Canine glaucoma is an eye condition that occurs when intraocular pressure (the pressure inside the eye) increases. This damages the optic nerve and retina, potentially leading to permanent blindness if left untreated.
While this can be concerning, there are ways to manage it. Early detection is extremely important, helping delay progression and manage the condition. But before that, let’s talk about the main types.
Key Takeaways
Glaucoma in dogs is a condition in which the eye experiences increased intraocular pressure, which can damage the retina and optic nerve.
It can be caused by genetics, uveitis, lens luxation, cataracts, intraocular tumors, eye injuries, and intraocular bleeding.
Tonometry and gonioscopy are common diagnostic methods. Glaucoma is also treated through medications and surgery.
What Are the Types of Glaucoma in Dogs?
Glaucoma comes in two main types: primary and secondary.
Primary
This type is inherited and common in certain dog breeds. These include:
Basset Hounds
Boston Terriers
Primary glaucoma is often associated with structural abnormalities in the eye. In dogs with the primary type, their drainage angle is too narrow or malformed. These defects limit fluid flow and the amount that can be drained, resulting in a gradual buildup of pressure.
Secondary
Secondary glaucoma in dogs is a type caused by other eye conditions and health issues. In many cases, only one eye is affected.
Uveitis. The inflammation results in a buildup of cells, proteins, and other debris, causing a clog that hinders fluid drainage from the eye.
Lens Luxation. The lens becomes loose and dislocated, shifting forward or backward. This can physically obstruct fluid flow and block drainage, causing acute glaucoma in dogs, a painful medical emergency.
Cataracts. Advanced cataracts can trigger blockage through lens-induced uveitis or the dissolution of cataracts. These conditions cause physical obstruction, preventing fluid from draining properly from the eye.
Intraocular Tumors. Tumors that grow within the eye can physically obstruct the iridocorneal angle, the pathway through which fluid drains.
Eye Trauma. Injuries and blunt force to the eye can damage the trabecular meshwork, the drainage system of the eyes. Other results of injuries can include inflammation, lens displacement, intraocular bleeding, and cataracts, all of which can lead to glaucoma.
Intraocular Bleeding. Bleeding within the eye can develop clots, which impair fluid flow.
What Are the Symptoms of Glaucoma in Dogs?
The main signs will be observed around the eye area and in your dog’s overall behavior. Below are the usual symptoms our veterinarians note at the clinic and those reported by our clients.
Squinting or blinking more often. Dogs may squint due to mild eye pain as intraocular pressure begins to rise. It’s often mistaken for dust or dry eye, but it can be the first warning sign.
Cloudy or bluish cornea. Some dogs may have a cloudy or hazy appearance in their eyes, which may indicate fluid buildup and increased intraocular pressure.
Redness in the white part of the eye. The blood vessels can swell, leading to a bloodshot appearance of the eye.
Hesitation in dim light. Dogs with glaucoma may start bumping into furniture or have visible trouble navigating. They might prefer rooms with dim lighting.
Teary eye. In some cases, your dog’s eyes will start to tear and show discharge.
Unequal pupil sizes. Pressure changes can affect how the pupil responds to light, leading to clear asymmetry.
Bulging or enlarged eye. Due to increased pressure, the affected eyeballs may bulge, leading to a noticeable enlargement.
Severe eye pain. Dogs with glaucoma may seem withdrawn, lethargic, or irritable. Some may rub or paw at their eyes, while others will be less interested in eating and playing.
How Do Vets Diagnose Canine Glaucoma?
Checking and testing for glaucoma in dogs involves a few diagnostic tests. These methods are used to assess the different parts of your dog's eye, identify the cause, and rule out possibilities.
Ocular Exam
Our pet ophthalmologists will check for physical signs present on your dog’s eyes. We’ll take note of the usual symptoms before proceeding to the confirmatory tests.
Tonometry
Tonometry is the primary method we use to diagnose canine glaucoma. It works by measuring the amount of pressure inside the dog’s eyes.
Our vets will use a handheld device that gently taps the surface of your dog’s eye. It’s quick and non-invasive, especially since we’ll be using numbing drops to ensure comfort. The results will be based on the readings. Here’s a general view:
Reading | Description |
|---|---|
10-25 mmHg | Normal |
> 25 mmHg | Concerning; strongly suspects glaucoma |
> 40 mmHg | Emergency |
Gonioscopy
After administering anesthetic drops, our vets place a goniolens on the dog’s eyes to visualize the drainage angle. By doing so, we can check if it’s open, narrow, or closed. We can also detect malformations or blockages in the angle using this method.
Additional Eye Tests
Depending on your dog’s condition, we may do additional tests to rule out other possibilities. These tests may include ultrasound, eye staining tests, and a slit lamp examination.
These can help us further assess your dog's cornea, retina, iris, and lens. They also help us determine the cause, which can be corneal ulcers, tumors, internal bleeding, or lens displacement.
How Is Glaucoma in Dogs Treated?
The main goals of glaucoma treatment in dogs are to reduce intraocular pressure, manage symptoms, and provide relief.
Medications
Medicines will be the first option given to provide relief and to manage the condition.
Prostaglandin analogs. Helps increase the outflow of fluid and are effective for acute cases.
Beta-blockers. Reduces fluid production in the eyes, but often used in conjunction with other medications.
Carbonic anhydrase inhibitors. Slows down the production of aqueous humor in the eye.
Osmotic diuretics. Often used in emergencies, as they rapidly lower intraocular pressure by dehydrating the eye.
Pain relief medications. Manages and alleviates the pain experienced by the affected eye.
Surgery
If the medication is not enough, glaucoma surgery for dogs will be recommended. The common techniques veterinarians perform include:
Cyclophotocoagulation. A laser is used to destroy part of the ciliary body, reducing the production of aqueous humor. By doing so, it reduces fluid buildup.
Drainage Implants. This works by inserting a tube into the eye’s anterior chamber, diverting the excess aqueous humor into a small plate under the conjunctiva. The fluid will then be absorbed by the blood vessels.
Enucleation. In severe cases, the dog’s eye will be removed and sutured shut.
Evisceration. Alternatively, only the contents of the eye will be removed while the other wall will be left intact.
Can Glaucoma in Dogs Be Cured?
No, canine glaucoma can’t be fully cured. It can only be managed and treated over the long term. Since it damages the optic nerve and retina, the effects cannot be reversed. The course of treatment only focuses on delaying the progression of the condition and alleviating the symptoms.
The Importance of Prevention and Early Detection in Canine Glaucoma
Since glaucoma can’t always be prevented, early detection is crucial. Routine wellness exams help our vets detect the hidden issues that aren’t always visible.
Even if your dog isn’t a high-risk breed, it’s smart to include an eye exam during a wellness check. For high-risk dogs, regular checkups should include eye exams.
Additionally, keeping your dog safe and clean significantly reduces the risk of glaucoma and other eye issues that may contribute to this condition.
“Your dog depends on you to see what they can’t. The smallest signs in their eyes can lead to the biggest difference in their life.”
- Dr. Soheyl Simaei
Final Thoughts
Canine glaucoma is a serious and painful eye condition that robs dogs of their sight and quality of life. This eye condition demands immediate attention and lifelong management. Fortunately, there are plenty of treatment and management options available.
All you need to do is stay alert and keep a close eye on your best friend.
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