Canine glaucoma is a serious and painful eye condition that can lead to complete blindness if left untreated. It’s characterized by the increase in intraocular pressure, causing optic nerve damage.

Glaucoma is a medical emergency and should be treated as such to prevent any permanent damage.

In this guide, we’ll walk you through everything you need to know about glaucoma in dogs, from what it is to how it is treated and prevented. 

What are the Types of Glaucoma in Dogs?

There are two main types of glaucoma in dogs, namely: 

Primary 

This type is inherited and more common in certain breeds. It’s considered the most common type of glaucoma and is caused by inherited abnormalities in the eye structure. 

In dog breeds with primary glaucoma, the drainage angle is too narrow or malformed. This abnormality limits the amount of fluid that can be drained from the eye, resulting in a slow and gradual buildup of pressure.

Common breeds affected by primary glaucoma include:

• Cocker Spaniels

• Basset Hounds

• Beagles

• Boston Terriers

• Siberian Huskies

Secondary

Secondary glaucoma in dogs is a type caused by other health issues and eye conditions. In many cases, only one eye is affected. Here are the common causes:

• Uveitis. The inflammation results in a buildup of cells, proteins, and other debris, causing a clog that hinders the drainage of fluid from the eye. 

• Lenx Luxation. The lens becomes loose and dislocated, shifting forward or backward. This can physically obstruct fluid flow and block drainage, causing acute glaucoma in dogs, a painful medical emergency.

• Cataracts. Advanced cataracts can trigger blockage through lens-induced uveitis or the dissolution of cataracts. These conditions cause physical obstruction, which prevents fluid from the eye from draining properly. 

• Intraocular Tumors. Tumors that grow within the eye can physically obstruct the iridocorneal angle, the pathway through which fluid drains. 

• Eye Trauma. Injuries and blunt force to the eye can damage the trabecular meshwork, the drainage system of the eyes. Other results of injuries can include inflammation, lens displacement, intraocular bleeding, and cataracts, all of which can lead to glaucoma.

• Intraocular Bleeding. When bleeding happens within the eye, the blood can clot, leading to an obstructed flow of fluid.

What are the Signs of Glaucoma in Dogs?

If your dog shows any of the signs of glaucoma, it’s important to bring them to the clinic for urgent care.

• Squinting or blinking more often. Dogs may squint because of mild eye pain as pressure begins to increase. It’s often mistaken for dust or dry eye, but it can be the first warning sign.

• Cloudy or bluish cornea. Affected dogs may have a foggy cornea due to the buildup of fluid. This can indicate rising intraocular pressure. 

• Redness in the white part of the eye. The blood vessels can swell, leading to a bloodshot appearance of the eye.

• Hesitation in dim light. Dogs may start bumping into furniture or have visible trouble navigating. They might prefer rooms with dim lighting.

• Teary eye. In some cases, your dog’s eyes will start to tear and show discharge.

• Unequal pupil sizes. Pressure changes can affect how the pupil responds to light, leading to clear asymmetry. 

• Bulging or enlarged eye. Due to the increased pressure, the eye will expand, resulting in a noticeable increase in size. 

• Severe eye pain. Dogs with glaucoma may seem withdrawn, lethargic, or irritable. Some dogs will try to rub or paw at their eyes, while others may feel less interest in eating and playing.