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Charles Bonnet Syndrome

The title of this month's column sounds like some rare chromosomal abnormality, but in fact it is a far more common phenomenon than one may imagine.

Many individuals with acquired vision loss, when questioned thoroughly regarding their functional vision, will report seeing colors, shapes, even people in the area of their visual field that is affected. For example, an individual with macular degeneration and a central blind spot may 'see' flowers or roadmaps or other images floating in that area that once held the most acute vision. Those with central vision loss are certainly not alone in their visual experience. Individuals with total acquired vision loss may also experience this, and images may not always be so ill defined as flowers or maps. One gentleman in our clinic, blind from end stage glaucoma, reported seeing a lovely African lady wearing a bandana and watching him from time to time. He never met a woman with this description, and has no idea where she came from.

Once practitioners learn to ask about these 'pseudohallucinations,' we learn that a great majority of individuals with acquired vision loss experience these, but are often afraid to speak of it, fearing ridicule or mental illness. Once the barriers of communication and understanding are lowered, individuals with acquired vision loss become more open to discussing their images. A recent article in Journal of Vision Impairment and Blindness suggests that these images result from 'noise' in the visual cortex similar to the patterns that occur during sleep. The images, as in our dreams, may represent fears or experiences or other subtle emotions lingering beneath the subconscious. Perhaps a road map represents a feeling of being lost, so common in experiencing the stages of grief associated with vision changes. The authors of this article go on to suggest that discussing these pseudohallucinations, or Charles Bonnet Syndrome, is helpful both in working through the psychosocial implications of vision deficits as well as boosting the individual's self confidence in that they are assured that this is a normal phenomenon and not a product of old age or disease.

J. Hensil