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Charles Bonnet Syndrome (CBS) is a common condition among people with significant sight loss. It is characterized by visual hallucinations. It is not a mental health disorder, nor a symptom of dementia or other illness. It is specifically related to sight loss. Symptoms can however, cause confusion and concern among those who experience it.
- The exact cause of CBS hallucinations is not known. Experts note that the brain attempts to fill in information that would normally be obtained by the eyes.
- While CBS is believed to affect approximately 1/3 of people with sight loss, it is not known why some experience it while others do not.
- CBS is not widely known. Research is ongoing.
- CBS can occur across all ages, and all sight loss conditions including macular degeneration, glaucoma and diabetic retinopathy.
- People with CBS become aware that what they are seeing is not real, even though imagery can appear detailed and clear.
- CBS hallucinations affect only sight and are not accompanied by smell, sound or touch.
- Hallucinations can appear at any time; last for a few seconds or be of extended duration. CBS can occur for days or years.
- Imagery can be pleasant, neutral or disturbing.
- At times images may appear to have a gliding type movement.
- People experiencing CBS may be hesitant to discuss it and may fear getting diagnosed with serious mental health conditions.
- An eye doctor will likely rule out other conditions that could cause visual hallucinations. In the absence of other conditions, they may diagnose CBS. It is important to consult with your doctor to confirm a diagnosis of CBS.
- CBS can typically take the form of one or all of the following: Simple, Complex, Panoramic.
Simple: images of wallpaper, text, scaffolding, shapes, lines, colours.
Complex: faces, people in costume, animals, miniature people, surreal images like dragons, marching soldiers, cartoons.
Panoramic: landscapes, entire scenes.
Managing Charles Bonnet Syndrome
- Adjust lighting in the room: Example, if you are experiencing a hallucination in dim light, turn on a bright light.
- Try gently shifting your eyes left to right for a few seconds for up to one minute without moving your head.
- Create a distracting activity: move to another location, engage in a task, turn on the radio.
- Consider telling family and friends about what you see and discuss your CBS with others who are experiencing it.
Depictions of Reported Imagery from People with Lived Experience of CBS
The imagery below is shared from the Visions of Charles Bonnet Syndrome PHD research in progress, by Vicky Hamilton.
The depictions are a co-creation between researcher and participant with lived experience of CBS, and the creative work is continuously changing. The research website is cbsvisions.com.
These images demonstrate how someone with Charles Bonnet Syndrome might experience a CBS hallucination.
Here is the link for the first image.
Image Description: An image shows a grocery store scene superimposed with a kaleidoscope of colours in blue and orange. The CBS image of shifting colours blocks the actual scene in reality. While the imagery may appear pleasant in the video, to the person experiencing it, it can be frightening.
Here is the link for the second image.
Image Description: A dog appears in a kitchen doorway, where there is no dog in reality. The dog then vanishes after a few minutes. Seeing the image of the dog that is not there, can evoke a range of emotional responses in a person with CBS.
Resources
CNIB Events - Seeing Things: Charles Bonnet Syndrome Group
The Charles Bonnet Syndrome Foundation website
Charles Bonnet syndrome frequently asked questions
Charles Bonnet syndrome information - About Gary Cusick
The Charles Bonnet Syndrome Podcast
Cleveland Clinic - Charles Bonnet Syndrome
Co-creative research - the Visions of Charles Bonnet
Family physician awareness of Charles Bonnet syndrome
Fighting Blindness Canada - Diseases Spotlight: Charles Bonnet Syndrome
Oliver Sacks TED Talk: What hallucination reveals about our minds
Understanding Visual Hallucinations
Vision Loss and Charles Bonnet Syndrome - Audio Podcast
York University Perceptual Neuroscience Laboratory – Current Projects