Canine glaucoma is an eye issue that occurs when the intraocular pressure, or 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 helps a ton in the process. But before that, let's first talk about what glaucoma actually is.
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
It's often associated with structural abnormalities in the eye, which pave the way for this eye condition. In dogs with the primary type, their drainage angle is too narrow or malformed.
These defects limit the flow of fluid and the amount that can be drained, which results 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 the drainage of fluid 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, which prevents fluid from the eye from draining properly.
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 Age Can Dogs Get Glaucoma?
While this condition can occur at any age, dogs usually experience primary glaucoma at the ages of 3 to 7. Secondary glaucoma in dogs often arises at any age due to the nature of the causes.
How Fast Does Glaucoma in Dogs Progress?
This eye condition can progress quickly or gradually. Acute glaucoma in dogs can develop as fast as 12 to 24 hours, which is often caused by a sudden obstruction within the dog’s drainage angle. Examples include lens displacement, tumor growth, and uveitis.
Chronic cases of glaucoma in puppies and dogs often take several months and years.
What Are the First Signs of Glaucoma in Dogs?
If your dog is experiencing an eye problem, there will be initial signs that can develop in intensity. These include:
Squinting or blinking more often. Dogs may squint because of mild eye pain as pressure begins to increase. It’s often mistaken for dust or dry eye, but it can be the first warning sign.
Cloudy or bluish cornea. Affected dogs may have a foggy cornea due to the buildup of fluid. This can indicate rising 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 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 the increased pressure, the eye will expand, resulting in a noticeable increase in size.
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 Check for Glaucoma in Dogs?
Checking and testing for glaucoma in dogs involves a few tests. These methods are used in different situations and ways to assess the different parts of your dog's eye, identify the cause, and rule out possibilities.
Tonometry
Tonometry is the primary method we use to diagnose canine glaucoma. It's a test that measures the amount of intraocular pressure.
Our vets will use a handheld device that gently taps the surface of your dog’s eye. It’s quick and non-invasive, also thanks to the numbing drops we will use. The results will be based on the readings. Here’s a general view:
Normal: 10 to 25 mmHg
Concerning: above 25 mmHg
Emergency: above 40 mm Hg
Gonioscopy
Another tool we can use is a gonioscopy. Here, we use a special lens to look at the angle where fluid drains inside the eye. This allows us to detect any structural issues, such as a narrow or abnormally formed drainage angle.
A gonioscopy is often the test that checks for primary glaucoma.
Additional Eye Tests
Depending on your dog’s condition, we may do additional tests to rule out other possibilities. These tests may include ophthalmoscopy, 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.
What Is the Treatment for Glaucoma in Dogs?
The main goals for the glaucoma in dogs treatment process are to reduce intraocular pressure, manage symptoms, and provide relief. Medicines will be the first option given to provide relief and comfort.
Prostaglandin analogs. Helps increase the outflow of fluid
Beta-blockers. Reduces fluid production in the eyes.
Carbonic anhydrase inhibitors. Slows down the production of fluid.
If the medication is not enough, glaucoma surgery for dogs will be recommended. The common techniques we use include:
Cyclophotocoagulation. A laser is used to destroy part of the ciliary body, which produces the fluid. This lowers the pressure by reducing fluid production.
Drainage Implants. A tiny tube is inserted to drain the fluid out of the eye. These shunts are generally used for primary or acute glaucoma in dogs.
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 outer wall will be left intact.
Can Glaucoma in Dogs Be Cured?
No, canine glaucoma can’t be cured. It can only be managed and treated regularly. Since glaucoma is a condition that damages the optic nerve, it doesn’t fully regenerate. This means that you can’t reverse the effects of this eye condition.
However, even if you can’t cure glaucoma in dogs, you can slow down its progression. Effective and consistent treatment options, coupled with early detection, allow dogs to live long and happy lives.
The Importance of Prevention and Early Detection in Canine Glaucoma
Canine glaucoma can’t always be prevented, that’s why early detection is crucial. If you notice even the slightest symptoms, then it’s essential to have your dog’s eyes checked.
Even if your dog isn’t a high-risk breed, it’s smart to include an eye exam during annual wellness visits. For high-risk dogs, regular checkups should include ocular exams.
Additionally, keeping your dog safe and clean helps a lot in preventing glaucoma and a variety of eye issues. By protecting your best friend against any eye injuries or illness, you can significantly reduce the risk of canine glaucoma.
“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. Nenad Misura
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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