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Glaucoma Symptoms for Dogs

| Updated September 26, 2017

Glaucoma is an increase in eye pressure. Canine glaucoma develops due to a build up of fluids within the eye. This extra fluid puts pressure on the optic nerve and results in partial or full blindness. If you observe signs of glaucoma in your dog, treat it as an emergency and seek veterinary care immediately. Glaucoma progresses rapidly, sometimes over the course of just a few days, according to the "Clinical Textbook for Veterinary Technicians."

Changes in Physical Appearance

Dogs with developing glaucoma symptoms have red-rimmed eyes. This redness appears similar to conjunctivitis, an infection and inflammation of the lining of the eyes. The initial onset of glaucoma can easily be mistaken for conjunctivitis, according to the "Clinical Veterinary Advisor." In addition to red-rimmed eyes, the blood vessels in the sclera, or white portion of the eye, increase and swell, causing the affected eye or eyes to look blood-shot. After redness sets in, the lenses of the eyes start to look cloudy. Advanced glaucoma causes the dog's eyes to bulge in their sockets due to a build-up of fluids and pressure in the eye. This may be readily apparent or incredibly slight. The dog's pupil may remain permanently dilated. Glaucoma usually affects one eye before the other, according to the "Merck Veterinary Manual," making it necessary to check both eyes for symptoms.


Dogs with glaucoma will exhibit extra tearing or discharge from the eyes. This is one way the dog's body deals with the extra pressure in the eye. The excess tearing serves to lubricate the eye socket in an attempt to lessen the pain associated with glaucoma, as stated by the "Clinical Textbook for Veterinary Technicians."

Light Sensitivity

Light sensitivity, or photophobia, is readily apparent in dogs with glaucoma. The pressure caused by the disease makes exposure to light incredibly painful. Even the light given off by a regular lightbulb may cause too much pain for a dog to handle, according to "Shelter Medicine for Veterinarians and Staff." Dogs exhibiting light sensitivity try to avoid brightly lit rooms and sunlight. They may vocalize in pain when exposed to ambient lighting or when a light is shone directly in their eyes. Dogs with pain and photophobia also might try to rub their face or eyes on the floor or their own body in an attempt to alleviate the pain.

Corneal Ulcers

Dogs with advanced glaucoma may be unable to fully close their eyes. This, in conjunction with the change in the physical appearance of the eye, can lead to corneal ulcers. Corneal ulcers are painful sores on the eye itself that open the dog up to secondary infections.