Charles Bonnet Syndrome (CBS)

May 21, 2019
Charles Bonnet syndrome (CBS) is a disease in which vision loss leads to visual hallucinations. The condition is related to psychosis or dementia. Read more about it here!

Of all the human senses, vision might be the most dominant one. We rely on this capacity to perceive environmental images. Therefore, health-related conditions (such as Charles Bonnet syndrome) that affect vision are particularly threatening. For this reason, there’s a huge allocation of resources and efforts dedicated to the prevention, treatment, and cure of these conditions.

You’re probably familiar with many of these eye disorders, such as myopia, astigmatism, and cataracts. On the other hand, there are many other not-so-well-known age-related macular degeneration conditions. In this article, we’re about to discuss Charles Bonnet syndrome, which is quite intriguing.

What’s Charles Bonnet Syndrome (CBS)?

As mentioned above, CBS is a vision disorder. It’s one of the least known and most misunderstood medical conditions out there. It’s characterized by visual hallucinations in patients who’re losing their sight. Thus, it usually manifests in people with vision problems that result from cataracts or glaucoma. It also manifests in patients with damaged primary visual cortexes.

A man pressing his eyes.

The hallucinations Charles Bonnet syndrome causes are very vivid and realistic. However, unlike other disorders characterized by the presence of hallucinations, the patients who suffer from this syndrome know perfectly well that what they’re seeing is an optical illusion. Thus, it’s different from schizophrenia or from hallucinations induced by psychoactive drugs.

Intriguingly, this disorder manifests in otherwise healthy people with visual problems who hallucinate. For this reason, in order to diagnose someone with Charles Bonnet syndrome, it’s necessary to rule out dementia, mental disorders, and intoxication. Also, vision problems tend to afflict older people, which is why CBS is a lot more common in this group.

Characteristics of Hallucinations

The types of hallucinations Charles Bonnet syndrome causes are varied. However, they do have some characteristics in common:

  • A person with CBS is perfectly aware that they’re hallucinating and know that what they’re seeing is a mere optical illusion.
  • Hallucinations mix up with normal perceptions. Instead of totally replacing reality, the images are superimposed on those a person without CBS would normally see.
  • Visual illusions appear and disappear randomly. In this regard, it’s very difficult to find a clear source for the visions or to determine a pattern.
  • People with this condition are often surprised by their hallucinations but seldom worry about what they see.
  • These hallucinations tend to manifest during stressful situations, when there’s a sensory overload, or when there’s a lack of significant stimulation.
  • Illusory images are a lot more vivid than reality. While the rest is blurry, the hallucinations are clear and sharp. This is because Charles Bonnet syndrome only manifests in people with reduced visibility.

Causes and Treatment

Medical science hasn’t yet been able to explain the exact cause of Charles Bonnet syndrome. However, several theories aim to shed some light on this condition.

The most popular hypothesis states that this syndrome manifests when neurons no longer receive the stimulation levels they require. Thus, they become much more sensitive to all external stimuli and, in some cases, may even create their own.

A person holding their head.

There’s currently no cure for Charles Bonnet syndrome. In regard to treatment, physicians simply try to help patients understand that their hallucinations are a normal consequence of their vision loss and that they don’t have any mental health problems. This can be highly reassuring and help the patient better cope with their condition.

After that, the usual approach is to try to solve the vision problem and take measures such as:

  • Changing the lighting conditions in their environment to see if the optical illusions disappear.
  • When in a dimly lit area, switching on more lights or moving to a brighter area.
  • If in a brightly lit area, moving to a dimmer one may help reduce the visions.
  • Shifting the gaze from left to right.
  • Blinking rapidly.
  • Reaching out to touch the vision.
  • Moving around and/or doing a particular task.

Physicians also recommend getting enough hours of sleep at night. Apparently, the hallucinations worsen when people are in need of rest or are under a lot of stress. In most cases, surgery can restore part of a person’s visual acuity and this, in turn, leads to the disappearance of the hallucinations.