Rena Tonkin was surprised to see grapes dangling from trees as she and her daughter drove back to Portland from the Oregon Coast.
That unusual sight was Tonkin’s first experience with Charles Bonnet Syndrome (CBS), a common condition that causes “phantom” visions in people with reduced or poor vision. It is named after an 18th century Swiss philosopher and writer who described how his blind grandfather reported seeing detailed and fanciful patterns, buildings and people.
Tonkin, who has lost eyesight from age-related macular degeneration (AMD), continues to have visual hallucinations, but is no longer frightened by them. “I now see children wearing plaid clothing jumping around in front of me,” she says, joking that her long career in design may have something to do with the images.
Hallucinations from CBS usually pop up from memory and may be the brain’s way of compensating for the loss of visual input it gets from the eye’s photoreceptor cells, explains Thomas Hwang, M.D., a retina specialist at OHSU Casey Eye Institute. Studies show that the syndrome is more prevalent in older people and may affect about 10 to 15 percent of those with low vision. People with CBS may have frequent visual hallucinations at first, which can range from simple repeated patterns to complex images of landscapes, people dressed in elaborate costumes or animals. Over time, they usually taper off and may eventually stop.
Although CBS is physically harmless, it can be emotionally wearing. Sufferers may be reluctant to tell their doctor or family about their visions because they are embarrassed or fear it is a sign of a mental health problem or dementia. There is no cure for CBS, but talking about it may help, says Hwang.
“I really feel that Charles Bonnet needs to be talked about, especially to anyone experiencing rapid vision loss. Seeing things just adds to the anxiety of losing eyesight,” says Marja Byers, executive director of Blindskills, a Salem, Ore. organization that serves visually impaired and blind people. Byers says she experienced CBS soon after eye surgery, when she saw bushes, tall grasses and a weeping willow while at a restaurant. “I’m really glad I knew what it was before it happened. It would have been absolutely terrifying,” she says.
When members of Blindskills’ support group bring up CBS at meetings, “others are suddenly confessing that they also are experiencing visions. It’s very common but people don’t want to say anything,” says Byers.
Tonkin’s daughter Cheryl Tonkin also believes that family members need to be clued in about CBS. “It’s important for caregivers and family to know what it is so they can reassure their loved ones and realize it’s not a serious cognitive issue,” she says.
Coping with Charles Bonnet Syndrome
You may find it helpful try one of their suggestions for making the images fade or disappear:
- Changing your environment may help. Turn on the TV or radio, move around or make the room brighter with lighting or by opening curtains.
- Look directly at the image, move your eyes or blink rapidly.
- Reach out and try to touch the hallucination.