Charles Bonnet Syndrome

What is Charles Bonnet Syndrome?

Charles Bonnet syndrome (CBS) is a type of medical disorder which primarily involves the eyes. This condition was first discovered in 1760 by Charles Bonnet (a Swiss philosopher) and thus named after him. Bonnet was able to discover this condition because his own grandfather actually suffered from the same condition. His grandfather lost his vision to cataract and later on he reported seeing things which are not actually present. However, it was only in 1982 that this condition was officially accepted by the English psychiatry.

This condition actually involves visual loss that is accompanied by liliput hallucinations. The characteristic of the hallucinations is described such because this usually include things which are actually smaller than the usual sizes of objects. This is not considered to be a type of mental disorder because the affected person is well aware that the hallucinations are not real. People especially those who are over 65 are slightly at risk of developing such condition and in a current study in Australia the incidence was found to be at around 10 to 40%. There are actually unreported cases of Charles Bonnet syndrome. The primary reason why those who are affected do not report the case is believed to be due to stigma of being tagged as insane. It is utterly bothersome for those who have CBS. Nevertheless, the hallucinations would just eventually resolve through time. The length at which people with CBS may continue to suffer from visual hallucinations may range from 12 to 18 months. Some cases reported that the visual hallucinations finally become less frequent on the eighteenth month. This condition primarily affects older people. However, this does not mean that younger ones are spared from the condition. You’ll get to know more about Charles Bonnet syndrome by reading all the rest of this article.


The primary symptom that defines Charles Bonnet syndrome is the presence of visual hallucinations which are oftentimes liliput or involves smaller objects. Nonetheless, the characteristics of the hallucination of those with CBS do not actually resemble those that were experienced by people with psychiatric disorders. In fact, those who were sufferers of CBS have reported that they have pleasant visual hallucinations such that of a flying bird, colorful flowers and other nice stuffs. Generally, people with CBS suffer from vivid visual hallucinations.


A number of underlying pathologies have been directly linked with the development of Charles Bonnet syndrome. However, all the different conditions would eventually come to a common denomination and that is the loss of vision. Charles Bonnet syndrome is actually the result of the brains reaction to the loss of sight. Normally, the moment you see the actual appearance of a certain thing, your brain no longer has to process more images of its own. Nonetheless, when you begin to suffer from a visual loss, your brain is not anymore able to receive further visual inputs and thus this begins to create images that had previously been already there. To date, there’s not actually a specific explanation on how the brain responses to the visual loss in people with CBS. Recent studies aim to arrive at an answer.

One usually begins to suffer from Charles Bonnet syndrome a couple of days or even months following the actual loss of vision. On the other hand, a number of conditions may possibly lead to the loss of sight, including:

  • Cataract
  • Diabetes-related eye conditions
  • Glaucoma
  • Macular degeneration due to old age
  • Other possible eye injuries

The factors which further worsen the visual hallucinations in CBS are listed as follows:


  • Sensory deprivation (such that when a person is isolated)
  • Impaired cognitive abilities
  • Stroke
  • Senescence/Aging
  • Depression
  • Grief (such that in a loss of a loved ones)


When you suspect that you or another person is suffering from Charles Bonnet syndrome, an eye care specialist should immediately be consulted so as further eye examinations can be done. By undergoing a thorough eye examination, any problems which affect the eyes can be immediately treated and this in turn would improve the condition making visual hallucinations less frequent until they eventually resolve.

Doing eye examinations is just one of the possible ways in diagnosing CBS but this isn’t actually the standard mode of diagnosis. Generally, there’s not a specific test for CBS. The latter would just help rule out other possible causes including Alzheimer’s disease and other neurological conditions. When you lost your sight and the other probable causes have already been ruled out then CBS could be a possible diagnosis.


To this very day, there’s not a specific treatment for CBS. All that has to be done is merely to orient the patients of their condition and explain to them that they are not definitely suffering from any mental disorders. It has been found that once the patients have fully understood their condition, the visual hallucinations gradually become less frequent. Generally, any treatment is not necessary for CBS because the visual hallucinations are considered to be just temporary and would eventually just go away on its own.

Though medications are not needed, the use of drugs for Parkinson’s disease, dementia, epilepsy and other neurological disorders have recently been found to improve the condition of patients with CBS. Nevertheless, these medications have also been linked to some serious side-effects. Thence, their use should be strictly supervised by a medical professional. Another finding on the use of the previously mentioned drugs alongside other medications that are usually taken with old age would just exacerbate the visual hallucinations.


It can be utterly terrifying for people to lose their sight and at the same time experience visual hallucinations. Educating the patient of his condition is extremely important so as to eventually recover from CBS. Significant others also play a vital role for the patient’s favorable prognosis. With a strong support system and a positive outlook, the patient would effectively cope up with CBS.

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