Charles Bonnet Syndrome
Visual Hallucinations of People with Sight Loss
Sometimes, blind people experience visions or hallucinations. This condition is different from the hallucinations experienced from those with mental health disorders.
Charles Bonnet Syndrome (CBS) is a collection of symptoms in which an individual who has sight problems sees things that he or she knows are not there. These hallucinations can include forms such as patterns, pictures, animals or buildings.
The condition was first described in 1760 by a Swiss philosopher called Charles Bonnet who noted the descriptions of items that were not really there form his blind grandfather.
CBS affects some people with serious sight loss, and usually only those who have lost their sight in adulthood. The visual hallucinations frequently stop within 12 – 18 months.
Causes
Currently, researchers know very little about how the brain interprets the visual information it gets from the eyes so that people can see visual images. It is thought that when people become blind, their brains are not receiving as many images as before, and that sometimes some pictures stored in their brains are released and experienced as though they were seen. Typically, these visual images tend to happen when there is not much else to absorb their attention, for example, sitting quietly in a chair at the end of the day.
The stigma of seeing things
When people first begin to see things, they may worry that there may be something going wrong with their minds – such as a form of mental illness or the start of dementia. For these reasons, some people do not report these symptoms. It is known, however, that having CBS does not increase the likelihood of developing any further medical conditions.
Another reassuring difference between CBS-related hallucinations and the hallucinations associated with mental health issues is that in CBS, the individual quickly appreciate that these visions are not real. This contrasts with some people with mental health problems, and who have difficulty in knowing the difference between what is real and what is not.
The images that people see
In general terms, the images are pleasant, although the effects of seeing things can cause fear and consternation. Visions can include either colored or black and white images and can be believable – or include fantasy images, such as wizards. Visions may also include patterns such as lines, brickwork and mosaics. Pictures usually occur suddenly, and may last a few minutes or several hours before disappearing.
Effects of Hallucinations
The complicated pictures that appear can distort whatever residual sight is present, for example, brickwork in front of the individual, making moving around difficult. A good knowledge of the surroundings can be helpful in dealing with this problem.
The effects of seeing strange things can be disturbing, although some people with this condition can overcome this by recognizing their own visions - discounting them or even addressing them.
Treatment
The knowledge that this is not a sign of mental illness is reassuring for most people with CBS. Usually, the symptoms disappear after 12 – 18 months. For people who are disturbed by these hallucinations, some drugs are available, although none are universally effective.
Some people recommend changing things when the hallucinations appear. For example, turning the light off, if it is on, or getting out of bed, or into it – whichever is different from when the vision occurs. Moving the direction of where one is looking can also be helpful.
Talking over the symptoms with a local doctor will provide support and help.
