Vision loss and visual hallucinations: the Charles Bonnet syndrome

Around half the people presenting with acquired severe sight loss will at some point experience visual hallucinations. This is a little-known fact, not only amongst patients, but also amongst a significant number of health and eye care professionals. The condition is known as Charles Bonnet syndrome (CBS) and is named after the naturalist who first described this phenomenon in 1759. Although visual hallucinations can be unsettling, current ignorance and lack of information about the condition lead to even greater distress in patients. They may believe that they are suffering from a mental condition, such as dementia, and that they are losing not only their sight, but also their mind. The Royal College of Ophthalmologists1 and the Macular Disease Society (MDS)2 have now initiated a campaign to increase awareness of CBS amongst eye care staff. The many case studies collected by the MDS, such as the following, all tell a similar story.