Try the New Jerky Treats! Chicken or Beef Flavored!

Shop Now
Glaucoma in Dogs

Glaucoma in Dogs: Definition, Causes, Symptoms and Treatment

Glaucoma is a painful eye condition caused by increased intraocular pressure (IOP). Glaucoma is widespread in dogs among certain breeds, culminating in blindness if left untreated. 

Glaucoma in dogs results from defective genes or eye injuries and diseases. Genetic glaucoma is primary, while acquired glaucoma is secondary. 

Eye redness, squinting or blinking, cloudy eyes, tearing or eye discharge, visible blood vessels, enlarged pupils, decreased vision, eye bulging, and behavioral changes are common signs of glaucoma in dogs

Glaucoma is diagnosed with special ophthalmic tests such as tonometry, gonioscopy, and ocular ultrasound. 

Glaucoma is treated via a medical or surgical procedure. The vet determines the best glaucoma dog treatment based on the condition’s progression and individual factors. The main treatment goals for glaucoma are intraocular pressure (IOP) reduction and pain relief. 

A stress-free environment, a healthy diet, using a harness instead of a collar, and administering CBD oil are helpful aspects of dog glaucoma management. 

What is Glaucoma in Dogs?

Glaucoma in dogs is a painful, progressive, and latent-stage blinding eye condition caused by increased intraocular pressure (IOP). The popular term for glaucoma is high eye pressure. 

Canines are susceptible to glaucoma. Glaucoma occurs in about 1.7% of the dogs in North America, according to a report on “Glaucoma in Dogs” by MSD Veterinary Manual. 

Glaucoma in dogs is primary (inherited) or secondary (acquired). Primary glaucoma is prevalent among certain breeds of dogs. 

High eye pressure is the source of dog glaucoma. Increased IOP damages the optic nerve, retina, and optic disc, eventually leading to blindness. 

The intraocular pressure (IOP) in dogs is measured with a tonometer device. 

What is Intraocular Pressure (IOP) in Dogs?

Intraocular pressure (IOP) in dogs is the pressure caused by the fluid (aqueous humor) in the anterior (front) chamber of the eye. 

The ciliary body produces aqueous humor, which gives the eye shape and size and carries nutrients and oxygen. Excess aqueous humor drains from the eye through the drainage angle formed by the cornea and iris. 

The production and drainage of aqueous humor in the healthy eye are balanced, maintaining a normal dog eye pressure of 20-28 millimeters of mercury (mmHg). 

Glaucoma develops when the aqueous humor’s production rate exceeds the drainage rate, causing increased intraocular pressure or IOP (usually over 30 mmHg). 

What is the Difference Between Open-Angled Glaucoma and Closed-Angled Glaucoma?

The difference between open-angle glaucoma and closed-angle glaucoma is the mechanism of action. 

Open-angle glaucoma occurs when fluid does not drain due to resistance in the trabecular meshwork (main drainage pathway) while the angle between the cornea and iris stays open. 

Closed-angle glaucoma develops when the anterior chamber angle is physically obstructed, which happens acutely or chronically. 

Open-angle glaucoma is more common and less severe because it triggers a gradual increase in intraocular pressure. Closed-angle glaucoma has a sudden onset and causes acute pain. 

What Causes Glaucoma in Dogs?

The causes of glaucoma in dogs are listed below. 

  • Primary Glaucoma: Primary glaucoma is a genetic condition. Purebred dogs are at a higher risk of primary glaucoma than mixed dogs. The incidence of glaucoma is highest in Terrier breeds. Primary glaucoma is classified into open-angle and closed-angle glaucoma. 
  • Secondary Glaucoma: Secondary glaucoma results from eye injuries or diseases. Common eye conditions that cause glaucoma include uveitis (inflammation), cataracts, lens luxation, retinal detachment, and tumors. 
  • Congenital Glaucoma: Congenital glaucoma is hereditary and present at birth. Puppies born with congenital glaucoma have both eyes affected, but the glaucomatous changes are not always symmetrical. 
  • Other Factors: Glaucoma occurs following cataract surgery in dogs in some cases. “Phacoemulsification for cataract removal in dogs can lead to glaucoma,” reports a study “Development of Glaucoma after Phacoemulsification for Removal of Cataracts in Dogs: 22 Cases (1987-1997)” published in the JAVMA in 2001. 

