Charles Bonnet syndrome is a condition that causes visual hallucinations in people with vision loss. It is named after the 17th century Swiss naturalist Charles Bonnet, who was the first to document this phenomenon. People with Charles Bonnet syndrome will experience complex visual hallucinations including detailed shapes, animals and even people, as well as less specific forms of movement or flashes of light. The cause is not yet known and the condition does not cause any physical or emotional harm to those exhibiting symptoms, but can be distressing for some individuals. Treatment is strictly supportive and often focuses on providing reassurance so that patients can accept their hallucinations and minimize distress.