A retired teacher has spoken about the hallucinations she suffers as a result of a medical condition which researchers have finally recognised as more serious than previously thought.

Joan Dearden, 84, of Clayton Heights, Bradford, has had Charles Bonnet Syndrome for more than ten years and it has left her suffering hallucinations which means it appears small tortoise-like animals are running around the carpet of her home.

It is a consequence of macular degeneration but until recently the medical profession assumed it was a short-lived phenomenon which caused no real harm.

However, new research by King’s College London and published in the British Journal of Ophthalmology both lasts longer than previously thought and has more damaging effects.

Details were taken from almost 500 people with the condition, including Joan who has been affected for more than a decade.

Doctors widely assumed the condition lasted only months but eight in ten of those questioned have been affected by hallucinations for more than five years and a third found the experience unpleasant, distressing or negative.

Joan said: “The first hallucination I had was when I went to catch a bus. It looked as if there was a man standing by the bus stop, but then he vanished. At first I was really puzzled as to where he went.

“A couple of years later I started regularly seeing a face that appeared to be just out of reach. I have also seen little animals that look a bit like tortoises running along the carpet.

“I’m a retired science teacher, so when I was diagnosed with macular degeneration I did a lot of reading into the subject. This meant that I knew about the possibility of hallucinations. Some people are terrified when they experience them.

“I feel strongly that more people should know about Charles Bonnet Syndrome. There must be so many people who are experiencing it and are scared because they don’t realise what it is.”

Of those with Charles Bonnet Syndrome, 38 per cent regarded hallucinations as startling, terrifying or frightening when they first occurred and 46 per cent said hallucinations affected their ability to complete daily tasks.

Macular disease causes a loss of sight and it is believed hallucinations are the brain’s reaction to the loss of visual stimulation.

More than half of people with severe sight loss experience hallucinations but many do not tell others for fear they will be seen as mentally ill.

Tony Rucinski, chief executive of 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.”

The Macular Society’s helpline is 0300 3030 111.