Nystagmus in dogs is a medical term that describes when your dog’s eyes move rapidly and uncontrollably. This can be scary to see as a dog caregiver, and it is important to know this is not normal and to address it as soon as possible.

Learn the most common causes of nystagmus in dogs and how to treat it.

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 or in a circle, but most commonly seen is side-to-side movement. Nystagmus, in and of itself, is not a disease but rather a symptom of an underlying problem with the vestibular system, which controls balance.

The movement can vary between slow and fast, and it generally occurs in both eyes. The eyes may shake more after a sudden movement or position change. Dogs with nystagmus may have a head tilt or turn that accompanies the abnormal eye movement.

Causes of Nystagmus in Dogs

There are a variety of reasons your dog may exhibit problems with the vestibular system, resulting in nystagmus.

• Middle/inner ear 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 part of the brain)

Depending on the underlying cause you may or may not see any other signs accompanying the nystagmus. Dogs with nystagmus may also have other symptoms, including loss of balance, head tilt, vomiting, walking in circles, falling over/disorientation, standing with their legs wide apart, or decreased activity.

How a Vet Diagnoses Nystagmus in Dogs

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 may want to run blood work, perform a urinalysis, take radiographs, or obtain a blood pressure reading to check for any concurrent diseases. The examination and testing can help determine if the nystagmus is more consistent with central (in the brain) or peripheral (inner ear or idiopathic) vestibular disease.

Unfortunately, because some causes of nystagmus occur within the brain, a definitive diagnosis can only be made by specialized imaging, such as an MRI or CAT scan in those cases. While these tests are available in veterinary medicine, evaluation by a veterinary neurologist may be recommended for dogs that are showing central (brain-related) causes for their nystagmus.

How to Treat Nystagmus in Dogs

The best treatment for your dog's nystagmus depends on the severity and cause.

Uncomplicated cases treated at home often make good progress toward recovery in the first 2-3 days with the help of:

• Nausea medications
• Activity restrictions
• Supported walks

Hospitalization for supportive care with IV fluids and medications may be recommended for dogs that are more severely affected until they can eat and walk on their own.

Medications may be recommended for problems like ear infections, hypothyroidism, or high blood pressure, but regardless of the reason for your dog's nystagmus, seeking immediate veterinary attention is vital for your dog's health.