Charles Bonnet Syndrome — A Public Service Announcement

When Charles Bonet Comes Calling: A Public Service Announcement


Here’s an experiment. Close your eyes and cover them until you see a blank screen. Your eyes may flicker a while then settle down. For some who are losing vision, sometimes this blank screen turns into a picture show. Our brains switch modes when our sight changes. We have a saying, “Charles Bonnet came calling!”


The real Charles Bonnet was a natural scientist and philosopher in the 18th century. Bonnet studied his grandfather’s descriptions of animals and objects he “saw” despite dense cataracts. The name Charles Bonnet Syndrome (CBS) stuck for two centuries, joining the medical vernacular in the 1980s.


However, few people losing vision learn about the condition, or believe what they read — until CBS visits them. It’s hard to imagine what our brains are doing unless they “show their work”. That’s the theory behind CBS. The brain’s vision processing area is busy tracking movement in the external world then informing the rest of our brains for action and storage. When fewer visual signals flow through the optic nerve, the visual activity keeps going, looking for something to work on. Other parts of the brain supply memories and patterns that cause visual fantasies. Another description is that CBS is like “phantom limb”, only more entertaining!


A person with CBS now has a little secret about those visual illusions. Does one tell? Do you fear that you’re on the dementia or mental illness trail? For most of us, the condition is transient, internal, and pleasurable. Some suffer if their illusions interact with their external world, like seeing chorus lines of dancing figures, extra people, snakes, etc. Misdiagnosis threatens as most mental health practitioners don’t have CBS on their symptom and causes lists. Reports tell of CBS leading patients through psychiatric wards and useless prescriptions. Eye doctors have trouble finding the right time to talk about something they haven’t experienced and cannot treat. CBS is an orphaned condition, yet rational and natural for enlightened Vision Losers.


Are you ready to hear about my internal visual world?


One evening, relaxing on my deck, three faces swirled into my line of sight. Having read about CBS, I welcomed my visitors. But, they weren’t what I expected. Each resembled the bust of a statue, gray, molded, with vague facial features, hairlines, silent, just there. But, none was identifiable in my memory gallery of real human faces. These abstract images hung around a while, then swirled back into darkness. I felt no other sensation, knew I was watching an illusion, and soon became accustomed to their coming and going.


A more emotional person might have dubbed them spiritual guides, reincarnations, aliens, or calls to artistic pursuits. I was fine with the simple CBS explanation, not that I told anybody outside my online vision group. Later in this first phase, the heads dissolved into masks with big eyes and huge teeth that slowly melted away. By then I was identifying persons in real life by stature, voice, and guessing rather than facial features. For me, These abstract images were simply illusions welcomed back into my inner world.


Next came another common CBS format, something graphical. I often saw a calendar like chart with one date bold and standing out, frustratingly unreadable. Sometimes I saw a page of justified text, blurred, with a caption, also illegible. This image brought a reverie back to my early career fifteen minutes of fame for finding embarrassing errors in a text justification program published by a famous, elegant European computer scientist. Our dinner in Denmark is another story.


The graphical images were annoying when they blocked other vision and disrupted my thoughts. Blinking and rapid horizontal eye movement usually dispelled the graphics.


All my images until then had been colorless. Months passed,with more vision loss, then appeared, and reappeared, a single realistic picture. A bright yellow tall notepad filled the image, with two fleshy pink hands writing as if adding a note. OMG, this must mean something I’ve forgotten to complete my life!


So, here’s my Public Service Announcement, offered to vision support groups and occasional tweets:

“Vision loss can lead to visual illusions that are harmless, incurable,and dissipate over time. Look up the condition called Charles Bonnet Syndrome, and enjoy its visits.”

Notes:


  • Oliver Sacks T.E.D talk and “Hallucinations book by Oliver Sacks.
  • Online groups Macular Degeneration Support and Vision Aware warn and reassure people with macular degeneration.
  • Wikipedia documents the life of Charles Bonnet and “Visual Release Hallucinations” aka “Charles Bonnet Syndrome”.
  • Margaret Atwood in her”Stone Mattress” stories describes a bad case.
  • The British RNIB offers hotlines and counseling.



      This article was ritten for

      Author: slger

      Susan L. Gerhart (slger) is a retired computer scientist. Her professional specialities included software engineering research, technology transfer management, and computer science education, see SLGer's Research Autobiography. Susan is active in a lifelong learning institute (OLLI) at Yavapai College in Prescott Arizona. She has facilitated courses on podcasts, Twitter, the Singularity, and climate fiction. "As Your World Changes" blog describes her journey with vision loss into the spectacular world of assistive technology and the frustrating practices of accessibility. She writes with the NVDA screen reader, reads books from Bookshare on a BookSense, and listens to podcasts on an iPhone. slger123 on Twitter records her favorite articles and occasional comments on life and politics. Creative writing courses led her to undertake "A Chip On Her Shoulder", a novel asking the questions: "how did we get into the privacy mess of modern social media?" and "Are we now just 'packets of data formerly known as people'?" She's enduring the 2020 Pandemic era and autocracy challenge by analyzing changes in progress, promising, and unknown. Times sure are changing! Contact: slger123 at gmail.com

One thought on “Charles Bonnet Syndrome — A Public Service Announcement”

  1. presentation at
    [audio src="http://www.mdsupport.org/nsg/CBS-encore.mp3" /]

    explaining the hallucination and how people with macular degeneration experience it during vision loss.

    Thanks to Dan Roberts, Director, MDSupport.org

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