There is increasing evidence that visual hallucinations, some of which can be quite disturbing, are a common feature of sight loss of any nature and at all ages. Bearing this in mind, it is important for eye care professionals (ECPs) to be aware of this and feel confident asking questions about it with their patients. Too many patients suffer Charles Bonnet syndrome (CBS) in silence, fearful that their problem is a sign of mental illness and that admission might result in them losing a degree of independence.
In this short article, I will describe a recent case of mine where I identified a patient as having CBS and who benefited from a specific strategy to minimise their hallucinations.
Case Study
In June this year, I undertook a domiciliary assessment of MG, a housebound 81-year-old female. Prior to the pandemic lockdown, she had been able to attend clinic in person, but since damaging her hip in a fall last year, mobility had become increasingly difficult and she was now confined to her flat for most of the time.
MG had longstanding dry age-related macular degeneration and had been registered as sight impaired for over five years. After assessing her vision and discussing various strategies to make sure she had best use of her remaining vision, I asked her if she had ever noticed any unusual, strange or worrying images or hallucinations that she might want to talk about. I made it clear that the reason I was asking this was that many people with vision like hers reported this and described some common examples, such as colours, shapes, people or animals.
At this point, MG looked at me in amazement and admitted this had started a few weeks ago. She also confessed she had not mentioned it before because she had assumed that it was a sign that she might be developing dementia, something she feared but of which there was otherwise no evidence.
Her story described how, since her first major fall, she found moving around her flat a little more difficult. In January, she managed to trip over a stool in the kitchen and had fallen to the floor with the stool landing on top of her. When she managed to get up, move to the living room and sit down, she noticed a tall man who she did not recognise standing by her television and staring at her. She rubbed her eyes and looked again to find he had disappeared. She then told me that, since then, he often appears, usually in the same place and usually when she was tired. As time has gone on, she finds his appearance to be less alarming, but she does not like it and would rather he never came back.
I had just issued her with an illuminated 24DS hand magnifier, the LED light of which was quite bright. I suggested that, if he were to appear again, try switching on the magnifier, holding it under her chin and shining the light upwards towards her face. This might make him go away.
One month later, on a telephone consultation, MG told me that now she knows the man is simply an illusion, one her active brain is using to compensate for sight loss, she has seen him appear fewer and fewer times. And, when he does appear, the trick with the light works, something she was very pleased about.
What is Charles Bonnet Syndrome?
Charles Bonnet was an 18th century Swiss lawyer and philosopher who studied natural science in his spare time (figure 1). He first described visual hallucinations in a patient who did not have dementia or mental illness. That patient had lost vision due to cataracts and had since reported hallucinations of people, birds, carriages, buildings and vividly coloured tapestries.
The estimated prevalence of CBS in those with vision loss varied widely, but is thought to be as high as 30%. For those with best acuity of 6/18 to 6/60, the risk appears to be around 10 to 20% risk, while for those with 6/60 or worse, the risk of developing CBS is nearer to 60%. It can occur in any age group and from any eye disease. Hallucinations are visual and there is no auditory, smell or touch component. Also, unlike hallucinations associated with psychosis, the sufferer is far less likely to believe they really exist, though this does not necessarily make them less disturbing.
In 2019, this author and colleagues undertook a small-scale audit of patients with sight loss seen in our low vision clinic.1 Of those, we found 30% had some form of CBS. Interestingly, of these, 44% reported their CBS without prompting while 56% only revealed their hallucinations after prompting. These figures supported the already significant evidence base suggesting that, unless we ask about CBS, we might not find out it is present.
What can be done?
As well as its high prevalence, another feature of CBS is how variable it is from person to person, both in terms of how much anxiety it causes and also in how effective interventions are in reducing its frequency. Some general points, however, are accepted. For example, the hallucinations are often worse during a quiet time, so keeping the brain/mind active may help to keep the hallucinations at bay. Often the hallucinations are associated with a particular location, as with the case presented here.
Because each person is different, it is worth knowing a few coping strategies as not everything works for each patient. The following may be recommended to people with CBS:
- Reach out towards the hallucination and try and touch it, or sweep your hand to brush away the image.
- Shine a torch upwards from below your chin in front of your eyes, but not directly into the eyes.
