What Is Charles Bonnet Syndrome?

Medically Reviewed by Mahammad Juber, MD on April 10, 2022
Written by Victoria Hamilton
4 min read

When someone is losing or has lost their ability to see, they may experience Charles Bonnet syndrome. While this fairly common condition isn’t necessarily dangerous, it can cause distress and anxiety.

As your vision deteriorates, you may start to hallucinate or see things that aren’t really there. These hallucinations can vary greatly and may include anything from subtle patterns to vivid images, events, places, or people. Such visions are limited to your sight and won’t stimulate any other senses. If you have Charles Bonnet syndrome, you’ll know that the visions aren’t real no matter how lifelike they seem.

This condition affects those who have lost or are losing their eyesight, and is more likely to happen in those with vision loss in both eyes. Charles Bonnet syndrome is linked to macular degeneration — around half of all individuals with this eye condition experience hallucinations. You can get Charles Bonnet syndrome at any age, but it’s most common in older people since aging is more linked to vision loss.

Charles Bonnet syndrome symptoms that differentiate it from mental health conditions, include:

  • Significant loss in vision
  • Patterned or image-based hallucinations
  • Lack of control over the hallucinations
  • A knowledge that the hallucinations are not reality

Charles Bonnet syndrome hallucinations usually fall into one of two categories: patterns and detailed images. The two kinds of visions are often referred to as simple and complicated. Simple hallucinations involve patterns, and complicated hallucinations are image-based.

With simple hallucinations, you’ll see repeated patterns that might look like bright and colorful lines, shapes, or grids. These patterns will overlay your vision, meaning you’ll see them on top of the other things you typically see.

If your hallucinations consist of images, you might see people, animals, insects, places, or any variety of things. You likely won’t see people that you know personally or events that you’ve experienced firsthand.

The first hallucination may be startling, but once you understand what’s happening — regardless of what hallucinations you see — they shouldn’t be scary or unpleasant after your first time. Hallucinations can happen at any time, appear without warning, and last anywhere from a few minutes to a few hours.

Charles Bonnet syndrome causes aren’t known for sure, but one theory suggests that these hallucinations happen because of the brain’s reaction to suddenly losing the ability to see. The brain receives less information as vision fades, and these hallucinations could be the brain’s efforts to fill in the gaps.

There is no known cure for Charles Bonnet syndrome. It can be helpful just to know that hallucinations normally happen when you lose your vision and that it isn’t necessarily a sign of a mental health condition. There are no specific medications available for people with Charles Bonnet syndrome. However, some medications meant to treat epilepsy, Parkinson’s disease, and dementia have helped reduce hallucinations in some people, but they can have serious side effects.

You can try taking certain self-help measures when you experience hallucinations, including:

  • Change the lighting where you are. If you’re in a dark area, make it brighter — and vice versa — to see if what you’re seeing disappears.
  • Look quickly to the left and then the right. Do this 15 times without moving your head. Pause, then repeat a few more times.
  • Look straight at the hallucination or reach out to touch it and blink quickly for a few seconds.
  • Change what you’re doing; try moving around or performing a new task.
  • Prioritize rest. Hallucinations can get worse if you’re overtired or stressed out.

When diagnosing Charles Bonnet syndrome, your healthcare provider will focus on your medical history and try to eliminate other possible sources for your hallucinations. There isn’t a test dedicated to diagnosing Charles Bonnet syndrome, but they may ask you questions about:

  • Medications you take
  • Mental health conditions you may have
  • Other brain conditions you may have

It’s likely that, if you have visual hallucinations and deteriorating vision without any other conditions, you will be diagnosed with Charles Bonnet syndrome.

Although there aren’t any health-related complications that come with Charles Bonnet syndrome, you may run into certain issues as you go about your daily activities. Challenges can include:

  • Difficulty carrying out everyday tasks. Your hallucinations can make it even more difficult to see, and you could have trouble depending on how much of your sight you’ve lost and how complicated the vision is.
  • Initial fear of the hallucinations. When you first start to experience Charles Bonnet syndrome, you might not know if what you’re seeing is real or fake. This could cause unnecessary anxiety until you get used to your condition.
  • Worried feelings. Similarly, you may be concerned that you’re showing signs of a more serious issue until you learn about Charles Bonnet syndrome.

If you're losing your vision and think you might have Charles Bonnet syndrome, get in touch with your healthcare provider. They, along with an optometrist and possibly an ophthalmologist, will diagnose your condition and help you learn to live with it.

Remember, what you’re seeing isn’t real. Don’t act on what you see and don’t feel ashamed to talk about what you experience. Consider talking to a therapist, loved one, or Charles Bonnet syndrome support group for validation and to avoid isolation.