Glaucoma in dogs

Glaucoma in dogs is a complex disease that can be very painful and blinding; especially if left untreated. So, how do dogs get glaucoma, what are the symptoms to watch out for, how do you know if your dog is affected, which breed types are most at risk and what are the treatment options?

What is glaucoma?

Glaucoma is a painful condition that’s caused by a build-up of pressure inside the eye. This increased pressure can occur if the eye isn’t able to properly drain away enough of the fluid that’s made inside it. The rise in pressure (referred to as intraocular pressure) can become so high that it causes damage to other tissues within the eye, leading to permanent vision impairment and blindness.

Are there different types of glaucoma?

There are several different types of glaucoma:

• Primary open angle glaucoma (POAG)
• Primary closed angle glaucoma (PCAG)
• Congenital glaucoma
• Secondary glaucoma

Primary glaucoma is the most common type that affects dogs, and is broken down into open angled, or closed angled (POAG or PCAG). The term ‘angle’ in POAG and PCAG describes a structure within the eye called the iridocorneal angle, which allows fluid to drain away from the eye.  

In PCAG, the iridocorneal angle is closed, affecting the amount of fluid that can drain away.

In POAG, the angle is open, but there might be other problems that stop the fluid from draining.

PCAG is more common than POAG in dogs. These two types of glaucoma have a hereditary component in some breeds, but only POAG (in some breeds) has a DNA test available. More information about pre-breeding checks can be found below.

Two other types of glaucoma can affect dogs, but these are less common. These include:

• Congenital glaucoma, which is present from birth
• Secondary glaucoma, which develops because of another eye disease, such as cataracts, cancer, or uveitis

How can I tell if my dog has glaucoma?

Glaucoma can be a very painful disease and may cause symptoms such as:

• Depression or being withdrawn
• Squinting
• Excessive blinking
• Scratching or rubbing their eyes
• Weepy eyes
• Pupils being different sizes
• Eyes looking red or sore
• Eyes looking cloudy
• Vision problems

In severe cases, a dog may go completely blind.

What age does glaucoma develop?

Most forms of glaucoma begin during middle to late age in dogs, but some breeds may be affected earlier. How quickly glaucoma develops differs depending on the type, with some forms progressing over several years, and others occurring more quickly.

How is glaucoma inherited?

We don’t fully understand how PCAG is inherited, but it’s probably very complicated, involving many different genes and influenced by other lifestyle factors. However, some genetic mutations have been associated with POAG in several breeds, and a DNA test can be used for breeds affected by these types.

What breeds are affected by glaucoma?

Breeds that can be affected by PCAG include:

• Basset Hounds
• Border Collies
• Cocker Spaniels
• Dandie Dinmonts
• English Springer Spaniels
• Flat Coated Retrievers
• Golden Retrievers
• Hungarian Vizslas
• Japanese Shiba Inus
• Leonbergers
• Siberian Huskies
• Welsh Springer Spaniels

Breeds that can be affected by POAG include:

• Basset Hounds
• Petit Basset Griffon Vendeen
• Shar Pei

How do I test for glaucoma?

Thankfully, there’s a screening scheme available that checks for signs of abnormality (known as goniodysgenesis) in the eye, which helps us identify the risk of a dog developing glaucoma. The BVA/KC/ISDS Eye Scheme has a number of specialist ophthalmologists who can examine your dog through a technique called gonioscopy, which looks at the degree of abnormality in a tissue called the pectinate ligament, part of the iridocorneal angle. Dogs are then graded depending on how mild or severe the eye is affected.

More information about the screening scheme can be found here.

What treatment options are available for glaucoma?

The treatment options available to you depend on how quickly your dog’s glaucoma is identified. If the intraocular pressure is not reduced quickly, the eye can be damaged irreversibly. Therefore, if you notice any signs linked to glaucoma, it’s important to get your dog seen by a vet as quickly as possible. Your vet is likely to prescribe medication to reduce pain and discomfort, and also medication that decreases the amount of fluid the eye is producing, as well as increasing the amount of drainage to relieve pressure build-up. Similarly, if there is another condition causing glaucoma, it’s important to get your dog seen quickly by a vet to get this under control.

These treatment options may be tailored to be long-term or short-term, depending on the type and severity of your dog’s condition. If your dog’s glaucoma can’t be controlled through medication, your vet may suggest surgery to physically alleviate the pressure within the eye. In some severe instances, a vet may recommend complete removal of the eye (called enucleation). Many dogs survive well without one or both eyes, but it is important to consider any implications this could have on your dog’s quality of life, and how well you and your vet feels they will adapt to being partially or completely blind.

Can glaucoma be cured?

Ultimately, unless the glaucoma has developed due to another condition, it cannot be cured and requires long-term management to prevent further damage to the eye.

Dogs can live with glaucoma and be pain-free if it is well managed, but it is important to discuss the long-term prognosis and treatment costs with your vet and insurance provider to ensure you’re covered and prepared for any long-term costs.

What can I do to prevent glaucoma?

Unfortunately, as the inheritance and development of glaucoma is complex, there is no one factor that will reduce risk of glaucoma. However, by testing and only breeding from dogs that have either no known risk or only a mild risk of disease, breeders can reduce the risk of producing affected puppies.

Gonioscopy testing allows you to test your dog throughout their lifetime to determine whether they’re showing any progression in pressure build-up, which helps you discuss early treatment options with your vet before the disease takes hold.

Can I breed from my dog if they have glaucoma?

Because glaucoma is largely thought to be an inherited condition, it’s possible that breeding from an affected dog could pass this disease on to puppies. Given that it is potentially a very painful and debilitating disease, we do not recommend that you breed from a dog that has been affected by glaucoma.

Where can I find further support and resources?

The BVA/KC/ISDS Eye Scheme have a group of specialist ophthalmologists who can support you with veterinary advice, should your dog be diagnosed as affected by glaucoma when examined.

If your dog has glaucoma, and you would like advice from owners who have had similar experiences, we would recommend contacting your breed club or Breed Health Co-ordinator, as they may be able to share their knowledge with you and put you in touch with other owners who have had dogs affected by the condition.

Can I contribute to any research?

It is worth checking our research page here to see current research projects that apply to your breed.