Understanding Glaucoma in Pets: Symptoms, Causes, and Treatment Options
What is Glaucoma in Pets?
Glaucoma is a condition that results in increased pressure inside the eye, leading to potential damage to the optic nerve and vision loss if left untreated. The eye is a fluid-filled structure, and glaucoma occurs when there is decreased drainage of this fluid or, to a lesser extent, increased production of fluid. Intraocular pressure (IOP) is the measurement of pressure inside the eye, with normal ranges being 10-20mmHg for dogs and cats, and 15-23mmHg for rabbits and guinea pigs.
What Causes Glaucoma in Pets?
Glaucoma can be classified into two categories:
- Primary Glaucoma: This form of glaucoma occurs in a structurally normal eye but is caused by genetic factors that affect the internal drainage system of the eye. Breeds prone to primary glaucoma include Beagles, Cocker Spaniels, Shih Tzus, Jack Russell Terriers, and others. Primary glaucoma is rare in cats.
- Secondary Glaucoma: This type of glaucoma is caused by another condition, such as eye injuries, infections, or tumors. Common underlying causes include:
- Uveitis (inflammation of the eye)
- Cataracts
- Eye trauma (e.g., scratches or injuries)
- Tumors or growths in or around the eye
- Lens displacement
- Diseases like Feline Infectious Peritonitis (FIP) in cats or Tick Fever in dogs
Symptoms of Glaucoma in Pets
It is crucial for pet owners to recognize the signs of glaucoma in their pets, as untreated glaucoma can lead to permanent blindness. Symptoms may include:
- Painful Eye: Your pet may squint or frequently rub its eye. They might also try to avoid you touching the affected eye. Eye pressures in dogs and cats can go up to 30-50mmHg, it can be very painful.
- Redness in the Eye: Look for redness on the whites of the eye.
- Bulging Eye: One eye may appear larger, or bulging compared to the other, or looks to be bulging out of the head.
- Cloudy Cornea: The surface of the eye may appear whitish or bluish.
- Sudden Blindness: Pets with glaucoma may seem disoriented, bump into things, or avoid walking outside. If blindness is only in one eye, your pet may adjust and compensate without showing obvious signs. Blindness occurs due to pressure damage on the optic nerve.
- Inappetence: A lack of interest in food can result from pain or vision loss.
Note: Not all symptoms will be present in every case. Your pet may show only one or a few signs of glaucoma.
What to Do if You Suspect Your Pet Has Glaucoma
If you suspect your pet may have glaucoma, contact your vet immediately. Pets with glaucoma for over 72 hours can experience permanent blindness. Unfortunately, many owners do not realize their pets are losing vision until it is too late, as pets often compensate well with their remaining eye.
How Your Vet Can Help with Glaucoma Diagnosis and Treatment
Your veterinarian can diagnose glaucoma by using a tonometer to measure your pet’s intraocular pressure (IOP). If the IOP is above 20mmHg, your vet may recommend eyedrops to lower the pressure and help manage the condition. They will also check for underlying causes of the glaucoma and provide appropriate treatment.
Additional measures, such as reducing stress or switching from a collar to a harness, can also help reduce IOP in some cases.
Surgical Treatment for Severe Cases of Glaucoma
In some cases, medical therapy (such as eye drops and oral pain relief) may not be enough to control the pressure, and your pet may experience ongoing discomfort. In these instances, your vet might recommend enucleation surgery—the removal of the affected eyeball to relieve pain.
Although the idea of eye removal can be unsettling, many pets, especially dogs and cats with primary glaucoma, adapt very well. After the procedure, pets often do better without the constant pain of high intraocular pressure.
Some pets, especially those with primary glaucoma, may require both eyes to be removed. However, their quality of life remains good, as they will rely on their sense of smell and hearing to navigate their environment.