Horner syndrome is a combination of signs and symptoms caused by the disruption of a nerve pathway from the brain to the face and eye on one side of the body.
Typically, Horner syndrome results in a decreased pupil size, a drooping eyelid and decreased sweating on the affected side of your face.
Horner syndrome is the result of another medical problem, such as a stroke, tumor or spinal cord injury. In some cases, no underlying cause can be found. There's no specific treatment for Horner syndrome, but treatment for the underlying cause may restore normal nerve function.
Horner syndrome is also known as Horner-Bernard syndrome or oculosympathetic palsy.