Glaucoma in dogs

Glaucoma is a condition of the eye that can affect a wide range of different animals, including cats, dogs and people. Left unchecked, glaucoma can lead to eventual blindness, which is irreversible, and so it is important for all dog owners to learn a little bit about the condition, its symptoms, and what it means for affected dogs. In this article, we will provide a basic introduction to glaucoma in dogs, including the causes, symptoms and treatment. Read on to learn more.

What is glaucoma?

Glaucoma is one of the most common canine eye conditions, and is all related to the level of pressure within the eye itself. The shape and normal structure of the eye depends on fluid at the front of the eye to keep everything where it should be, and this is referred to as the intra-ocular pressure, or level of pressure within the eye. The fluid itself is called aqueous humour.

When the pressure within the eye itself is too high, it can lead to damage to various different parts of the eye, including the optic nerve and the retina, both of which are essential for normal vision-and this is what we refer to as glaucoma.

Glaucoma usually occurs when there is too much aqueous humour present in the eye, which in turn happens when the eye is unable to drain off any excess fluid in the normal way. This additional fluid leads to the pressure in the eye rising, which in turn leads to it pressing on the other parts of the eye so that they are unable to function properly, and may become permanently damaged.

Different types of glaucoma

Glaucoma comes in two different forms, which are referred to primary and secondary.

Primary glaucoma

Primary glaucoma happens because the dog has an unavoidable predisposition to the condition, which is often due to hereditary causes, or may be due to their physiology, such as if the dog has a particularly flattened face, as is the case with some brachycephalic dog breeds. This normally means that in dogs suffering from primary glaucoma, the drainage channels are either too narrow or at the wrong angle to allow for normal drainage.

Secondary glaucoma

Secondary glaucoma refers to glaucoma that is caused as a secondary effect of another health condition, such as damage to the eye due to injury, or an infection or illness that causes the eyes to become inflamed or infected and so, affects the eye’s natural drainage.

What sort of dogs can be affected by the condition?

If glaucoma occurs because of an injury or as a side effect of another condition that has affected the eye (secondary glaucoma) any breed or type of dog may be affected. However, when it comes to primary glaucoma, this is more prevalent within certain breeds and types of dogs than others, due to either their standard conformation or because they have inherited a predisposition to the condition through their genes.

Some of the breeds that secondary glaucoma most commonly affect include the Pug, Siberian husky and the Poodle.

How would I know if my dog had glaucoma?

There are a reasonably broad number of different symptoms that can present in canine glaucoma, and not all dogs will exhibit all of them, or the same combination of symptoms. Additionally, some of the symptoms can also be seen in certain other canine eye conditions too, so it is important that you take your dog to the vet as soon as you spot a problem, to get a formal diagnosis.

Some of the symptoms that you might see include:

• Excessive blinking.
• The eyeball sinking into the socket.
• Pupils that are overly large, and/or not responsive to changes in the light, or that are overly small and constricted.
• A red, irritated appearance to the eye.
• Clouding of the lens.
• Loss of vision.
• Sticky, gummy eyes that may be hard to open and close.
• Debris or particles visible on the lens, which cannot be removed.

What can be done about it?

Depending on whether the dog is suffering from primary or secondary glaucoma and the effect that it is having, there are various different methods of treating the condition.

Draining the excessive fluid in the eye and using cryotherapy to stop the eyes from producing too much fluid in the future is one approach, and in some cases of secondary glaucoma, once the initial problem that led to the condition has been resolved, the glaucoma will become easier to resolve too.

In chronic cases of glaucoma and those that are very advanced, it may be necessary to remove the eye itself, with the lids being sealed over the space or in some cases, a false orb being used to fill it. The need for removal of the eye can in some cases be prevented by early intervention, which means that it is really important to seek diagnosis and treatment as soon as possible, to give your dog the best possible chance of retaining their vision.