When I was a little girl there was an old woman who lived in our small town who was blind. She is the only blind person I have ever personally known. She was not born blind. She became blind as a little girl after an illness.
My limited, childish knowledge of blindness was later complemented with information I gleaned from the “Little House On The Prairie” book series written by Laura Ingalls Wilder. Based on the story of her life, one story she recounts is how her sister became blind. To my child’s mind, a mental image was created of a person who experienced the world around them grow smaller within a tunnel that gradually grew darker and larger until it consumed her. Now I’ve learned that becoming blind is not as simple as that.
Canada’s National Institute for the Blind, after conducting much research, has concluded that many who are experiencing vision loss also experience hallucinations as well as other tricks of the eye. This is called the Charles Bonnet Syndrome, or CBS for short.
Although it seems like this is a new condition, in actuality it probably isn’t. It’s more likely that, in the past, because of the stigma associated with mental illness, many vision loss patients did not share these symptoms with doctors or loved ones out of fear of being labeled “crazy”. However, vision loss hallucinations are probably quite normal and part of the process of the eyes and brain becoming dysfunctional.
Public awareness is important so that people going through vision loss can be reassured that there is nothing wrong with their mental competencies. And, the good news is that, usually, the phase of hallucinations is temporary.
Canada is conducting the largest study of CBS throughout the entire world’s medical communities. Taking part in the study is over 2,500 people who are losing their eyesight due to diabetic related retinopathy, macular degeneration or glaucoma.
One thing that has been determined is that vision loss hallucinations have their own unique characteristics. There are other medical conditions that have hallucinations as a symptom, such as Parkinson’s disease or dementia. But the hallucinations of those patients are distinctly different from the hallucinations experienced by vision loss patients.
One distinction is that, because only vision is affected, not cognitive abilities, a vision loss patient is aware that what they are seeing is a hallucination. Parkinson’s and dementia patients believe that what they are seeing is real. Doctors believe the brains of vision loss patients create hallucinations as a means to compensate for what is lost in the “picture”. The brain is using images in its memory bank to fill in the gaps.
Whereas a Parkinson’s patient or dementia patient may have hallucinations that are not only visual but also believe they are feeling something or hearing or smelling something, CBS patients only have a visual hallucination. Although a CBS hallucination may seem realistic, such as looking out a window at a pastoral scene and the brain inserts a cow into the image, it could just as well insert a dragon that was seen in a book illustration. Usually, however, most CBS patients see patterns and shapes rather than objects.
One interesting commonality among CBS hallucinations is what is called the “little people”. Many CBS patients will have hallucinations of events experienced as little children. These hallucinations will correspondingly include “little people”.
The study determined that as eyesight progressively deteriorates, hallucination frequency will increase. Often, in the early stages, hallucinations may be limited to peripheral vision and indistinct. Many of the images are actually stored memories.
Once patients are reassured by physicians that this is normal and that they are not mentally ill, many accept the hallucinations and tolerate their occurrence. Some find them an annoyance and distraction. These patients often devise methods to disrupt the hallucination such as switching lights on and off or changing their physical movement or rubbing and blinking their eyes. Despite individual reactions, the important thing now is to raise awareness and develop effective means of treating vision loss patients who are experiencing CBS.