Charles Bonnet syndrome (CBS) is a condition that causes vivid hallucinations in people who suddenly lose all or part of their vision. It doesn’t affect people who are born with vision problems.
A 2009 study found that anywhere from 10 percent to 38 percent of people with sudden vision impairment have CBS at some point. However, that percentage may be higher because many people are hesitant to report their hallucinations because they worry they’ll be misdiagnosed with a mental illness.
The main symptoms of CBS are visual hallucinations, often shortly after waking up. They might happen on a daily or weekly basis and can last for a few minutes or several hours.
The content of these hallucinations also varies from person to person, but they may include:
- geometric shapes
- costumed people from prior eras
- fantasy-related images, such as dragons
- repeating patterns, such as grids or lines
People have reported having hallucinations in both black and white as well as color. They may also be still or involve movement.
Some people with CBS report seeing the same people and animals over and over again in their hallucinations. This often adds to their concern about being misdiagnosed with mental illness.
When you first start having hallucinations, you may be confused about whether or not they’re real. After confirming with your doctor that they aren’t real, the hallucinations shouldn’t alter your perception of reality. Tell your doctor if you continue to be confused about the reality of your hallucinations. This may indicate an underlying issue.
CBS occurs after losing your eyesight or having visual impairment due to surgery complications or an underlying condition, such as:
- macular degeneration
- severe myopia
- retinitis pigmentosa
- diabetic retinopathy
- optic neuritis
- retinal vein occlusion
- central retinal artery occlusion
- occipital stroke
- temporal arteritis
Researchers aren’t sure about why this happens, but there are several theories. One of the main ones suggests that CBS works similarly to phantom limb pain. Phantom limb pain refers to still feeling pain in a limb that’s been removed. Instead of feeling pain in a limb that’s no longer there, people with CBS may still have visual sensations despite not being able to see.
To diagnose CBS, your doctor will likely give you a physical exam and ask you to describe your hallucinations. They may also order an MRI scan and check for any cognitive or memory-related issues to rule out any other conditions.
There’s no cure for CBS, but several things may help to make the condition more manageable. These include:
- changing your position when you have a hallucination
- moving your eyes or staring right at the hallucination
- using additional lighting in your surroundings
- stimulating your other senses by listening to audiobooks or music
- engaging in social activities to avoid social isolation
- reducing stress and anxiety
Some people also find relief through repetitive transcranial magnetic stimulation. This is a noninvasive process that involves using magnets to stimulate different parts of the brain. It’s often used to treat anxiety and depression.
If you only have partial visual loss, make sure you get regular eye exams and wear any prescribed visual aids to protect your remaining vision.
CBS doesn’t cause any physical complications. However, the stigma surrounding perceived mental illness can lead to feelings of depression and isolation in some people. Joining a support group or regular meeting with a therapist or other mental health professional can help.
CBS is likely more common than we think due to people’s hesitation to tell their doctor about their hallucinations. If you’re having symptoms and worry that your doctor won’t understand, try keeping a log of your hallucinations, including when you have them and what you see. You’ll likely notice a pattern, which is common in hallucinations caused by CBS.
Joining a support group can also help you find doctors who have experience with CBS. For many people with CBS, their hallucinations become less frequent about 12 to 18 months after losing some or all of their vision. For some, they may stop completely.