When the Vision Goes, the Hallucinations Begin

New York Times, September 16, 2004

Susan Kruglinski

A couple of years ago 85 year-old Dorris Stowens saw the monsters from Maurice Sendak's "Where the Wild Things Are" stomping into her bedroom. They soon turned into traditional Indonesian dancers with long brass fingertips, whose furious dance took them from the floor to the walls to the ceiling. Although shocked to witness such a spectacle, Stowens was aware that this was a hallucination, and was certain that this hallucination had something to do with her vision problems due to macular degeneration. "I knew instantly that something was going on between my brain and my eyes," she said.

She knew because ever since she had developed partial vision loss, she had been seeing brownstone walls (colored pink) and early American quilts floating in her blind spots several times each week. When she mentioned the monsters to her support group for the sight disabled at midtown's Jewish Guild for the Blind, she found she was not the only one seeing hallucinations. Another woman has seen faces in the tiles on her bathroom wall. Stowens then confided in a friend whose late husband had macular degeneration. "I said to her, 'Joe never had anything like that?'" she recalls. "And she said, yes, he did have things, but he didn't want to talk about it."

Stowens's monsters and quilts are a result of Charles Bonnet syndrome (CBS), a strange but relatively common disorder that stems directly from vision problems. CBS sufferers see hallucinations within their blindspots but, unlike other illnesses where hallucinations are present, usually have complete insight into the fact that the visions before them are not real. Because the overwhelming majority of people with vision problems are more than 70 years-old, CBS is largely a disorder of the elderly. And because the elderly are more suseptible to cognitive deterioration, which can include hallucinations or delusions, CBS is easily misdiagnosed as a mental illness, or is underreported because sufferers are afraid they will be thought of as crazy.

"It is not a rare disorder," says neurologist V.S. Ramachandran of the University of California at San Diego, who has written about the disorder and seen "dozens and dozens" of patients with CBS. "It's quite common. It's just that people don't want to talk about it when they have it."

There are estimates that ten to fifteen percent of people whose eyesight is worse than 20/60 develop CBS. Any eye disease that may cause blind spots or low vision, such as cataracts, glaucoma, diabetic retinopathy and, most commonly, macular degeneration, can be the source. The hallucinations can range from simple patches of color, grids, and patterns to lifelike images of animals, people, landscapes to phantasms straight out of the most fantastic dreams. Commonly seen are tiny people in ornate costumes, children, and miniature animals. Usually, the hallucinations are brief and nonthreatening, and often CBS sufferers are only minimally distrurbed by the syndrome.

Nancy Johnson, a 72 year-old retired school teacher from San Diego who had her left eye removed because of cancerous tumors, is not bothered by her visual disturbances.

"I see little tiny geometric shapes that all fit together," she says. "Like doodles in the margin of a notebook. It's sort of interesting. It's distracting, but it's not fearful."

"I've rarely seen patients being disturbed by this," says Dr. Ramachandran. "Usually they are amused."

But not always.

"I was terrified," says Stowens of her encounter with the Sendak characters. "I couldn't even speak, my heart was beating so fast."

As in her case, the hallucinations can resemble the frightening psychosis of mental illnesses like schizophrenia. And even when the visions are not threatening, the prospect of having a psychiatric disorder can be frightening enough.

Dr. William O'Connell, a low vision specialist at the Lighthouse in Westchester who has seen scores of patients with CBS, finds that patients are tremendously relieved when told that they are simply suffering from a problem of vision.

"I've had patients tell me, 'I thought I might be getting a brain tumor,'" he says. "Or, 'I thought I might be having a stroke,' or 'I thought I might have Alzheimer's.'"

Because hallucinations usually indicate mental illness, doctors unfamiliar with CBS may misdiagnose the patient. One low vision specialist contacted for this article had never heard of the syndrome.

"A family physician might not be familiar with it because it's mostly a visual problem," says O'Connell. "And unfortunately some opthamologists and optometrists aren't familiar with it because they may not have come across it or done the research when they get patients expressing these types of complaints."

Dr. Peter Rabins, a psychiatrist at Johns Hopkins who has conducted research on CBS, became interested in the syndrome when psychologically healthy patients turned up at his office.

"Individuals would often report to a physcian that they were seeing visions," he says. "So they would get referred to me for evaluation of hallucinations because it was thought that they were psychotic." Journal articles on CBS indicate that some patients have been perscribed antipsychotics for their hallucinations, and in at least one recorded case a patient was sent to a psychiatric hospital.

Many doctors who work with CBS patients say that medication offers no relief. In fact, besides blinking, brightening the light in a room, and other environmental changes that work for some patients, there is little one can do to keep the visions from filling their view from time to time.

This may be because CBS is the consequence of a normal function of the brain responding in an exaggerated way to blindness. Like phantom limbs, where a person vividly perceives a limb that has been amputated, or phantom hearing, where a person may hear music or other sounds when going deaf, the hallucinations of CBS are a direct result of the loss of sensory information that had been constantly streaming into the brain over a lifetime.

In the case of sight, our primary visual cortex is responsible for both the taking in of outside information and the formation of images in memory and imagination. Dr. Ramachandran and others suggest that, because of this dual function, what we consider to be vision may actually be the visual input entering our eyes combining and feeding back with images created in-house -- images of what we have seen before, or what we expect to see. Just as the brain easily fills our natural blind spots with what it guesses should be there, it constantly fills our entire visual field with estimations of what we should be seeing. This is why if you are expecting the person next to you to be wearing a blue shirt, in a quick sideways glance you may actually see that person's red shirt as blue. A more direct gaze allows for more external information to correct the color.

"In a sense, we are all hallucinating all the time, " says Dr. Ramachandran. "What we call normal vision is our selecting the hallucination that best fits reality, to put it bluntly."

So when a person develops a huge blind spot, or scotoma, or loses much of their vision, the brain may continue to fill in the information, but with a much larger margin for error. So large, a person may see famous monsters or Indonesian dancers that are not actually there.

"The most interesting thing to me," says Stowens of her syndrome, "is that this brain of mine keeps telling me things I don't want to know."