Any eye condition, including age-related macular degeneration (AMD) that results in vision loss can lead to a person experiencing visual hallucinations. Wet age-related macular degeneration causes significant vision loss due to the leaking of plasma and blood from abnormal blood vessels in the back of the eye, resulting in permanent macular damage.
Visual hallucinations that appear as a result of vision loss are also known as Charles Bonnet syndrome (CBS), and are an infrequent, yet sometimes disabling, symptom of wet AMD that occurs in some patients. These hallucinations, which result from vision loss and not due to mental illness, can be highly disconcerting and even frightening when they first appear.
These hallucinations have no known cure or single treatment. However, by understanding what causes them, you’ll be able to reduce your anxiety when they occur — and establish techniques to get through them with minimal discomfort.
What is Charles Bonnet Syndrome?
Charles Bonnet syndrome (CBS) affects some patients with low vision caused by a variety of eye diseases. Patterns, as well as more complex pictures such as people, animals, flowers, and buildings, can appear in these hallucinations.
If you lose vision from any eye condition, including age-related macular degeneration, glaucoma, or diabetic retinopathy, the eyes no longer send signals to the brain as before. Without visual signals arriving at the brain, the brain then fills the void by recalling images from memory, resulting in the visual hallucinations of CBS.
CBS is named after Charles Bonnet, an 18th-century Swiss scientist who first identified this condition in his grandfather and then developed it himself.
What Do Visual Hallucinations Look Like?
Charles Bonnet hallucinations may appear as simple unformed flashes of light, colors or shapes.
However, many people envision more complex structures, such as geometrical grids and lattices.
Landscaped gardens or views, animals, people and a procession of small costumed characters wearing hats have also been reported by CBS patients, according to the Macular Society. The hallucinations are frequently depicted in greater detail than they would if they were real.
Some people find their hallucinations enjoyable. Others find them an unwelcome inconvenience, especially if they temporarily obstruct vision.
When Do Visual Hallucinations Occur?
CBS hallucinations come and go without warning, typically spanning months or years, with no apparent reason and no connection to cognitive or psychiatric disease.
The syndrome’s prevalence in patients with visual impairment varies from 10% to 15%, but it can can also affect patients with other macular diseases, ocular conditions including glaucoma, and stroke.
CBS is more frequent in people over the age of 80, but it can affect anyone at any age. CBS does not necessarily indicate that an individual's vision is deteriorating, and people can have visual hallucinations even if they just have minor vision loss or small blind spots.
What Causes CBS?
Exactly what causes visual hallucinations is unknown, but researchers believe that deafferentation (the interruption or destruction of nerve cells) leads to the loss of signals from the eye to the brain. MRI investigations show that these visual signals ordinarily inhibit some nerve activity in the brain and when the signals are missing, there is more spontaneous nerve activity, which is perceived as hallucinations.
How to Manage Visual Hallucinations
Eye movements appear to reduce the severity and duration of hallucinations. Even if individuals have limited remaining vision, eye movements engage visual areas of the brain in people with macular degeneration. Certain types of hallucinations, notably patterns and colors, may be stopped by these motions.
Dr. Dominic ffytche at King’s College, London, recommends that patients consciously move their eyes when experiencing a hallucination.
Try the following exercise:
- Imagine two locations on a wall in front of you that are about 3 feet apart to the left and right. For 15–30 seconds, stand approximately 3.5 feet away and glance from one place to the other once every second or faster. When looking left and right, don't move your head and keep your eyes open. Allow yourself a brief break.
- Try repeating the exercise if your hallucinations are still there.
The technique is unlikely to work if the hallucinations have not stopped after four or five attempts. However, you might want to try again later.
Other ways to stop a hallucination:
- Look away from the image towards an object on the side of your vision or shut your eyes
- Turn on the lights in the room or, if you're in a brightly lighted place, go somewhere darker.
- Get up and engage in an activity.
If you have wet AMD and are experiencing visual hallucinations, contact Kissel Eye Care Low Vision Center. We can help you manage your AMD.
Kissel Eye Care Low Vision Center serves patients from Lititz, Lancaster County, Elizabeth Township, and East Petersburg, Pennsylvania and surrounding communities.
- A: Yes. Individuals with vision loss who are over 80, live in isolation or in dark environments are at a higher risk of experiencing visual hallucinations.
- A: Other disorders that might cause visual hallucinations include psychiatric diseases and neurologic conditions like Parkinson's disease and Alzheimer's disease. Visual hallucinations can be also caused by a variety of prescription and illegal substances, as well as withdrawal from drugs or alcohol. Tell your eye doctor if you are experiencing hallucinations.