Pet Health Library

Background

To understand what a corneal ulcer is, it’s important to have a basic understanding of the anatomy of the eye. The eye has three layers, and the outermost layer is susceptible to minor abrasions. These abrasions are often small enough to go unnoticed, but the longer they go untreated, the worse they can become.

If an abrasion deepens into the second layer of the eye, an ulcer can form. However, ulcers don’t only result from abrasions — they can also develop from serious eye trauma, bacterial infections, or viral infections. Corneal ulcers may also be a side effect of other diseases such as Cushing’s disease, diabetes mellitus, keratoconjunctivitis sicca (dry eye), or hyperthyroidism.

Corneal ulcers are more common in certain dog breeds, including Airedales, Cocker Spaniels, Bearded Collies, Cavalier King Charles Spaniels, Samoyeds, Weimaraners, and brachycephalic breeds such as Pugs and Boxers.

A corneal ulcer can be incredibly painful for your dog and, if left untreated, may affect the third layer of the eye, resulting in permanent blindness.

Signs

• Increased tearing
• Colored discharge
• Cloudiness
• Redness
• Squinting

If you recognize any of these signs, contact your veterinarian so they can properly diagnose your dog.

Diagnosis

Large ulcers can sometimes be visible and relatively easy to diagnose. To confirm a corneal ulcer, your veterinarian may perform a painless procedure called fluorescein staining. In this test, a liquid dye is placed into the affected eye. Any damaged tissue or ulcerated area will absorb the dye and appear green under a special light. This helps your vet confirm the presence and severity of the ulcer.

Your vet may also perform additional tests to rule out underlying issues that could be contributing to the ulcer. Urine, blood, and skin samples may be collected to help identify the cause. If an underlying condition is found, your veterinarian will discuss the appropriate treatment plan.

Treatment

Because corneal ulcers are painful, your dog may try to scratch or rub the affected eye, which can worsen the injury. To prevent this, your veterinarian may prescribe pain medication in the form of eye drops. Due to a dog’s anatomy, some of the medication may drain into the throat, which can cause drooling or pawing at the mouth afterward. This reaction is normal and simply due to the bitter taste of the medicine.

Your veterinarian will also likely recommend an Elizabethan collar (e-collar) to prevent further scratching.

The primary goals of treatment are to reduce pain and prevent additional damage so the eye can heal. You may notice red streaks on your dog’s eye during recovery — this is normal and indicates that new blood vessels are forming to aid the healing process.

If the ulcer does not heal or worsens, surgery may be recommended. In severe cases, especially when there is risk of blindness or chronic pain, enucleation (eye removal) may be necessary to ensure your dog’s comfort and quality of life. This procedure requires anesthesia, so your dog will first undergo a full physical exam to confirm they can tolerate it. Recovery usually takes a few weeks, during which your dog will need to continue wearing an e-collar until the area is fully healed.

To further prevent scratching, your vet will likely give your dog an e-collar.

The focus of the treatment is to reduce pain and prevent further damage so that the eye can repair itself. You may start to notice red streaks on your dog’s eye. This is normal. Your dog’s body is supplying new blood to the injured area to help the healing process.

In the event that there is no improvement or healing, your vet may recommend surgery. Because a corneal ulcer is painful and can lead to blindness, the eye may be removed (enucleation) to ensure the best quality of life for your dog. This process will require sedation, so your dog will need a full physical exam to ensure that he can tolerate anesthesia. The recovery from enucleation can take a few weeks and will also require an e-collar until healing is complete.

Prevention

Unfortunately, there’s no guaranteed way to prevent corneal ulcers. If your dog belongs to one of the at-risk breeds listed above, monitor their eyes closely for any of the signs mentioned. If you notice anything unusual about your dog’s eyes or suspect a problem, contact your veterinarian promptly.