Charles Bonnet Syndrome

Charles Bonnet Syndrome is a condition that occurs in patients with significant loss of vision in one or both eyes. When the brain does not receive visual images from the eye, it may try and “fill the void” with visual hallucinations (seeing things that really are not there). The hallucinations are quite vivid and realistic, and may consist of people, objects, landscapes, or geometric shapes or lines. The images of people are generally strangers, not persons with a known identity. The condition is analogous to situations in which someone has lost an arm or leg and experiences “phantom limb pain.”

Charles Bonnet Syndrome typically only occurs with severe loss of vision, as may be seen in end stage macular degeneration or glaucoma. Another example is a patient who lost all the vision in the left eye after a hemorrhage, who began “seeing people” on his left side while taking a walk. Once he turns and looks with his right eye the image disappears.

While the condition is not dangerous, the hallucinations can be very unsettling and frustrating for the patient. Other causes of hallucinations, such as medication side effects, infections, or neurologic diseases should be excluded. Typically, blinking and/or quickly moving your head and eyes from side to side will make the hallucinations go away.  Although there is no treatment or cure for Charles Bonnet Syndrome, just reassuring the patient that the hallucinations are not a sign of a mental illness or neurologic condition is generally very helpful.

Concept illustration of Charles Bonnet Syndrome