How Does Age Impact the Risk of Developing Glaucoma in Dogs?

Age increases the odds of developing glaucoma in dogs. Glaucoma is common as dogs age. Primary glaucoma disproportionately affects middle-aged dogs and seniors. 

One of the main risk factors for glaucoma is decreased ocular blood flow or OBF in dog anatomy. Ocular blood flow is the distribution of blood within the eye. Aging decreases ocular blood flow. 

What Type of Dog Breed is More Prone to Develop Glaucoma?

The type of dog breed that is more prone to develop glaucoma is the Terrier breed. Examples include Boston Terriers, Wire Fox Terriers, Jack Russel Terriers, and Cairn Terriers. 

Breed-related glaucoma has gradually increased from 0.29% (1964-1973) to 0.46% (1974-1983), 0.76% (1984-1993), and 0.89% (1994-2002),” reports a study “Prevalence of the Breed-Related Glaucomas in Pure-Bred Dogs in North America” published in Veterinary Ophthalmology in 2004. 

The study found that American Cocker Spaniels, Basset Hounds, Wire Fox Terriers, and Boston Terriers consistently rank among the top 10 breeds for glaucoma prevalence. 

Other breeds prone to glaucoma are Chow Chows, Shar-Peis, Norwegian ElkHounds, Siberian Huskies, Dalmatians, Beagles, and Miniature Poodles. 

What are the Glaucoma Symptoms in Dogs?

The glaucoma symptoms in dogs are listed below. 

  • Eye Redness: Redness is a standard sign of inflammation, and inflammatory processes are central to glaucoma changes in dogs. 
  • Squinting or Blinking: Squinting is staring through partially shut eyes, and blinking is fast eyelid movement.  
  • Cloudy or Hazy Eye: Cloudy or hazy eyes in dogs with glaucoma occur when the high IOP causes severe damage to the optic nerve.  
  • Tearing or Discharge: Increased tearing and watery eyes are observed in the early stages of dog glaucoma. 
  • Visible Blood Vessels: Glaucoma causes increased vascular inflammation, resulting in enlarged and visible blood vessels.  
  • Enlarged or Dilated Pupil: The pupil in a glaucoma-affected eye is enlarged and less responsive to light. 
  • Sudden Changes in Behavior: Glaucoma in dogs is painful. Discomfort affects behavior and makes the dog moody, lethargic, or reluctant to eat. 
  • Decreased Vision: Decreased vision or blindness are common effects of glaucoma and are more striking in dogs with bilateral glaucoma. 
  • Bulging or Swelling of the Eye: Glaucoma causes bulging or swelling of the eye due to the accumulation of aqueous fluid on the front chamber.   

1. Eye Redness

Eye redness is a telltale inflammation sign. Inflammation is an important part of glaucoma. The medical term for redness of the white of the eye is conjunctival hyperemia. 

The redness resolves once the inflammation or glaucoma is under control. Cold compresses provide relief for red eyes in dogs.

2. Squinting or Blinking

Squinting is looking with semi-open eyes, and blinking is repetitive eyelid movement. Squinting and blinking are signs of discomfort and are known as blepharospasm. 

Pronounced squinting and blinking cease once the underlying problem is treated. Light-sensitive dogs with blepharospasm benefit from staying in dim environments. 

3. Cloudy or Hazy Eye

Cloudy eyes are widespread in dogs with glaucoma. The eyes often look hazy and bluish due to initial swelling. Cloudiness in the later stages is the result of optical nerve damage. 

Cloudiness is a red flag that warrants immediate veterinary attention. Cloudy eyes in dogs are permanent in cases of advanced glaucoma. 

4. Tearing or Discharge

Tearing is increased tear production. Watery eyes are common in glaucoma dogs. The tears mix with debris and skin cells, forming eye discharge and crusts. 

