What you see. The starting point for addressing any equine health related issue is your observation.


Eye is Making Abnormal Rapid & Jerky Movements


When a horse moves its head around, their brain and inner ear control eye movement. This is known as normal or physiologic nystagmus. When this system is damaged, inappropriate or jerking movements of the eye are known as pathologic nystagmus. These abnormal movements can be seen when the horse's head is still.

Abnormal nystagmus is rare in horses and is most likely associated with brain damage, recovery from anesthesia, or middle ear dysfunction. Nystagmus is most often seen in horses that are suffering from severe brain injury, as can occur after a horse rears over backwards and lands on their poll. In most cases, horses with obvious pathologic nystagmus are lying on the ground or are in danger of falling to the ground.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the horse seems to be in distress.
    • If you notice apparent wobbliness or weakness, in addition to this sign.
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If you consider this a chronic and relatively mild problem that is not changing rapidly.
    • If the horse seems to be moving freely, and has a normal appetite and attitude.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.

your role


What To Do

Due to the potential severity of the condition causing this observation, call your vet immediately and do not attempt to handle the horse any more than absolutely necessary.

What Not To Do

Do not handle a horse that is showing obvious abnormal eye movement. They may be in danger of falling.

your vet's role

Your vet will perform a complete physical and neurologic examination to detect other abnormalities that may give clues to the condition. Blood tests and head x-rays may be helpful in some cases.

NOTE: This observation is associated with Rabies, which is very rare in horses but does occur. As a precaution, wear gloves when handling a horse exhibiting this sign.
Questions Your Vet Might Ask:
  • Is there any other sign of injury or an accident?
  • Describe what the horse is doing now?
  • What are the results of the Whole Horse Exam (WHE)?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
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Treatments Your Vet May Recommend

A way to resolve the condition or diagnosis. Resolving the underlying cause or treating the signs of disease (symptomatic treatment)

Very Common
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Author: Doug Thal DVM Dipl. ABVP