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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.
Resources
The Charles Bonnet Syndrome Foundation website
Understanding Visual Hallucinations
Family physician awareness of Charles Bonnet syndrome
Charles Bonnet syndrome frequently asked questions
Charles Bonnet syndrome information - About Gary Cusick
Cleveland Clinic - Charles Bonnet Syndrome
Fighting Blindness Canada - Diseases Spotlight: Charles Bonnet Syndrome
CNIB Events - Seeing Things: Charles Bonnet Syndrome Group
Vision Loss and Charles Bonnet Syndrome - Audio Podcast
Oliver Sacks TED Talk: What hallucination reveals about our minds