Canine Glaucoma – Causes, Symptoms & Treatment

The description of glaucoma is rapidly changing nowadays as our grasp of the pathogenesis of optic nerve and retina impairment improves every day.

Simply, canine glaucoma is a group of disorders that can be described generally as an elevation in intraocular pressure (IOP) with decreased drainage of aqueous humor resulting in the optic nerve and retinal damage.

Along with cataracts, Glaucoma is the leading cause of impaired vision or irreversible vision loss in dogs. Regardless of medical or surgical treatment, 40 percent of dogs will become blind in the affected eye within the first year.

Glaucoma is classified according to the duration of glaucoma (acute or chronic) and the underlying causes of the decreased AH drainage (primary or secondary).

• A cloudy, hazy, or ‘bluish coloration’ to the eye.
• The appearance of vessels in the white of the eye / Redness of the white of the eye.
• Swollen or bulging eye.
• Dilated pupil – or pupil does not respond to light.
• Fluttering eyelid.
• Vision problems (bumping into objects, difficulty finding toys, walking gingerly).
• Signs of pain: squinting or watering the eye, sleeping more, tilting the head, or being head shy.

Long-term, advanced disease:

• Buphthalmos(one or both eyeballs are larger than normal).
• Advanced degeneration within the eye.
• Obvious loss of vision.

Symptoms of glaucoma due to secondary eye infection or secondary glaucoma includes:

• Cloudy, hazy appearance in front of the eye.
• Redness of the blood vessels in the whites of the eyes.
• increased intraocular pressure.
• Inflammatory debris, nonclearing blood in the front of the eye (floaters).
• Possible sticking of the iris to either the lens or the cornea.
• Possible constriction of the pupil.

Glaucoma in dog treatments will depend on the underlying health issue and severity of the condition.

Medications:

Most glaucoma prescriptions (to alleviate pain and preserve the animal’s vision) come in the form of eye drops, ointments, or topicals, all of which require a vet’s authorization.

β Blockers: Betaxolol, Timolol.

Carbonic Anhydrase Inhibitors: Methazolamide, Acetazolamide, Brinzolamide, Dorzolamide.

Cholinergic Agents: Pilocarpine, Demecarium bromide.

Prostaglandin Analogues: Latanoprost, Travoprost and bimatoprost.

Hyperosmotic Agents: Mannitol, Oral glycerin.

Veterinary ophthalmologists suggest Medical treatment combined with surgery in advanced or severe cases.

If blindness has developed or in cases that do not respond to medical treatment, surgical removal of the eye (enucleation) may be recommended to relieve the pain and discomfort.

Glaucoma predisposed breeds should have their eyes checked regularly so that cases can be detected and treated as early as possible.

Always watch for any abnormalities with the eyes and report them to your vet as soon as possible.

Avoid tight collars or harnesses around the neck to reduce intraocular pressure.

Provide supplements that promote eye health that may be useful in preventing glaucoma from developing.

Since untreated glaucoma can result in pain and blindness, prevention (if possible) only will improve the pet’s quality of life. Also, medication can help delay progression, and especially surgical intervention to treat glaucoma can be expensive, but most pets lose vision in one or both eyes within two years without surgery.

Primary glaucoma can’t be prevented because it’s the result of genetics. Pet owners have to be careful about the symptoms and address signs of pressure build-up in the eyes.

On the other hand, secondary glaucoma is preventable by maintaining pets’ optimal health, avoiding trauma to their orbital area, and seeking timely treatment for infections (especially those related to the eyes).

While there is no definitive way to find out whether a dog is genetically predisposed to glaucoma or not, there are a few tests such as the gonioscopy and ocular ultrasound that can be used to examine the pet’s eyes to evaluate the risk.

When the condition is diagnosed early, follow-up appointments will be planned to find out if the condition is worsening or if treatment is helping.

Beagle, Basset Hound, Boston Terrier, Cocker Spaniel, Shar Pei, Siberian Husky, Samoyed, Labrador Retriever, Toy Poodle, Chow Chow, Terrier, Cavalier King Charles Spaniel, Labrador, Golden Retriever, Rottweiler, Young Females, Puppies

1. Primary Glaucoma (genetic) - IOP measured using tonometer – 25-30mmHg.

• Primary open-angle glaucoma (POAG) is the most common primary glaucoma.
• Primary closed-angle glaucoma (associated with goniodysgenesis).

Primary glaucoma is further classified based on the state of the drainage angle.

The angle may be open (in which case the obstruction is further downstream), narrow or closed-angle.

Secondary Glaucoma - (the result of separate or concurrent eye condition causing intraocular fluid drainage to be blocked or slowed).

(IOP: 10-30mmHg).

• Lens luxation.
• Cataracts.
• Cataract surgery.
• Tumors.
• Inflammation (uveitis).
• Retinal detachment.

2. Acute Or Chronic Glaucoma:

Acute Glaucoma: Short duration and this form of glaucoma cause symptoms you can't ignore.

Chronic Glaucoma: This is the most common form of glaucoma. This develops so slowly that owners may not even notice it.

Primary glaucoma has no reliable cure but it is manageable. There’s always the possibility of a cure with respect to secondary glaucoma. Acute glaucoma can often be treated so that vision is restored for some time. In chronic glaucoma, constant medical treatment will be required to keep the disorder under control.

Overall, the prognosis for vision varies a great deal for each dog. Therefore, the short-term prognosis variable and the long-term prognosis for vision are actually poor but with appropriate management, vision may be retained for many years.

• Low-carb dog food/ Whole, unprocessed foods.
• Lean meat protein.
• Vitamin C and bioflavonoids: Brussel sprouts, spinach, broccoli, kale, pineapple, papaya, and strawberries etc.,
• CoQ10 foods-organ meats, muscle meats (beef, pork), legumes, nuts, seeds etc.,
• Omega Fatty Acids- salmon, tuna, cod, halibut, trout, herring fish.
• Blueberries, broccoli, carrots.
• Sweet potato, pumpkin, tomato.
• Leafy green vegetables (lettuce, spinach, salad greens, parsley, collard greens ).
• Intake of dietary nitrates- mainly from green leafy vegetables.

Prognosis will largely depend on the underlying health issue that causes glaucoma and the severity of the condition.

Sometimes, Lifelong treatment will be needed to keep the condition under control. Visiting the vet on a regular basis is required in order to have the intraocular pressure assessed.

This is also to assess how the pet is responding to the treatment and adjust the therapy if necessary.