TL;DR: Nystagmus is rapid eye twitching signaling a balance system issue; seek veterinary care within 24-48 hours, or immediately if your dog cannot walk or is in extreme distress.
What is nystagmus in dogs and what does it look like?
If you notice your dog's eyes are twitching rapidly back and forth, up and down, or in a circular motion, they are experiencing a condition called nystagmus. This is not a disease itself, but rather a clinical sign that something is affecting your dog's vestibular system, which is responsible for maintaining balance and orientation. It can be quite disorienting for your pet and often feels like a severe case of vertigo or motion sickness.
Is my dog's rapid eye movement a medical emergency?
- Nystagmus is usually a medium-urgency condition that requires a veterinary exam within 24 to 48 hours.
- Contact an emergency clinic immediately if the twitching is accompanied by a sudden inability to walk or severe vomiting.
- Seek urgent help if your dog appears extremely distressed to rule out serious issues like stroke or toxin exposure.
Why should I record a video of my dog's eyes for the veterinarian?
- A clear video allows the vet to analyze the direction and speed of the twitching.
- The visual details help determine if the issue originates in the inner ear or the brain.
- Recording the behavior ensures an accurate diagnosis, especially if the eye movements are intermittent.
Clinical Context (Merck Veterinary Manual)
Unilateral lesions of the vestibulocochlear nerves can produce dysequilibrium with a head tilt toward the side of the lesion, accompanied by spontaneous positional, horizontal, or rotary nystagmus. Normal vestibular nystagmus (physiologic nystagmus) is seen as a few beats to the left as the head is turned to the left, and to the right as the head is turned to the right. Pathologic forms of nystagmus include pendular nystagmus, which lacks a fast or slow phase and exhibits arcs similar to a pendulum's movement. Brain stem auditory evoked response (BAER) testing can be used in diagnostics.
Chapter: Neurology
Source: The Merck Veterinary Manual, 11th Edition (Page 1216)