Updated 13 April 2015

Answer: What's your diagnosis? – Case 4

Mrs T, an eccentric former fashion designer suffers from a rather strange condition called Charles Bonnet Syndrome.


This week we followed Mrs T, an eccentric fashion designer, who presented to her doctor with a history of seeing “odd” things.

Read the full case study here.

Mrs T suffers from a relatively rare condition called Charles Bonnet Syndrome (CBS).  It was first described in the late 1700s by Charles Bonnet, a naturalist and philosophical writer from Switzerland.  It only became a well-known condition after it was noted by the English speaking scientific community in the 1980s.

The Charles Bonnet Syndrome foundation formally describes the condition as “the occurrence of phantom visions in people living with some form of eye disease who are otherwise cognitively and psychologically healthy. These phantom images co-exist with one's usual perception. That is, vision-impaired people who experience phantom images know that what they are ‘seeing’ is not really there. These phantom images can include geometric patterns, faces, figures, animals, flowers, buildings and even full landscapes.”

In Mrs T’s case, she might have a condition called age-related macular degeneration which would explain her deteriorating vision over the past two years.

While there are no precise diagnostic criteria for CBS, it is generally accepted that in spite of vision impairment, the patient is fully aware that what they’re seeing is not real. (The person understands that the images are not really there. This is in contradiction with delusions or hallucinations of a psychiatric nature where the person believes that what they see is real.)

CBS might be more common than believed, but unfortunately the condition is not well described.

NOTE: Health24's on-site GP Dr Owen Wiese will reveal new cases on Thursdays and we'll post the answer with the story on Mondays, or you can find out via the Daily Tip – sign up here.

Previously on What's Your Diagnosis

What's your diagnosis? – Case 1: vomiting and weight loss
What's your diagnosis? – Case 2: eye pain
What's your diagnosis Case 3: strange behaviour and a bullet in the back?

Image: Hallucinations, delirium in EKW tunnel from Shutterstock

Dr. Owen J. Wiese is Health24's resident doctor. After graduating from Stellenbosch University with additional qualifications in biochemistry and physiology he developed a keen interest in providing medical information through the media.


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