Three years ago, I launched Esme’s Umbrella at the House of Commons to raise awareness of Charles Bonnet Syndrome (CBS) and to fund research into this distressing condition.

Named after my late mother, for whom CBS tormented her final years with multiple hallucinations, Esme’s Umbrella – which is still just me – has moved apace and today I am hosting the world’s first Charles Bonnet Syndrome Patient Day at Moorfields Eye Hospital.

CBS has been acknowledged by ophthalmologists and optometrists since Charles Bonnet first documented his grandfather’s experience of vivid, silent, visual hallucinations in 1760, but it has always been dismissed as ‘just a side effect’ of sight loss.

It is so very much more than that, as I discovered the day my 92 year-old mother said: “I do wish these people would get off my sofa”. She went on to describe her other ‘visions’, as she called them – a gargoyle-like creature which hopped from table to chair, a Victorian tear-stained street child who followed her everywhere and, sometimes, the whole room or garden morphed into somewhere else. One day, it was an Edwardian funeral procession, complete with plumed horses and the clergy in red cassocks.

The word ‘dementia’ hung between us, even though my mother completed the Telegraph cryptic crossword every day, despite her failing eyesight. After reading a tiny paragraph in a newspaper about sight loss hallucinations, I rang her ophthalmologist – who refused to discuss CBS. Neither her GP nor her optometrist had heard of the condition.

Eventually, I found Dr Dominic ffytche at King’s College London, who is the sole, globally-acknowledged expert in CBS and now my medical adviser. He explained that the silent hallucinations are caused by diminished or lost sight, when the messages from the retina to the visual cortex in the brain slow or stop, but the brain does not. The cells continue to fire up and create their own images.

The frustration of no medication nor medical consultants may be another reason why only 17% of patients receive a warning that CBS might develop. In the last three years, I have listened to people’s experiences and heard the negative impact of CBS on their lives, leaving them frightened, lonely, isolated and – if it is no longer possible to distinguish between what is real and what is not – housebound. Indeed, the images seen can be so horrific that some people contemplate suicide. Fear of being diagnosed with a mental health issue prevents people from confiding in anyone and, if they do visit their GP, a mis-diagnosis is entirely possible – only because CBS is so little known amongst the general medical profession.

Today’s Patient Day is a very exciting and ground-breaking event. Speakers are Dr Dominic ffytche, myself, two researchers from Newcastle University (one funded by TPT, Fight for Sight, National Eye Research Centre, and the other supported by the Macular Society), Dr Mariya Moosajee from Moorfields Hospital, and two people who live with CBS.

I am eternally grateful to all those who have supported me, either with time, money or encouragement. My mother’s final distressing years were not lived in vain and she would be delighted to know that her Umbrella shelters everyone of any age with CBS, those raising awareness or working to find a treatment and a cure – indeed the whole CBS community.

For more information, please email Esme’s Umbrella, visit the Esme’s Umbrella website or call their helpline on 020 7391 3299. Calls are answered by the RNIB Eye Health Team who are working with Esme’s Umbrella.