Bonnet?

A Swiss scientist first described visual hallucinations in his grandfather Charles Lullin.

However the term “Charles Bonnet Syndrome” was not coined until 1967 by another Swiss scientist, George De Morsier.