Horner syndrome is not preventable, and the cause is due to damage to one of the pathways in the sympathetic nervous system, according to Mayo Clinic. This system regulates several bodily functions including blood pressure, pupil size, perspiration and heart rate.
In most cases, Horner syndrome only affects one side of the face, not both, explains Mayo Clinic. Some of the main symptoms of Horner syndrome include a small pupil, a noticeable difference of pupil size, a delay of dilation in the eye, and a drooping upper eyelid. Other symptoms include an elevation of the lower lid and little or no sweating on the side of the face that the Horner syndrome affects.
If experiencing symptoms of Horner syndrome, it is important for individuals to see a doctor, states Mayo Clinic. A doctor may diagnose Horner syndrome immediately due to the symptoms, but also may conduct other tests. One such test is when a doctor dilates the healthy eye and compares it to the eye showing symptoms of Horner syndrome. A doctor may also order imaging tests to diagnose Horner syndrome including magnetic resonance imaging, computerized tomography and X-ray.
There is no specific treatment for Horner syndrome, claims Mayo Clinic. However, most cases of Horner syndrome disappear when the treatment of the underlying cause of the condition occurs.