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Glaucoma in Dogs: Symptoms & Diagnosis

By Colleen Williams and medically reviewed by Sarah Wallace DVM
published: July 24, 2017 - updated: October 5, 2023 • 3 min. read
Dog getting drops in the eye

Key Takeaways

  • Glaucoma affects humans and dogs and can lead to vision loss and optic nerve damage.
  • Signs of glaucoma are excessive blinking and a cloudy appearance in the eye.
  • A vet will test the dog’s eye pressure with a tonometer.
  • Prescription medication or surgery may be recommended for treatment.
  • Having pet insurance can dramatically reduce the cost of glaucoma care in dogs.

Just like humans, glaucoma in dogs is an eye condition where intraocular pressure (fluid pressure inside the eye) builds and there is insufficient fluid drainage which can cause optic nerve damage, vision loss and further complications. While many dog breeds can be genetically predisposed to glaucoma, any dog could be diagnosed. “Early diagnosis almost never happens,” says Dr. Gary Richter, MS, DVM. “Pet owners see it when the eye is red and painful, and in many cases, it’s already advanced and difficult to manage.”

Glaucoma tends to occur in older dogs, and those with cataracts can be at greater risk. It is classified as primary and secondary: Primary glaucoma means there is no underlying disease whereas secondary glaucoma is caused by an underlying disease, infection, irritation, injury or tumor.

Signs and symptoms for sudden primary glaucoma

  • High pressure within the eye, as tested by a vet
  • Excessive blinking
  • A receding look to the eyeball (or physical recession)
  • Increased prominence of the blood vessels in the whites of eyes
  • Cloudy appearance at front of the eye
  • Dilated pupil that does not respond to light
  • Vision loss, although difficult to determine – most pets compensate extremely well with the loss of vision in one eye, so you may not realize your dog is blind.
  • Pain – Dogs usually have a higher level of pressure than humans when diagnosed with glaucoma, and they often do not let you know they’re suffering. Usually glaucoma results in headaches and migraines – you may notice your dog doesn’t want to play, eat, and is acting irritable.

Signs and symptoms for the more common diagnosis of secondary glaucoma are similar to the primary signs above, but also include:

  • Inflammatory debris visible in the front of the eye
  • Possible constriction of the pupil, rather than dilation
  • Iris complications – pet parents report that the iris (the colored circle around the pupil) “sticks” to the cornea or lens; best practices indicate that if your dog’s eye looks strange, call your veterinarian.
Protect your pet

Diagnosing Glaucoma

If you suspect your dog is suffering from glaucoma, get to the vet immediately! It is recommended to have emergency treatment as soon as possible to save vision in your pup’s eye.

While at the veterinary hospital, give a good rundown of your dog’s health history, especially any recent trauma to the eye – even minor scrapes are important to note. Your vet will test your dog’s eye pressure with a veterinary tonometer, a little gadget that looks almost like a thermometer. If the diagnosis is glaucoma, your vet may refer your pup to a veterinary ophthalmologist to check out both eyes.

Treatment for Glaucoma

Based on the diagnostics, your veterinarian will determine what further treatment may be needed – whether that is prescription medicine or surgery is up to the condition of your pup. Prescription drugs lower the pressure in your pup’s eye to get it down to a normal range in order to salvage vision, and Cyclocryotherapy, a draining procedure where cells are frozen to stop producing fluid, is another treatment option. Ultimately, though, many dogs suffering from glaucoma have the eye removed.

Most dogs adjust over time to the loss of their eye, especially if they’d been blind for a long period of time before removing the eye. Pet parent Kathie of Buddy Lee says of the process: “We really thought [Buddy Lee’s] quality of life would be affected – but he was fine! His personality is still the same, he just looks like he’s winking.” Dogs will need to be monitored outdoors, as they are more vulnerable, but overall, they adapt well to their situation, depending on their other keen senses and sometimes, dogs in their pack that act as guides.

More than half of dogs with primary glaucoma will have symptoms and develop glaucoma in their unaffected eye within 8 months of the first diagnosis. Therefore, it’s important to schedule follow-ups with your vet to prevent and treat. Having pet insurance can help immensely – while surgery is no doubt expensive, diagnostic testing can be costly too and monthly prescriptions can add up. Find out more by checking out our report on the Cost of Pet Health Care.

The content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian or other qualified health provider with any questions you may have regarding a medical diagnosis, condition, or treatment options.

colleen williams
By Colleen Williams

Over the past decade, Colleen has written about health, wellness, beauty, and even pets for The New York Times, The Cut, Refinery29, xoVain, Healthy Paws Pet Insurance, and Seattle Met Magazine, as well as many beauty brands. She has a BFA in Art History from the University of New Mexico and an AAS in Fashion Design from Parsons School of Design in New York.

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Sarah Wallace DVM profile photo
By Sarah Wallace DVM

Dr. Sarah Wallace is the vice president of telehealth at Galaxy Vets, based in Fort Collins, Colo. She is actively working to increase access to veterinary care, to develop more effective communication strategies to bridge the gap between veterinarian knowledge and pet parent understanding and build happy and sustainable veterinary teams. Dr. Wallace studied biology at Lafayette College in Pennsylvania and attended veterinary school at Western University of Health Sciences in California. After graduation, Dr. Wallace started working with Just Food for Dogs, an innovative pet food startup out of southern California advocating fresh, whole-food diets for dogs. She also completed a small animal rotating internship at San Francisco Veterinary Specialists - receiving one-on-one training with San Francisco's top veterinarians in internal medicine, neurology, dermatology, oncology and surgery. After working in clinical practice, Dr. Wallace joined the field of telehealth. Dr. Wallace writes and reviews blog content for Healthy Paws Pet Insurance. Dr. Sarah Wallace on LinkedIn Cardinal Veterinary Works Consulting

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