Charles Bonnet syndrome (CBS) is a common condition among people with poor vision. It is when you experience silent visual hallucinations. These can seem real and can be confusing or frightening. They are caused by the brain trying to ‘fill in’ detail in the blind areas. The hallucinations usually decrease or disappear over time.
Anyone, including children, who has an eye condition that results in sight loss can develop Charles Bonnet syndrome. However, it is more common in older people as they are more likely to have conditions, such as age-related macular degeneration, cataracts, glaucoma or diabetic eye disease, which result in sight loss.
We don’t know why sight loss leads to hallucinations, but it is thought that the brain fills the gaps in your vision by releasing new images or old images that it has stored. This can start in the weeks following your sight loss. You may worry that you have Alzheimer’s disease or a mental health problem, but Charles Bonnet syndrome is a result of the sight loss and is not associated with any other health problem. Symptoms include:
Currently, there is no cure for Charles Bonnet syndrome and no specific medication has been shown to stop the hallucinations. Some medications that are designed to treat epilepsy, Parkinson’s disease and dementia have proved effective for people who are severely affected. Usually, the hallucinations will become less frequent and vivid and may stop altogether. However, they may restart if there is another sudden, significant loss of vision.
There are some things you can try to help relieve your symptoms:
The Macular Society runs a buddy service for people affected by Charles Bonnet syndrome. Telephone the helpline during office hours (Monday to Friday, 9am to 5pm) 0300 30 30 111.