Charles Bonnet Syndrome and Visual Hallucinations
Have you ever heard of Charles Bonnet? He was a Swiss naturalist, philosopher, and biologist (1720-1793) who first described the hallucinatory experiences of his 89-year-old grandfather, who was nearly blind in both eyes from cataracts. Charles Bonnet Syndrome is now the term used to describe simple or complex hallucinations in people who have impaired vision.
Symptoms
People who experience these hallucinations know they aren't real. These hallucinations are only visual, and they don't involve any other senses. These images can be simple patterns or more complex, like faces or cartoons. They are more common in people who have retinal conditions that impair their vision, like macular degeneration, but they can occur with any condition that damages the visual pathway. The prevalence of Charles Bonnet Syndrome among adults 65 years and older with significant vision loss is reported to be between 10% and 40%. This condition is probably under reported because people may be worried about being labeled as having a psychiatric condition.
Causes
The causes of these hallucinations are controversial, but the most supported theory is deafferentation, […]