- If sitting, try standing up and walking round the room. If standing, try sitting.
- Walk into another room or another part of the room.
- Turn your head slowly to one side and then the other. Dip your head to each shoulder in turn.
- Stare straight at the hallucination for a prolonged period.
- Change whatever it is you are doing at that moment, for example turn off or turn on the television/radio/music.
- Change the light level in the room. It might be dim light that is causing the hallucinations. If so, turn on a brighter light.
- Blink your eyes once or twice, slowly.
I was once lucky enough to interview Professor Dominic Ffytche, Professor of Visual Psychiatry at Kings College London, a world renowned authority on CBS and a medical adviser to the charity Esme’s Umbrella (see later). Ffytche has devised an eye movement exercise that he recommends and which has a good degree of success. He advised the following:
- When the hallucination starts, look from left to right about once every second for 15 seconds without moving your head.
- If the hallucination continues, have a rest for a few seconds and then repeat the eye movements.
- You may need four or five repeats of the eye movements to have an effect.
- If after this the hallucination persists, there is no point in continuing and another strategy might instead be tried.
Medication
A number of systemic medications are known to increase the likelihood of CBS. These include:
- Anti-muscarinic/cholinergic drugs used to treat urinary tract disease.
- Atropine eye drops.
- Lansoprazole, commonly used to treat gastric problems.
- Tricyclic antidepressants.
- Synthetic opiates.
Medications and treatments that have been shown to help minimise the effect of CBS include the following:
- Anti-epilepsy drugs; these reduce brain activity.
- Dementia drugs; these boost the levels of acetylcholine which can help with CBS.
- Selective serotonin reuptake inhibitors (SSRIs).
- Non-invasive brain stimulation, such as transcranial magnetic stimulation (TMS) to reduce hyperactivity.
Impact of Covid-19
A recent study has shown that the Covid-19 lockdown has exacerbated the impact of CBS upon those with the condition.2 The study looked at 45 patients with CBS with a mean age of 69.3 years. Of these, 60% were female and 42.2% had macular disease. Each was given a questionnaire asking about features of their hallucinatory experiences during the Covid-19 lockdown and what they thought might have triggered episodes. Key findings were:
- 56% of the cohort reported an increased frequency of visual hallucinations.
- 47% reported changes in their nature (becoming more sinister).
- 53% reported changes in their emotional response to the hallucinations (more fearful or anxious).
- 67% experienced greater feelings of loneliness during lockdown.
- 60% had not accessed support services about their CBS.
The triggers for CBS the patients perceived as most significant were:
- Loneliness (67%).
- Less physical exercise (47%).
- Watching and reading chronic stressful news (31%).
- Reduced access to healthcare (24%).
All four of these were also reported by MG, my patient.
Management
Once CBS has been confirmed, strategies like those listed above are very useful and well worth telling patients about. Most authorities suggest that, where CBS is suspected, referral to a GP is warranted to confirm it and to rule out other possible underlying causes, such as adverse drug reactions, psychoses and central nervous system disease.
The influence of social isolation is interesting. There is clearly a link between life expectancy, sight loss and therefore the incidence of CBS. However, it is likely that the increase in social isolation among those with sight loss, especially the elderly, is also contributory to the rise in CBS cases.
We should, therefore, be able to recommend options such as community support groups, social and sensory team workers, ECLOs and so on. And many of the sight loss charities can help with CBS, especially Esme’s Umbrella.
Esme’s Umbrella
Judith Potts, an actor and presentation coach, set up the charity Esme’s Umbrella in November 2015 to raise awareness about CBS and to offer support to those with the condition and information to those in a position to help them. She named the charity after her mother who had struggled throughout her life with CBS at a time where such support was not to be found.
- Check out the website for a wealth of useful information: https://charles bonnetsyndrome.uk
References
1 Jessa Z, Gow L, Harvey W. (2019). An audit of self-reported vs practitioner prompted symptoms of CBS. Poster presentation, European Society for Low-vision Research and Rehabilitation Conference. (PDF available on request: william.harvey@rnib.org.uk)
2 Jones L, Ditzel-Finn L, Potts J, et al. Exacerbation of visual hallucinations in Charles Bonnet syndrome due to the social implications of COVID-19. BMJ Open Ophthalmology, 2021;6:e000670.