Horner’s syndrome refers to a rare condition with signs and symptoms caused by a disrupted nerve pathway that runs from the brain to the eye and face. The eye is the most affected, and these signs and symptoms usually affect only one side of the face. These nerves perform involuntary functions like perspiration and constriction/dilation of the pupils. The signs and symptoms related to Horner’s syndrome typically do not affect a person’s vision or health. However, they can be an indication that the affected person may be having serious underlying health problems. 


Also Known As

  • Oculosympathetic palsy
  • Horner-Bernard syndrome



The three paths used for travel by the nerves to the face and eyes constitute the three types of Horner’s syndrome:

  • First order (central) Horner's syndrome where the nerve pathway may be damaged due to spinal cord lesions, hypothalamus tumor, and if the blood flow to the brain stem is suddenly interrupted
  • Second order (preganglionic) where the nerve pathway gets damaged by tumors in the chest cavity and trauma to the neck or chest due to accident or surgery
  • Third order (postganglionic) where problems with the nerve pathway are caused by middle ear infections, migraine, carotid artery lesions, or injury to the skull's base.

Other categories of Horner’s syndrome include:

  • Congenital Horner’s
  • Acquired Horner’s


Causes & Risk Factors 

In some cases, the cause remains unknown. However, Horner's syndrome is believed to arise from a problem with sympathetic nerves found in the neck, upper chest, and brain. These nerves regulate the pupil's size, heart rate, blood pressure, perspiration, and other bodily functions responsible for a person’s quick response to environmental changes. Acquired Horner’s syndrome can result from chest, brain, or neck abnormalities.  It can also be caused by neck surgery, stroke, spinal cord injury, or trauma to the neck.

Neuroblastoma, a tumor, can cause Horner’s syndrome in children. This tumor can develop in one part of the body then spread and affect the sympathetic nerves that help control the pupil. The other common congenital Horner syndrome causes include neck or trauma injury at birth and aorta defect present at birth. 

Signs & Symptoms 

Signs and symptoms may include:

  • Ptosis, a droopy eyelid
  • Sunken eye appearance
  • Lower eye pressure in the affected eye
  • In dim light, the affected pupil delays to open
  • Anhidrosis, which refers to little or no perspiration
  • Upside-down ptosis which is a slight rise in the lower eyelid
  • Anisocoria, a notable difference in the size of the pupils of both eyes
  • Miosis, where the affected pupil is persistently smaller than the other eye
  • In children aged less than one year, the color of the iris in the affected eye appears lighter
  • Flushing or a lack of redness on the side that is affected. Typically, after an emotional reaction or physical exertion, the affected side should appear red



Because Horner’s syndrome involves many other conditions, diagnosis may seem complex. Diagnosis may include:

Medical history
The doctor asks for information regarding injury, surgery, or other illnesses

Physical examination
The doctor checks for the signs and symptoms associated with Horner’s syndrome as well as other symptoms like pain

An ophthalmic examination
An eye examination by an ophthalmologist, or in most cases, a neuro-ophthalmologist, is performed. Tests include checking the pupil's response to certain stimulation. Dilating eye drops are put in both eyes; failure of a pupil to dilate may indicate Horner's syndrome

Imaging tests
Imaging tests are done to see if tumors, lesions, or structural abnormalities are present. These tests help to locate the anomaly and whether the growth is benign or malignant (cancerous). Such tests may include carotid ultrasound, MRI, Chest X-ray, X-ray imaging, or CT scan


Treatment for Horner’s syndrome involves treating the underlying condition since there is no specific treatment for the disorder. Once the underlying medical condition has been effectively treated, Horner’s syndrome will go away. Sometimes the symptoms may be so mild as not to require treatment. In case there is a family history of the condition, genetic counseling may help.

Surgery is considered if the tumor is malignant. Chemotherapy and radiation may follow surgical treatment.

Prognosis & Long-Term Outlook

The prognosis of Horner's syndrome depends on what caused it. For instance, the survival of a cancer patient depends on whether the entire cancerous cells have been eliminated. Generally, Horner's syndrome's typical signs and symptoms do not significantly impact the quality of vision and life of the patient. However, some symptoms may be serious and medical attention should be sought immediately, when they occur. These include vision problems, feeling dizzy, weak muscles, and sudden, severe headache or neck pain.

Prevention & Follow Up

Whatever is causing Horner’s syndrome will determine the follow-up schedule. For example, patients presenting with retinoblastoma may require a long-term follow-up period.