Why Are My Dog's Eyes Darting Back and Forth?

beautiful Border Collie Dog

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You are relaxing with your dog and all the sudden notice his eyes are darting back and forth while his head is still. Although, this can be scary to see as a dog caregiver, it is important to know this is not normal and to contact your veterinarian.  

What Is Nystagmus?

Nystagmus is a medical term that describes when your dog’s eyes move rapidly and uncontrollably. They can move up and down, in a circle but most commonly seen is side to side movement. 

The movement can vary between slow and fast and occurs in both eyes. The eyes may shake more when looking in certain directions. Dogs with nystagmus may tilt or turn their head to see more clearly. 

Nystagmus, in and of itself, is not a disease but rather a symptom of an underlying condition. There are a variety of reasons your dog may exhibit this symptom. One of the most common conditions this is seen with is vestibular disease. 

Vestibular disease refers to a sudden, non-progressive disturbance of balance and nystagmus is commonly seen with this. It is more common in older dogs. It is also referred to as old dog vestibular syndrome and canine idiopathic vestibular syndrome.

The vestibular system is responsible for maintaining normal balance, coordinating eye movements, and sensing the position of the head and body into space.  The vestibular system has central components located in the brain, and peripheral components located in the inner and middle ear. 

Other potential causes for nystagmus including the following:

  • Middle/Inner infections 
  • Head trauma
  • Hypothyroidism
  • Encephalitis (inflammation of the brain)
  • Neoplastic tumors
  • Inflammatory and viral infections such as canine distemper
  • Exposure to toxins 
  • Stroke (loss of blood flow to the brain)

Depending on the underlying cause you may not see any other symptoms, or you may see different, accompanying symptoms. Dogs with nystagmus may also have other symptoms including loss of balance. head tilt, vomiting, walking in circle, falling over/disorientation, standing with their legs wide apart, and your dog may be less active than normal. 

Diagnosing the Reason For Your Dog’s Nystagmus

If your dog suddenly starts showing any of the symptoms mentioned above, contact your veterinarian immediately. Your veterinarian will start by performing a thorough exam and obtaining a history on your dog. Your vet may want to run blood work, a urinalysis, take radiographs, run an EKG screen, or get a blood pressure reading to check for any concurrent diseases. 

 Unfortunately, because some causes of nystagmus occur due to injury/trauma to the brain, a definitive diagnosis can only be made by specialized imaging, such as an MRI or CAT scan in those cases. While these are available in veterinary medicine, an owner usually has to go to a referral hospital for them and can be cost-prohibitive. If any underlying diseases are uncovered medications to better control those diseases will be prescribed. You vet will also want to rule out something called idiopathic vestibular disease, which is presents similarly but is a different illness altogether. Idiopathic refers to the exact cause of the disease being unknown, but this illness, also called Old Dog Syndrome, effects the vestibular system in your dog's inner ear. A dog suffering from vestibular disease will develop a head tilt, a circling gait, and may not want to eat their food any more. The symptoms are alarmingly similar to those of a stroke, but idiopathic vestibular disease is far more common in elderly dogs than a true stroke. 

Treating your Dog's Nystagmus 

How best to treat your dog's nystagmus depends entirely on what is causing your dog's nystagmus. A specific treatment will be based on the specific disease. If your dog's nystagmus is stemming from a chemical or toxin exposure, removing the substance may stop the nystagmus. If there is an infection, your vet may prescribe antibiotics and if your dog suffers from hypothyroidism, medications and dietary changes may improve symptoms. For other causes, such as vestibular disease, hospitalization and intravenous fluids may be required until the pet can eat and walk on their own. The clinical signs of vestibular disease including nystagmus often improve over a one- to two-week period.  Most dogs are completely recovered within two to three weeks with supportive care, although some will have residual symptoms such as a head tilt or mild "wobbling" for life. If your dog fails to improve or worsens, your veterinarian will perform advanced diagnostic testing. 

Regardless of the reason for your dog's nystagmus, seeking immediate veterinary attention is vital for your dog's health. Whether you see an emergency veterinarian or your regular veterinarian, they can help you figure out what is causing your dog's troubling eye symptoms and how best to tackle the problem.