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  • Writer's pictureArijit Bhattacharya

Charles Bonnet Syndrome, Where Blind People visualize strange things!!

The name above has already reviled how weird this syndrome is, where a blind person visualizes things That Are Not Real. Charles Bonnet Syndrome is a rare neuro-ophthalmological condition that occurs in people who are either blind or have almost lost their vision. This causes them to have closed-eye hallucinations or visual hallucinations. The hallucination in this case can be a simple pattern, objects, animals, and even people which are only visual and do not involve any auditory or other sensation.

Most of the people who develop Charles Bonnet syndrome, think that it is caused by some mental health problems, but they need to know that it is the loss of eyesight that is responsible for this syndrome; they are not caused by mental health disorders.

Now let us first know why this condition is known as Charles Bonnet Syndrome;

Charles Bonnet was a Swiss philosopher who first described the syndrome in 1760. He described visual hallucinations experienced by his 87-year-old grandfather who was blind to cataracts in both eyes but was visualizing men, women, birds, buildings, and patterns in his surroundings. He was very frightened of this situation and considered it primarily as a psychotic disorder. But after a very detailed and extensive diagnosis, he was found completely fine both physically and mentally though the source of the hallucination remained unknown. 200 years after this documentation, French-Swiss Neurologist Dr. Georges de Morsier named this condition Charles Bonnet Syndrome in Bonnet’s honor.

What Causes Charles Bonnet Syndrome?

It’s strange, right? how can a blind person visualize??

Alright, let me explain…

For a normal person with healthy vision, light enters the eye and is received by the retina and then the retina converts the visual images to visual messages. Those messages are then transferred to the optic lobe of the brain by the optic nerve which is subsequently followed by image analysis. When a person starts losing their vision because of some ophthalmological conditions such as glaucoma, cataract, diabetic retinopathy, eye injury, etc, our brain gets confused because of the interruption of visual image data. Without visual data coming in through the eyes, the brain starts filling up the void spaces (of visual image signal) and makes up fantasy patterns, images, or recalls stored images which cause the person to have hallucinations. These visual hallucinations in a blind person are known as Charles Bonnet Syndrome or CBS.

Symptoms of Charles Bonnet Syndrome:

Visual hallucination or closed-eye hallucination in a blind person is considered the main symptom of CBS. The hallucinations can occur at any time but studies have suggested that the effect of hallucination increases at night or when the person stays in low-light areas. The first few episodes of hallucinations in CBS usually make the person frightened, sometimes complex hallucinations make it very difficult to judge exactly where you are standing and whether you can walk straight or not. Distorted room images, walking people, animals, imaginary creatures, and sudden unknown pattern makes it very strange and disturbing. Another interesting part of these hallucinations is that they are not always colorful, sometimes they can be black and white too. The length of hallucinations can last for seconds and can even stay for hours. Although with episodes becoming shorter and less frequent CBS can improve over time.

Diagnosis of CBS:

Symptoms are the main link to diagnosing CBS as no specific tests exist for this condition. Retina testing is one way to detect the cause of blindness, as without eye blindness or vision loss CBS does not occur. Subsequently, some other tests are done to rule out if any other physiological conditions exist which can cause hallucinations. And if the person finds to have vision loss and visual hallucinations without having a neurological and psychological condition then they are most likely to be diagnosed with CBS.


Till now there is no cure or treatment available for CBS. Normal medications that are used to treat other types of hallucinations do not work in the case of Charles Bonnet Syndrome. Having an idea about CBS and the occurring hallucination is the best thing to manage the disease. Understanding that the hallucinations are normal consequences of vision loss and not a mental health problem, helps reduce the stress and fear. Some techniques and measures can help the person deal with the condition, such as;

  • -Avoiding dark places and increasing the light of the surroundings

  • -Understanding the patterns of hallucinations

  • -Discussing the hallucination

  • -Undergoing psychological counseling to manage stress and fear

  • -Yoga and Meditation, Music and Dance Therapy

Apart from these, some self-care techniques are effective according to the case studies,

  • Moving eyes from left to right and vice versa,

  • Staring at the hallucinations,

  • Looking away from the images,

  • Blinking eyes while having hallucination episodes

Fatigue and stress make CBS worse so taking a good amount of rest and managing stress helps a person to deal with CBS.

In Conclusion, There is nothing to be worried about the condition, usually, it gets fades out with time. It is helpful to know that most people with Charles Bonnet Syndrome don't get scary or threatening hallucinations, it is the sudden occurrence that makes them frightened. Understanding what you are visualizing is not there helps in CBS management.

Also, some support groups are working with people with Charles Bonnet Syndrome. Esme's Umbrella, Royal National Institute Of Blind People, and CBS Foundation are some internationally known awareness campaigns for Charles Bonnet Syndrome, they provide links to information and helpful resources for both patients and healthcare professionals.


  1. American Academy of Ophthalmology. (2019). What Is Charles Bonnet Syndrome? Available at:

  2. Jan, T. and del Castillo, J. (2012). Visual Hallucinations: Charles Bonnet Syndrome. Western Journal of Emergency Medicine, 13(6), pp.544–547. doi:10.5811/westjem.2012.7.12891.

  3. NHS Charles Bonnet syndrome. Available at:

  4. Wikipedia. (2021). Visual release hallucinations. Available at:

  5. (n.d.). Charles Bonnet Syndrome - The American Society of Retina Specialists. Available at:

  6. (n.d.). Charles Bonnet Syndrome Foundation (Australia) - The Condition. Available at:

Write-up and Graphic Designing by Arijit Bhattacharya


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