Glaucoma in Dogs: A Guide to this Painful, Blinding Eye Disease

A critical guide to glaucoma in dogs. Learn why this painful, high-pressure eye condition is a true emergency, how to spot the signs, and the treatments used to try to save vision and control pain.

Hey there, pet parents. Today we need to talk about a true medical emergency of the eye: Glaucoma. Glaucoma is a condition of increased pressure inside the eye. If it is not treated rapidly and aggressively, it will lead to permanent blindness and pain. It's critical for owners to know the signs of this devastating disease.

What is Glaucoma?

The eye is constantly producing a fluid called aqueous humor, which nourishes the structures inside the eye. This fluid is also constantly draining out of the eye through a filtration angle. There should be a perfect balance between production and drainage to maintain a normal intraocular pressure (IOP).

Glaucoma occurs when this drainage is blocked. The fluid can't get out, but the eye keeps producing more. This causes the pressure inside the eye to build up to dangerously high levels. This high pressure damages the delicate optic nerve and the retina, leading to irreversible blindness. It is also extremely painful.

There are two main types of glaucoma:

  1. •Primary Glaucoma: This is an inherited condition where the dog is born with an abnormal drainage angle. It is destined to develop glaucoma at some point in its life. It usually affects one eye first, but the other eye will almost always be affected later.
  2. 1Secondary Glaucoma: This is when the glaucoma is caused by another problem in the eye that blocks the drainage angle, such as a mature cataract, severe inflammation (uveitis), a tumor, or a lens luxation.

Breeds at Risk for Primary Glaucoma

Primary glaucoma is hereditary in many breeds, including:

  • •Cocker Spaniels
  • •Basset Hounds
  • •Beagles
  • •Siberian Huskies
  • •Boston Terriers
  • •And many others.

Spotting the Signs of Glaucoma: AN EMERGENCY

The signs of acute glaucoma come on suddenly and are a true emergency.

  • •A Red, Painful Eye: The white of the eye will be very red and bloodshot. The dog may be squinting, pawing at the eye, or holding it closed.
  • •A Cloudy or "Steamy" Cornea: The normally clear window at the front of the eye (the cornea) will look hazy or blue due to the high pressure.
  • •A Dilated Pupil: The pupil in the affected eye will be large and won't constrict in bright light.
  • •Vision Loss: The dog will be blind in the affected eye.
  • •Lethargy and Loss of Appetite: Because the condition is so painful, the dog will feel sick.

If you see these signs, you must get your dog to a veterinarian or an emergency clinic IMMEDIATELY. A delay of even a few hours can mean the difference between saving and losing the vision in that eye.

How Vets Diagnose Glaucoma

The diagnosis is made by measuring the intraocular pressure (IOP). This is done with a special instrument called a tonometer. A normal IOP in a dog is between 10 and 20 mmHg. In a dog with glaucoma, the pressure can be over 40, 50, or even 60 mmHg.

Your vet or a veterinary ophthalmologist will also perform a full eye exam to look for signs of damage and to determine if the glaucoma is primary or secondary.

Treatment: A Battle to Save Sight

The treatment for glaucoma has two goals:

  1. •Lower the pressure as quickly as possible to try to save vision.
  2. 1Control the pain.

Emergency Medical Treatment

When a dog presents in a glaucoma crisis, a cocktail of different emergency eye drops and sometimes intravenous medications are used to try to bring the pressure down rapidly.

Long-Term Management

  • •Medical Management: Most dogs with glaucoma will need to be on a combination of several different types of eye drops for the rest of their life. These drops work by either decreasing the production of fluid in the eye or by helping to increase its drainage.
  • •Surgical Management: For primary glaucoma, medical management alone often fails over time. A veterinary ophthalmologist may recommend a surgical procedure to improve the drainage of fluid, such as placing a shunt or using a laser to destroy the fluid-producing cells.

Prognosis: Guarded for Vision

Unfortunately, despite aggressive treatment, the long-term prognosis for maintaining vision in an eye with primary glaucoma is poor. Most dogs will eventually become blind in the affected eye.

Once an eye has become permanently blind and painful, the best and most humane treatment is often enucleation (surgical removal of the eye). While this sounds drastic, it removes the source of chronic pain and gives the dog a much better quality of life.

For dogs with primary glaucoma in one eye, it is critical to start preventative eye drops in the "good" eye to try to delay the onset of glaucoma in that eye.

Glaucoma is a tough disease. It requires lifelong medication and monitoring. But by being aware of the signs and acting fast, you can give your dog the best chance of preserving their precious sight for as long as possible.

Sources & Further Reading:

  1. •American College of Veterinary Ophthalmologists - Glaucoma
  2. 1VCA Animal Hospitals - Glaucoma in Dogs