Managing the glaucoma resolves the testing. Owners are encouraged to clean the eye discharge in dogs several times daily because it is a breeding ground for bacteria. 

5. Visible Blood Vessels

The medical term for visible blood vessels is episcleral injection. Glaucoma is associated with inflammation. Inflammation makes the blood vessels look plump, distended, and easily visible. 

Episcleral injection looks scary but is not an emergency. The blood vessels return to normal as soon as the glaucoma-related inflammation resolves. 

6. Enlarged or Dilated Pupil

Enlarged or dilated pupil occurs in dogs with glaucoma. The term for a wide pupil is mydriasis. Glaucoma pupils constrict slowly and at a reduced capacity when provoked by a light source. 

Mydriasis is not a diagnosis and does not require special treatment. The pupil size decreases if the intraocular pressure is normalized. 

7. Sudden Changes in Behavior

Glaucoma is painful and causes behavioral changes. The vision loss-associated anxiety adds to the behavioral issues. 

Sudden changes in dogs with glaucoma include increased sleepiness, mood swings, and reduced appetite. Behavioral changes warrant veterinary attention. Try CBD oil for dog behavior problems as a home remedy. 

8. Decreased Vision

Decreased vision is common for dogs with glaucoma. Vision deficits and blindness are easier to spot in dogs with bilateral glaucoma. Dogs with one healthy eye compensate to a point. 

Signs of decreased vision include bumping into furniture or walls, reluctance to go out, and unexplained anxiety. Blind dogs learn to move coherently, but the situation initially confuses them.  

9. Bulging or Swelling of the Eye

Bulging or swelling of the eye is standard for dogs with glaucoma. The medical term for an enlarged eye is buphthalmos. Buphthalmos is defined as an increased eyeball volume. 

The eye bulging or swelling is managed once the intraocular pressure is under control. Enlarged eyes due to glaucoma are painful and require veterinary care.  

How to Diagnose Glaucoma in Dogs?

The instructions on how to diagnose glaucoma in dogs are listed below. 

  • Clinical Signs and History: The veterinarian takes the dog’s history and clinical signs and performs a complete body examination, which helps confirm the diagnosis.  
  • Ophthalmic Examination: The ophthalmic examination focuses on the eye and is performed with an ophthalmoscope. The ophthalmoscope allows the vet to visualize the deeper eye structures. 
  • Measurement of Intraocular Pressure (IOP): The intraocular pressure is measured with an electronic, handheld device known as a tonometer. Normal eye pressure in dogs is between 20 and 28 mmHg. Glaucoma-ridden dogs sometimes exhibit an IOP exceeding 40 mmHg. 
  • Gonioscopy: Gonioscopy is a procedure that evaluates the eye’s drainage angle. The test is performed with a special lamb and a slit lamp. The veterinarian drops a local anesthetic to the dog’s eye before performing a gonioscopy.
  • Ocular Ultrasound: Ocular ultrasound is a specialized diagnostic procedure that allows visualization of the farthest part of the eyeball. Some dogs tolerate ocular ultrasounds while conscious. 
  • Assessment of Visual Function: The veterinarian checks the pupil’s reaction time and reflexes to assess visual function. Canine glaucoma slows down and reduces the pupil's constriction capacity in the affected eye. 
  • Blood Tests and Additional Imaging: Blood tests (complete blood count, biochemistry panels) and additional imaging, like x-rays or CT scans, are performed to evaluate the dog’s overall health. 
  • Comprehensive Evaluation: The vet gathers and evaluates the results of all diagnostic procedures to reach a definitive diagnosis and determine the cause of glaucoma. 

What is the Treatment for Glaucoma in Dogs?

The treatment for glaucoma in dogs is medical procedures, including anti-glaucoma eye drops and anti-pain meds, or surgical.

Anti-glaucoma eye drops help drain excess fluid from the eye and include carbonic anhydrase inhibitors, prostaglandins, and beta-adrenergic blocking agents. The topical treatment is paired with analgesics or pain medications. 

The surgical treatment entails various techniques, such as shunt placement, cyclocryotherapy, and laser surgery. 

