Horner, or Horner-Bernard, syndrome is a condition that occurs as a result of interruption of sympathetic nerve pathways to the eye, causing a drooping eyelid and constricted pupil, explains Mayo Clinic. Sympathetic nerves control pupil size, heart rate, blood pressure and perspiration. Conditions such as spinal cord injury may cause the problem. Treatment focuses on improving nerve function.
Symptoms of Horner syndrome include dilation of one pupil in dark areas, miosis, drooping of the upper eyelid, elevation of the lower eyelid and anisocoria, which is distinct unequal size of the pupils, explains Mayo Clinic. Children may experience flushing on one side of the face and loss of color in the iris. A person who experiences weakness, loss of muscle control, dizziness, serious headache that occurs unexpectedly or blurred vision requires medical care.
Tumor, stroke, neck trauma and diseases that cause loss of myelin cause nerve malfunction, leading to Horner syndrome, explains Mayo Clinic. Migraines, lung cancer, surgery in the chest cavity, and damage to the aorta or carotid artery may cause the condition as well. Congenital defect of the aorta, tumor of the nervous or hormonal systems, and shoulder or neck injuries that occurs during delivery may cause the problem in children.
A physical and medical examination, imaging techniques and X-rays help diagnose the condition, states Mayo Clinic. Treating the underlying conditions helps restore nerve function, reducing symptoms.