Vision loss can bring phantom images, Blind Low Vision NZ explains

People with vision loss who see things that are not there may have Charles Bonnet Syndrome, a recognised condition, according to Blind Low Vision NZ.

The organisation has published guidance on the condition, known as CBS. It was written by optometrist Danielle Gamlen of Specsavers Brisbane CBD, Australia.

Many people are reluctant to tell family, friends or health professionals about the images, the guidance explains. They worry the hallucinations will be mistaken for mental illness or cognitive decline. As a result, many may experience them alone, without realising the condition is common.

CBS is when people with different levels of vision loss experience visual hallucinations, often called phantom images. The guidance stresses that they are not a sign of a mental disorder.

The experience affects only vision. It does not affect thinking, learning, remembering or using language. People will not hear, smell or taste the hallucinations.

CBS can affect people of any age who have vision loss, though it is commonly reported in adults aged 80 years or older. Hallucinations can occur with varying degrees of vision loss, and more commonly when vision in both eyes is affected. The true number of people affected is likely higher, the guidance notes, because many are unaware of the condition or choose not to report their symptoms.

What causes it

The exact cause is not fully understood, the guidance explains. Experts believe that when the brain receives less visual information because of vision loss, its visual centres may become more active. This can result in images appearing even though nothing is actually there.

The images are not affected by the underlying eye condition. They appear clearer or sharper than everyday vision, so most people with CBS can recognise that the images are not real.

The images can range from simple to abstract, and can be unsettling or even frightening. They may include repeating geometric patterns, faces, people, animals, buildings, landscapes or objects. They do not typically show memories, familiar people or past events.

For some people the same type of image keeps returning, while for others it changes each time. As people learn more and become familiar with their experiences, the images often become less distressing. For many, the hallucinations come and go over months or years, the guidance adds.

What to do

There is currently no cure for CBS, but Blind Low Vision NZ says there are ways to manage it and reduce how distressing the hallucinations may be. Stress, fatigue, illness, social isolation and reduced visual stimulation may make them more noticeable for some people.

People with symptoms should discuss them with their optometrist, GP or low vision service, the organisation advises. These professionals can help confirm the diagnosis, rule out other possible causes and give advice on managing the condition.

Making the best use of remaining vision may also help, according to the guidance. Appropriate spectacles, magnifiers or other low vision aids may reduce how often or how severe the hallucinations are. Simply understanding that they are a common experience for people with vision loss is often enough to help.

Where to find support

Knowing that others share similar experiences can provide reassurance and reduce isolation, the guidance explains. Macular Degeneration New Zealand’s website provides patient-friendly information, helpful for affected people and those who care for them.

Esme’s Umbrella Foundation for Charles Bonnet Syndrome in the UK has a website with a wealth of personal experiences and videos.

Blind Low Vision NZ can provide community support and vision services for people experiencing CBS and vision loss. Its resources include mobility training with a white cane or guide dog, and training on adaptive techniques and technology.

To learn about the support on offer, people can call the Blind Low Vision NZ Contact Centre on 0800 24 33 33.