Charity funds Charles Bonnet Syndrome studies

Dr Amit Patel

Fight for Sight is highlighting the need for more awareness and research into the visual hallucinatory condition, Charles Bonnet Syndrome (CBS).

The eye research charity, together with partners Blind Veterans UK, Esme’s Umbrella and Health and Care Research Wales, is funding two research projects – at Cardiff University and the University of Oxford – to investigate the cause of the visual hallucinations associated with CBS, with the hope of eventually finding a cure.

CBS is a common side-effect of sight loss in which people experience visual hallucinations. The kinds of things people see with CBS is thought to fall into two main types:
1. Simple repeated patterns or shapes, such as grids or brickwork patterns
2. Complex hallucinations of people, objects and landscapes

CBS hallucinations can be very detailed, and much clearer than the person’s everyday vision. The images appear very suddenly, lasting for just a few minutes or in some cases, several hours. The syndrome can happen to people with good mental health who have no history of psychiatric problems. Usually, people with CBS are aware – or can learn to recognise – that what they’re seeing isn’t real even though it’s very vivid.

There is currently not enough data to show how many people in the UK have CBS, the charity says, but it is estimated to be hundreds of thousands. In spite of this, scientists still do not understand why these hallucinations occur. There is also little awareness about the condition, and those who experience it often report that they were never made aware that this was something common in people with sight loss.

Dr Amit Patel lost his sight unexpectedly in 2015 and since then he regularly experiences visual hallucinations. As a trauma doctor, Amit had a limited knowledge of CBS before he experienced it himself, having come across it very briefly in his studies at medical school.

He said: “One day, not long after I lost my sight, I was walking down the stairs in my house and this girl suddenly appeared in front of me. I realised it was the girl from the horror movie ‘The Ring’. The hallucination only lasted a few seconds, but it was enough for me to fall down the stairs. At that point I wasn’t really comfortable talking to people about what I was going through in losing my sight and I was very much in my head and in a bad place, so I put it down to that. After a few weeks though this same girl kept appearing and that’s when I knew I was having visual hallucinations and I thought that it may be Charles Bonnet Syndrome.”

The Covid-19 pandemic and subsequent lockdown has only exacerbated Amit’s experience of CBS and he says he has had a lot more hallucinations in the last few months, and particularly in the early days and weeks of the lockdown.

Likewise, campaign group Esme’s Umbrella – which was set up to help support people living with CBS and works closely with Fight for Sight – says its helpline has received double the number of calls over the past five months, with some people saying the stress and isolation they’ve experienced during the pandemic has turned otherwise fairly benign images into frightening ones.

Fight for Sight is urgently calling for more funding to be invested in vital research for CBS, which can sometimes be mistakenly confused with the onset of dementia.

A team of researchers at Cardiff University, funded by Fight for Sight and Health and Care Research Wales, has developed a novel method to induce controlled hallucinations in the lab, which will allow them to explore the mechanisms underlying the syndrome. This project will use fully-sighted people to investigate the possibility that peripheral (‘side’) vision is more ‘suggestible’ than central vision. The team are testing a hypothesis that following long-term central vision loss, patients with CBS pay more attention to their peripheral vision, which is more reliant on expectation and previous experience than central vision, and therefore prone to hallucinatory experiences.

While at the University of Oxford, researchers funded by Fight for Sight, Blind Veterans UK and Esme’s Umbrella, will use MRI scans to compare the brains of people with and without CBS to look at how they differ. In particular, they will measure the levels of chemicals in the visual areas of the brain to see whether they are abnormal in CBS, leading to the hallucinations.

It is hoped these research studies will provide insight into the cause of CBS hallucinations, which will help inform larger studies in the future and eventually to test whether there are interventions to help improve the condition.

Chief executive of Fight for Sight, Sherine Krause, said: “So much more needs to be done to understand Charles Bonnet Syndrome. This is an area of research that little is known about and has largely been neglected, so we are very pleased to fund these two important research studies. With a better understanding of the causes of Charles Bonnet Syndrome, we will be one step closer to developing a treatment and eventually a cure for the condition. This is just one area where much greater investment in eye research is needed to ensure we can continue transforming the lives of people with sight loss.”

Head of programmes at Health and Care Research Wales, Michael Bowdery, said: “We are delighted to be working with Fight for Sight to support research into a condition that affects so many people but for which there is currently no known treatment or cure. We wish Matt and the team at Cardiff University the very best of luck.”

For more information on Charles Bonnet Syndrome, or to donate to research into the condition, visit Fight for Sight’s website.