Corneal ulcers in dogs

Content by Dr Siân Burwood MA VetMB MRCVS

Corneal ulcers in dogs are defects in the top protective layer of the eye. The cornea is the clear layer that keeps the eye ball as a ball, providing structure and protection from the outside world.

Ulcers are usually caused by trauma to the eye, but are more likely in dogs with certain eye shapes or underlying conditions. Corneal ulcers are very painful, can take a long time to treat and can even result in loss of sight or loss of the eye itself. But if treated early and aggressively, a full recovery can be made.

• Corneal ulcers are painful damage to the clear protective front layer of the eye
• They’re usually caused by injury, but are more likely in dogs with flat faces or underlying medical conditions that make rubbing the face more likely
• Any dog screwing its eye shut should be seen by a vet as an emergency
• Treatment involves pain relief, antibiotic and lubricant drops and stopping the dog causing further damage
• Regular rechecks with your vet are needed to make sure that healing is progressing as it should, as worsening ulcers can cause permanent eye damage

The cornea is a clear layer of cells over the whole front of the eye. It keeps the other eye structures together as an eyeball, helps to focus light through the eye, and also provides protection from bacteria.

Corneal ulcers are damage to this part of the eye, and are usually caused by an injury – either from the dog rubbing the eye, or from some foreign material getting into it.

Some dogs are more prone to ulcers than others because they have underlying eye issues (such as dry eye) that make damage more likely. Alternatively they may have genetic issues with their face shape or corneal healing that make repair much harder.

Any breed can be affected by corneal ulcers, especially those that happen through injury. These can happen at play, or from running around in a garden or field.

Brachycephalic (flat faced) dogs are the most likely to get corneal ulcers because they have wide bulging eyes, plus less nose to get in the way of something getting in the eye.

This means the following get corneal ulcers more frequently:

• Pugs
• English and French Bulldogs
• Boxers
• Boston Terriers

For many of these breeds, they also have an issue with how the cornea repairs. This means it can take much longer for their ulcers to heal.

Dogs who have allergic skin disease are more likely to get corneal ulcers if they aren’t well controlled, because they rub their faces more. This includes many of the above breeds, but also Staffordshire Bull Terriers and West Highland White Terriers.

Dogs who are prone to ‘dry eye’ (keratoconjunctivitis sicca) are also more at risk of corneal ulcers because their eyes feel itchy. This includes many of the above breeds, but especially Shih Tzus.

The main symptom of a corneal ulcer is a dog who is screwing up one eye, either on and off or keeping it permanently shut. This is a sign of eye pain and an indication to get to your vet straight away. You’re unlikely to be able to see the ulcer on your own.

Your dog may also rub at the eye, have some weeping from the eye, or seem generally distressed. Other dogs show no eye signs at all but become very depressed with the pain.

Diagnosis

To see a corneal ulcer, your vet will need to apply an orange dye, which then fluoresces green under a UV torch. This will show your vet how big and how deep the ulcer is. Some vets will also have access to a ‘slit lamp’ which allows them to see inside the eyeball itself to look for other signs of damage.

As corneal ulcers are very painful, your vet may need to apply local anaesthetic to the eye before they are able to look. Some dogs even need to be examined under sedation.

Treatment of corneal ulcers needs to be consistent and aggressive, and can take a long time even when instructions are followed. Your vet cannot heal the ulcer, but needs to create the right environment for the body to be able to heal itself through:

• Pain relief
• Antibiotic eye drops
• Lubricant eye drops
• Preventing further damage with use of a buster collar or contact lens

You’ll need to see your vet for regular rechecks to check the ulcer is getting smaller rather than bigger, and to check for signs of healing.

If the ulcer isn’t healing as expected, your vet may recommend the ulcer is ‘debrided’ under sedation. This is where dead corneal cells are rubbed away and healing stimulated.

In the most severe cases, your vet may need to suture the third eyelid shut over the ulcer, or refer you to an ophthalmologist for a graft (which uses the body’s own eye tissue like a plaster).

Prognosis

Corneal ulcers should always be taken seriously because they cause a lot of pain, as well as risking losing sight in that eye or even rupturing the eyeball if the ulcer gets too deep. With early and consistent treatment, however, many ulcers will eventually heal – and even the most serious ones can have good outcomes with suitable treatment from a specialist.

“Like most vets, I’m always sad to diagnose a corneal ulcer because I know just how painful they can be, and just how long they can take to treat. What I’ve found is that by helping owners understand that our job is to help the body heal itself through consistent treatment, the vast majority of cases can be treated effectively.

“In at-risk breeds such as Pugs and Boxers, even the most dedicated owners can still struggle to get an ulcer healed, and being able to refer them to an ophthalmologist for more specialist help is invaluable.”

Dr Siân Burwood, MA VetMB MRCVS

When getting a quote for Petgevity Lifetime Plus insurance, tell us about your dog’s corneal ulcers, plus any other conditions they’ve had in the past two years*.

It’s important to list your dog’s conditions when taking out pet insurance, so you increase your chances of a successful claim in future.  

Find out more about our dog insurance for pre-existing medical conditions.