|
Charles Bonnet Syndrome
By Lylas G. Mogk, MD and Marja Mogk, PhD, with Carol J. Sussman-Skalka, CSW, MBA
Do you ever see things you know are not there but look real anyway? It's a common side effect among people with vision impairment. While we refer to it as "phantom vision," the technical term is "Charles Bonnet Syndrome." If you've experienced this, rest easy. Your mind is fine. It's your eyes that are playing tricks on you.
What Exactly Is Charles Bonnet Syndrome?
Charles Bonnet, an 18th century Swiss naturalist and philosopher, is credited as the first person to describe the syndrome. Like his grandfather, who had low vision and saw men, women, birds and buildings he knew were not there, Charles experienced similar phantom visions when his own vision deteriorated.
This condition is often described as being similar to phantom limb. People who have a limb amputated may still feel their toes or fingers, or experience itching on an arm that is no longer there. This happens because the limb's nerves are still active and sending signals to the brain, which the brain interprets as sensations from the missing limb. Similarly, when retinal cells become impaired and are no longer able to receive and relay visual images to the brain, the visual system begins firing off images on its own.
Often, these images are not related at all to a person's life. In their book Macular Degeneration: The Complete Guide to Saving and Maximizing Your Sight, authors Lylas G. Mogk MD and Marja Mogk, PhD, recount the story of Sam, who has macular degeneration. Sam said, "I see little monkeys with red hats and blue coats playing in the front yard." Sam had no doubt that the monkeys he saw were not real ones. As a result, he wasn't concerned about his mind. However, he was worried about what others would think, so he kept it to himself.
How Common Is It?
Studies show that Charles Bonnet Syndrome affects between 10 and 40 percent of people with low vision. Research suggests that it is more likely to appear if you have visual acuity between 20/120 and 20/400. If your vision falls within these parameters, your eyes still have a great deal of power, even though they aren't receiving or sending as many images as previously. As a result, your eyes may be providing additional images of their own.
There is no way to predict whether you will see images and, if you do, how frequently they will occur or how long they will last. You may never experience Charles Bonnet Syndrome, you may have it for only a few months, or you may have it for years. You may see images every day, a few times a week or several times a month.
Are You Sure This Is Not a Psychiatric Problem?
Yes! Charles Bonnet Syndrome is no more than a side effect of vision loss. Mogk and Mogk give the six criteria for images typical of Charles Bonnet Syndrome:
"They occur when you are fully conscious and wide awake, often during broad daylight.
They do not deceive you; you are aware that they are not real.
They occur in combination with normal perception. For example, you may see a sidewalk clearly but find it covered with dots, flowers, or faces.
They are exclusively visual and do not appear in combination with any sounds or bizarre sensations.
They appear and disappear without obvious cause.
They are amusing or annoying but not grotesque."
Mogk and Mogk go on to state, "Since ophthalmology has paid so little attention to Charles Bonnet Syndrome, many doctors don't realize how common it really is, and some may not be familiar with it at all."
What Do People Actually See?
Patients, according to Mogk and Mogk, "have reported seeing cartoon characters, flowers in the bathroom sink, hands rubbing each other, waterfalls and mountains, tigers, maple trees in vibrant autumn foliage, yellow polka dots, row houses, a dinner party and brightly colored balloons. Many people see faces or life-size figures that they've never seen before. One of the most remarkable qualities of these figures is that they almost always wear pleasant expressions and often make eye contact with the viewer.
"Usually the same image or set of images reappears to each person, sometimes in the same places or at the same time of day. Sam's monkeys usually materialized around sunset, cavorting across the lawn or around the big blue easy chair by the fireplace. They stayed for 10 or 20 minutes several times a week for two years and then began to appear less frequently."
Is Charles Bonnet Syndrome Treatable?
A majority of people do not find their phantom vision disturbing, probably because the images they see are amusing, pleasing or entertaining. You may want to discuss your phantom vision with your doctor, particularly if you feel bothered or distressed by your experiences. While there does not seem to be any specific medications that work for everyone, many people find that learning more about the condition helps to reassure them.
This article is based on, and includes quotes from, a chapter in Macular Degeneration: The Complete Guide to Saving and Maximizing Your Sight, written by Lylas G. Mogk, MD, and Marja Mogk, PhD, published by The Ballantine Publishing Group (2003).