I have read several articles about Charles Bonnet Syndrome over the years and each of them has left me very intrigued with how little we know about the human mind.
What exactly is Charles Bonnet Syndrome?
Charles Bonnet syndrome (or CBS for short) is a term used to describe the situation when people with sight problems start to experience complex visual hallucinations.
Charles Bonnet was a naturalist from Switzerland who became concerned but also intrigued when his grandfather, Charles Lullin, began to experience visions. Lullin, who was 89 years old at the time, reported seeing people, buildings, and animals. All of which, were invisible to everyone but him.
Even more interestingly, the images were strikingly clear and seemed to materialize spontaneously in his surroundings even though he could see very little at this age due to cataracts.
People with CBS see very realistic images in their surroundings that are not real. However, differing from those who suffer mental health conditions, for the most part, those with CBS are aware that these hallucinations, although vivid, are not real.
Lullin was completely aware that the things that appeared so clearly in his vision were not real and Charles Bonnet began to record these curious visions. Over time, medical professionals began to refer the the syndrome by Bonnet's name.
What sorts of hallucinations are we talking here?
Well, it does vary from individual to individual, but there are quite a few similarities reported from those with the syndrome. And they can mostly be separated into two categories.
First, there are those who see patterns or lines. These can range from very simple to complicated such as mosaic, tiles, or brickwork.
Secondly, there are more complicated hallucinations that can be anything from something as commonplace as a wine bottle on a counter to entire groups of people. Many sufferers have reported "lilliput hallucinations" or or hallucinations in which the characters or objects are smaller than usual.
Both types can be seen in either black and white or color, depending on the individual. And although they can be startling, these hallucinations are generally pleasant.
So who suffers from Charles Bonnet Syndrome again?
Most of those afflicted with the syndrome are in the early stages of vision loss. The most common culprit is Macular Degeneration. Cataracts and Glaucoma have been known to be related to CBS as well. Interestingly, the likelihood of cases increases in people who have limited social interaction, such as those who live alone.
What causes Charles Bonnet Syndrome?
While the cause of CBS is not known at this time, the most commonly accepted theory suggests that the syndrome is the brain doing what it can to compensate for a lack of visual stimuli.
This theory is not so outrageous considering that we know that every human brain is capable of dealing with partial blindness. Every human eye has a blind spot in it's field of vision where the optic nerve passes through the retina. The visual cortex in our brain compensates for this small spot and automatically fills it in with what should be there based on the surrounding detail.
Since the spots in each eye do not overlap, the brain is also capable of cross referencing what each eye sees when they are both active.
Why does the brain cause these hallucinations?
Some have suggested that these visions happen for the same reasons that we dream at night. Clearly, our brains are lacking visual stimulation while we are sleeping so it's not unreasonable to conclude that both dreams and CBS hallucinations may be a result of the same circumstances. The visual cortex senses a lack of visual stimulation and gratifies itself using imagery stored in both our imaginations and our memories.
Any other theories?
Well, now that you ask... There are those who believe the hallucinations have nothing to do with understimulated brain cells. But rather, they are real images from an alternate reality parallel to the one we live in. Those who believe in this theory suggest that people cannot normally see these images around us due to the vast amount of visual data from our own world.
It is also suggested that in these parallel realities it is entirely acceptable to accredit preposterous ideas and disregard all available evidence.