Complete eye removal, or enucleation, is recommended in severe cases when the option nerve is irreversibly damaged. The approach appears drastic but eliminates the pain and the need for continuous use of anti-glaucoma drops.  

The treatment approach for glaucoma is tailored individually based on other eye problems in dogs, age, and health. 

How can Glaucoma in Dogs be Managed?

Glaucoma in dogs can be managed by providing prompt treatment and symptom relief. Veterinary examinations and compliance with the treatment instructions are vital for successful management. 

Dogs with glaucoma benefit from a stress-free environment paired with simple dietary adjustments. An antioxidant-rich diet high in vitamin C and magnesium is recommended. 

Switching from a collar to a harness is integral to glaucoma management. Constrictive collars compress the dog’s neck, negatively affecting intraocular pressure.

What Happens if Glaucoma is Left Untreated?

Blindness occurs if glaucoma is left untreated. Unchecked glaucoma commonly “results in retinal ganglion cell death and eventual blindness,” according to a study titled “Canine Glaucoma: Pathophysiology and Diagnosis,” published in Compendium in 2009.

Treatment controls the glaucoma progression but does not restore lost vision. Untreated glaucoma is excruciating and harms the dog’s quality of life long before culminating in blindness. 

Primary, breed-related glaucoma is the leading cause of blindness in dogs, according to a study, “Genetics of Canine Primary Glaucomas,” published in The Veterinary Clinics of North America in 2015. 

What is End-Stage Glaucoma in Dogs?

End-stage glaucoma in dogs is the final stage of chronic glaucoma. Dogs with end-stage glaucoma clinically present with a so-called buphthalmos. Buphthalmos is the medical term for visible enlargement of the eye. 

The enlarged eye is completely blind. Vision loss signs are not always apparent in a dog with unilateral glaucoma because the healthy eye compensates for the ocular imbalance in the compromised eye. 

Are there Natural Remedies for Glaucoma in Dogs?

Yes, there are natural remedies for glaucoma. The remedies ease the symptoms and support general eye health but do not treat glaucoma directly. 

Popular home remedies for dogs with glaucoma include herbs (bilberry, rosemary, and burdock) and supplements (astaxanthin and coenzyme Q10).

Homeopathic home remedies include Aconitum Napellus 30c, Apis Mellificum 6c, Colocynthis 6c, Phosphorus 200c, and Belladonna 200c. 

Do not use natural remedies as a standalone glaucoma treatment. Glaucoma is a severe condition that requires prompt veterinary attention. Provide natural remedies as part of the pain management process once the vet approves. 

How can the Owner Provide Home Care for Dogs with Glaucoma?

The owner can provide home care for dogs with glaucoma by following the vet’s instructions. Following the guidelines and regular medication administration is vital for managing glaucoma in dogs. 

Minimizing stress and providing the dog with a nutritious diet are helpful home care tips. Stress has a negative impact and reduces the dog’s ability to combat health problems. Diet supports healing, especially foods for eye health, such as spinach, carrots, and fennel. 

Can CBD Oil Help Dogs with Glaucoma?

Yes, CBD oil helps dogs with glaucoma. CBD does not cure glaucoma but helps manage two important aspects of glaucoma, such as inflammation and pain. 

“Inflammation plays a crucial role in canine primary glaucoma, affecting the eye and potentially warranting anti-inflammatory medications as a core component of treatment,” reports a study on the “Role of Inflammation in Canine Primary Glaucoma,” published in Animals in 2023. 

CBD has excellent anti-inflammatory properties. CBD blocks COX-2 (cyclooxygenase-2) as the main inflammation trigger and reduces the levels of pro-inflammatory cytokines. 

Pet CBD works naturally through the endocannabinoid system (ECS) to relieve pain. CBD acts as a painkiller by interfering with specific pain-signaling pathways. 

CBD dosing is not an exact science, and dogs are given between 1 and 5 milligrams of CBD per 10 pounds daily. 

Starting with a lower dose and gradually increasing the amount helps in achieving the optimal CBD oil dosage and safety for dogs with glaucoma.