List of Topics

SfC Home > Health > Animal Health >

Glaucoma in Pets

by Ron Kurtus (updated 18 January 2022)

Glaucoma is a disease of the eyes that occurs both in humans and animals. It is characterized by increased fluid pressure within the eye.

Glaucoma can result in rapid vision loss because of the damage that high pressure inflicts on the retina and optic nerve. Although veterinaries can often detect glaucoma, detection and treatment it is usually the best at an animal ophthalmologist.

Questions you may have include:

This lesson will answer those questions. Animal Health Disclaimer

Cause of glaucoma

Glaucoma is caused when the eye's internal drainage channels become obstructed.

The eye constantly produces a fluid called aqueous humor that helps to maintain the normal round shape of the eye. This fluid circulates inside the eye, nourishing cells and removing waste products, before then leaving the eye through tiny drainage channels. Glaucoma occurs when these channels become plugged or obstructed. When this happens, the fluid pressure will increase beyond levels compatible with the health of the eye.

This increased pressure can damage the retina optic nerve, resulting in partial or complete vision loss. Unfortunately, this vision loss is permanent and cannot be restored.

Types of glaucoma

In general, there are two types of glaucoma recognized in animals: primary and secondary glaucoma.


Primary glaucoma is the most common cause of glaucoma in dogs. It is caused when the drainage channels are unusually narrow or there are fewer channels than normal. As the dog ages, the drainage channels become smaller and eventually results in abnormally increased pressure within the eye.

This type of glaucoma usually occurs in both eyes, but often one eye is affected before the second eye. Primary glaucoma is usually inherited. Commonly affected dog breeds include the Cocker Spaniel, Samoyed, Chow Chow and Basset Hound, but it has been reported in numerous other breeds.


Secondary glaucoma is a consequence of some other eye disease. It occurs when another problem within the eye such as inflammation, tumor inside the eye, trauma, or a displaced lens blocks the drainage angle. It may develop rapidly or slowly. Secondary glaucoma is the most common cause of glaucoma in cats.

Diagnosing glaucoma

Just as you physician can test you for glaucoma, you get the best diagnosis and treatment from an ophthalmologist. The same is true for the diagnosis of glaucoma in animals. Many vets have the equipment needed to check for glaucoma, but you still get the more exact diagnosis from an animal ophthalmologist.

Measurements made

The diagnosis of glaucoma is based upon measurement of the pressure inside the eye, examination of the shape and color of the optic nerve and examination of the drainage channels or filtration angle. Using special equipment, the veterinary ophthalmologist examines the external and internal structures of your pet's eyes to detect any disorders that may be present.

The pressure inside the eye is measured with an instrument called a tonometer, similar to what is used with humans. If the pressure is elevated, or if the optic nerve looks unusual, the ophthalmologist will then examine the drainage channels to determine decide what type of glaucoma is present.


Depending on the type of glaucoma that is present, treatment may include eye drops or tablets to reduce the fluid pressure, surgery, or a combination of both. In a case of severe or chronic glaucoma where blindness is already present there are other treatments.


Glaucoma is caused when the eye's internal drainage channels become obstructed. Primary glaucoma is when the drainage channels are unusually narrow, Secondary glaucoma is a consequence of another eye disease. The diagnosis of glaucoma is based upon measurement of the pressure inside the eye and examination of the eye. Treatment can be medication or surgery.

Also see Treatment of Glaucoma in Pets

Appreciate your own vision, as well as your pet's

Resources and references

Ron Kurtus' Credentials


Navigation for a Blind Dog - Helping blind dog navigate house

Glaucoma in Dogs & Cats -

Animal Health Resources


(Notice: The School for Champions may earn commissions from book purchases)

Top-rated books on Animal Glaucoma

Top-rated books on Animal Health

Students and researchers

The Web address of this page is:

Please include it as a link on your website or as a reference in your report, document, or thesis.

Copyright © Restrictions

Where are you now?

School for Champions

Animal Health Topics

Glaucoma in Pets

Animal Health topics




Older pets

Also see

Let's make the world a better place

Be the best that you can be.

Use your knowledge and skills to help others succeed.

Don't be wasteful; protect our environment.

You CAN influence the world.

Live Your Life as a Champion:

Take care of your health

Seek knowledge and gain skills

Do excellent work

Be valuable to others

Have utmost character

Be a Champion!

The School for Champions helps you become the type of person who can be called a Champion.