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Eyes - Charles Bonnet syndrome

Charles Bonnet syndrome refers to the visual hallucinations caused by the brain’s adjustment to significant vision loss. It occurs most often among the elderly who are more likely than any other age group to have eye conditions that affect sight, such as age-related macular degeneration.

Charles Bonnet syndrome refers to the visual hallucinations caused by the brain’s adjustment to significant. It occurs most often among the elderly who are more likely than any other age group to have eye conditions that affect sight, such as age-related macular degeneration. Estimates vary, but it is thought that about one person in every two with vision loss may experience hallucinations, which means Charles Bonnet syndrome is very common.

Despite this, most people are not aware of this condition. Research suggests that many people who suffer from Charles Bonnet syndrome do not consult their doctor out of fear and embarrassment, as hallucinations are associated with mental illness. In most cases, the hallucinations go away as the brain adapts.

The underlying mechanism of Charles Bonnet syndrome is not understood. Doctors know that vision loss triggers the visual hallucinations. It is not clear how the stores visual information, but we know that visual information from the eyes stops the brain from creating its own images.

Perhaps the loss of visual information from the eyes allows the brain to ‘play’ with its stored picture library. The signs and symptoms of Charles Bonnet syndrome include:

  • A realization that the hallucinations aren’t real. Generally
  • the hallucinations tend to occur when the person is alone
  • in a familiar environment for example when lying awake in bed

The two types of visual hallucination most common to Charles Bonnet syndrome include:

  • Simple – such as patterns lines for example
  • the person may see brickwork images
  • netting or mosaics Complicated – such as seeing people
  • landscapes or places. Complicated hallucinations are more likely to occur in people with severe vision loss

The features of hallucinations can vary widely from one episode to the next and from one person to the next.

For example, the images may be: different every time, or a person may see the same items in every hallucination. A person with Charles Bonnet syndrome has no control over their hallucinations. They may cause issues in their everyday life because: The hallucinations overlay images of the real world, so the person may have trouble negotiating everyday tasks, such as walking through an unfamiliar environment.

The person may not know at first whether the image is real or imagined, which can be frightening if they are seeing, for example, a stranger in the house. Seeing things that aren’t there is distressing, even if the images are pleasant. The person may fear they are going mad or exhibiting signs of dementia.

Visual hallucinations may have causes other than Charles Bonnet syndrome, including: that includes the hormone erythropoietin. Diagnosis of Charles Bonnet syndrome may include:

  • medical tests to rule out other causes of visual hallucinations. In most cases
  • Charles Bonnet syndrome resolves itself after about 12 to 18 months without treatment

It is a good idea to find out everything you can about Charles Bonnet syndrome. Understanding the condition can help to reduce feelings of anxiety and helplessness. Sometimes the hallucinations don’t go away, but there is no medical cure.

Depending on the severity of the condition, treatment may include: Medical advice – talking it over with a doctor or counselor can be helpful.

Vision therapy – low-vision rehabilitation may help to ease symptoms#

Moving your eyes – some people report that the hallucinations dissipate if they move their gaze from side to side or up and down.

Changing the variables – to ‘turn off’ the hallucination, you could try altering the environment or setting that you are in.

For example: if it’s dark, turn on the light, or if you’re standing up, sit down.

If your eyes are open, shut them, or if you’re in one room, go to another room.

Causes of Charles Bonnet syndrome brain Symptoms of Charles Bonnet syndrome Significant vision loss Visual hallucinations No control over the hallucinations Types of hallucinations in Charles Bonnet syndrome Features of Charles Bonnet hallucinations color, or black and white static like a photograph, or moving like an event in real life life-sized, or reduced in size realistic (such as animals from the real world), or fantastic (such as mythological monsters) brief (they continue for a few minutes), or lengthy (they persist for a few hours) enjoyable like a pleasant dream, or frightening like a nightmare meaningless and random, or featuring familiar people or familiar places Complications of Charles Bonnet syndrome Other causes of visual hallucinations dementia some forms of mental illness stroke estrogen replacement therapy parkinson’s disease psychotic drugs such as cannabis blindness in one side of the visual field (hemianopia) pituitary tumor short-term after-effects of cataract surgery kidney dialysis Diagnosis of Charles Bonnet syndrome your medical history a physical examination an eye examination Treatment for Charles Bonnet syndrome

Where to get help#

Key Points#

  • Charles Bonnet syndrome refers to the visual hallucinations caused by the brain’s adjustment to significant
  • signs and symptoms of Charles Bonnet syndrome include: A realization that the hallucinations aren’t real
  • Diagnosis of Charles Bonnet syndrome may include: medical tests to rule out other causes of visual hallucinations
  • In most cases, Charles Bonnet syndrome resolves itself after about 12 to 18 months without treatment
  • Vision therapy – low-vision rehabilitation may help to ease symptoms

Sources & further reading

For evidence-based global guidance on this topic, consult authoritative public-health bodies such as the World Health Organization (WHO), CDC, NHS, and ECDC.

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