By: Judith Potts

The number of people affected by sight loss in the UK is set to double to 4 million by 2050 and, of the five senses, sight is the one which most people fear losing the most.

Sight loss goes hand in hand with loneliness, but a further step into isolation comes with the onset of Charles Bonnet Syndrome (CBS). As sight diminishes or is lost entirely, the messages from the retina to the visual cortex slow or stop – but the brain does not. It fires up and produces vivid, silent, visual hallucinations which range from disturbing to terrifying. CBS can affect anyone of any age who has lost 60% of sight from eye disease, cancer, stroke, accident, diabetes or another health condition. Even if the patient sees pleasant images, the frequency with which they appear makes them a constant irritant and interruption to everyday life. For others who experience multiple hallucinations, it becomes impossible to distinguish between what is real and what is not, so they become housebound. Not being able to tolerate what they see, or being embarrassed by explicit images, leaves others contemplating suicide.

Too many people receive no warning from their ophthalmologist that CBS might develop. It might not, but should it do so, patients wrongly assume that the hallucinations are part of a mental health issue. Only 17.2% **of people with sight loss receive this warning from their ophthalmologist. Countless others are left to live their lives in hallucination-filled worlds, not daring to confide in anyone. Given that there is also a significant increase in people over the age of 45 living on their own, the social implications of sight loss, CBS and isolation are obvious.

Mis-diagnosis is common because CBS is not widely recognised by GPs, hospital doctors, nurses or care home staff. Should the word ‘hallucinations’ be mentioned, the patient will be sent down the mental health path – sometimes on a one-way ticket. The cost to the NHS of wasted medication and incorrect referrals must be enormous.

Dr Dominic Ffytche, Reader in Visual Psychiatry, at King’s College London, is the sole, globally-acknowledged expert in CBS. In 1998, he began his SHAPED programme of research into visual hallucinations, establishing the difference between those experienced in CBS, Parkinson’s and Dementia.

Thanks to donations from three UK eye charities, (Fight for Sight, The Thomas Pocklington Trust and the National Eye Research Centre), my campaign, Esme’s Umbrella has its name attached to CBS research at Newcastle University, but no other social or clinical/medical research is being conducted anywhere else. With the growing number of sight loss diagnoses (not least because of Type 2 diabetes) so much more is needed.

Having heard the experiences of thousands of people with CBS – including my own mother, Esme – I urge the NHS to lead an awareness campaign to ensure that every GP, hospital doctor, nurse or carer is aware of CBS and resources are no longer wasted on mis-diagnosis. A proper pathway for diagnosis, treatment and care is vitally needed.

Acknowledgement of CBS as a condition in its own right, not just as a side effect of sight loss, is being considered by the World Health Organisation. At the moment, there is no one to whom a patient with CBS can be referred. The provision of specialist CBS nurses would help to alleviate the anguish of patients, who are being left in limbo, only garnering information and comfort from Esme’s Umbrella and other eye charities with Helplines. Obviously, there is a limit to what can be achieved from a telephone call.

One simple step forward would be to add a tick box to the Certificate of Visual Impairment, which ophthalmologists complete to register patients as blind or partially sighted. This would be a reminder of the importance of explaining CBS.

There are an estimated 1 million people in the UK living with CBS. Losing sight is bad enough, but when the hallucinations begin, a person’s quality of life takes a further down-turn. CBS and sight loss must be included by the DCMS in its campaign to alleviate loneliness.

Considering that Charles Bonnet documented the condition in his grandfather in 1760, it is shocking that over 250 years later, we are not much further forward in understanding what he described as the ‘theatre of the mind’.

** Figure from the Macular Society