VCA Animal Hospitals

Why are my dog's pupils different sizes?

Published: May 07, 2012

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If you notice some irregularities in your canine companion's puppy-dog eyes, it's always a good idea to look a little closer. There are a number of issues that can arise in your dog's eyes, from corneal scratches and infections to glaucoma or other diseases.

Anisocoria in dogs is one irregularity to look for. Anisocoria is characterized by different-sized pupils in each eye, and can indicate a number of underlying conditions. Because anisocoria is a clinical sign, it is important for owners to work with the veterinarian to determine what the underlying cause might be.

Pupil irregularities can be caused by a corneal injury like an ulcer. They can also be a result of disease or injury to the brain and nerves near the eye. Retinal disease, cancer, glaucoma in dogs and other issues may be at play. VCA Animal Hospitals reports that if the anisocoria occurs suddenly, it should be treated as an emergency situation to prevent serious damage to your dog's vision.

When the veterinarian is examining the dog's eyes, he or she will focus on determining whether the issue is neurological or eye-related, according to The treatment will be based on the underlying medical condition.


General Practice

We have over 540 animal hospitals in 41 states that are staffed by more than 2,000 fully qualified, dedicated and compassionate veterinarians, with more than 200 being board-certified specialists. The nationwide VCA family of general practice hospitals give your pet the very best in medical care, providing a full range of general medical and surgical services as well as specialized treatments*: Wellness, Spay/neuter, Advanced diagnostic services (MRI/CT Scan), Internal medicine, Oncology, Ophthalmology, Dermatology, Cardiology, Neurology, Boarding, Grooming

*services may vary by location.

Our family of pet hospitals stands out by delivering the greatest resources in order provide the highest quality care available for your pets. By maintaining the highest standards of pet health care available anywhere, we emphasize prevention as well as healing. We provide continuing education programs to our doctors and staff and promote the open exchange of professional knowledge and expertise. And finally, we have established a consistent program of procedures and techniques, proven to be the most effective in keeping pets healthy.

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Specialty Care

Sometimes sick or injured pets need the care of a veterinary medical specialist. When that happens, VCA specialty hospitals work closely with the general practitioner veterinarians who refer cases to us in order to provide seamless veterinary care to your pet. When your pet is facing any kind of serious illness or injury, our specialty referral hospitals will provide the compassionate and expert care your beloved pet needs.

Our goal is to make sure that when you and your pet are in need that you have access to board certified specialists who are up to date on the very latest developments in their field. In our state of the art hospitals, our specialists also have access to the most sophisticated diagnostic and treatment tools and techniques from ultrasonography and endoscopy to CAT scans and even MRI.

We have twenty-eight specialty hospitals across the US so there may be one near you. Our specialized services include: cardiology, critical care, dentistry, dermatology, internal medicine, neurology, oncology, ophthalmology, radiology and surgery.

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Emergency Care

In case of emergency, please call us immediately. If it is after hours, check with a local animal hospital emergency clinic.