Sight-loss hallucinations 'more serious'

The research, conducted by King’s College London in conjunction with the Macular Society, documented the experiences of 492 visually impaired people who had experienced visual hallucinations.

They suggest there is a serious discrepancy between medical opinion and the realities of the condition.

The phenomenon, known as Charles Bonnet Syndrome, is widely considered by the medical profession to be benign and short-lived. However, the research shows that 80% of respondents had hallucinations for five years or more and 32% found them predominantly unpleasant, distressing and negative.

Tony Rucinski, Chief Executive, the Macular Society, said: “It is essential that people affected by sight loss are given information about Charles Bonnet Syndrome at diagnosis or as soon after as possible.

“Losing your sight is bad enough without the fear that you have something like dementia as well. We need medical professionals to recognise the seriousness of Charles Bonnet Syndrome and ensure that people don’t suffer unnecessarily. More research is also needed to investigate Charles Bonnet Syndrome and possible ways of reducing its impact.”

The study described this group of people as having “negative outcome Charles Bonnet Syndrome”. The group was more likely to have frequent, fear inducing, longer duration hallucinations, which affected daily activities.

They were more likely to attribute hallucinations to serious mental illness and were less likely to have been warned about the possibility of hallucinations before they started.

Of respondents, 38% regarded their hallucinations as startling, terrifying or frightening when they first occurred and 46% said hallucinations had an effect on their ability to complete daily tasks.
36% of people who discussed the issue with a medical professional said the professional was “unsure or did not know” about the diagnosis.

People with macular disease are particularly prone to Charles Bonnet hallucinations. They are thought to be a reaction of the brain to the loss of visual stimulation. More than half of people with severe sight loss experience them but many do not tell others for fear they will be thought to be mentally ill.

The Macular Societyis trying to raise awareness of Charles Bonnet Syndrome so that people with sight loss know what to expect and why it is happening.

Age-related macular degeneration (AMD) affects the central vision and is the most common cause of sight loss in the UK. Nearly 600,000 people have late-stage AMD today and more people will become affected as our population ages. Around half will have hallucinations at some stage.