Corneal Ulcers in Dogs: Causes, Symptoms & Treatment

While corneal ulcers in dogs are more common among certain breeds, all dogs are at risk of developing them. Read on to learn about the diagnosis and treatment of a dog with a corneal ulcer, plus get tips for prevention.

What Is a Corneal Ulcer?

The cornea is the clear outermost layer of the front of the eye that helps contain the eye's jelly-like filling. The cornea is made up of tissues that are tough enough to withstand light bumps and minor injuries, but delicate enough to let light pass through unimpeded for terrific eyesight.

The cornea is covered by a thin layer of cells called the corneal epithelium. When this surface layer is breached and cells here are damaged or dislodged, it results in an injury called a corneal ulcer.

Causes of Corneal Ulcers in Dogs

The superficial layer of the cornea can be damaged as a result of the following:

• Chemical burns: From shampoo, skin medicine, ear cleaner, etc.
• Scratches: From accidental self-trauma, roughhousing or a fight
• Blunt trauma: From a car accident or running into an object, for example
• Penetrating injuries: From sticks, sharp toys, claws or teeth
• Rubbing: From foreign bodies under the eyelid, dry eye, lid problems or an itchy eye

Corneal ulcers in dogs can also develop when the corneal epithelium becomes diseased or infected. Minor injuries can lead to complications if they get infected. Primary infections of an otherwise healthy eye can also happen with some aggressive viruses and fungi.

Dogs can also develop a corneal ulcer for an unknown reason. In these cases, the condition is called indolent ulceration or spontaneous chronic corneal epithelial defects. This mostly occurs in dogs older than 6 years old.

Signs of Corneal Ulcers in Dogs

The most common signs of corneal ulcers in dogs include:

• Blinking excessively or shutting the affected eye
• Significant tearing or discharge from the eye
• Redness and/or swelling of the tissues surrounding the eye
• Poor appetite
• Hiding
• Pawing or rubbing the eye, among other abnormal behaviors

Corneal ulcers are fairly easy to diagnose by a veterinarian. Some dogs will have obvious changes to the surface of the eye. Most, however, will need a simple diagnostic test involving fluorescein dye to stain the cornea, thereby making it easier to see where there is damage.

Risk Factors

Corneal ulcers can affect dogs of any breed at any life stage. However, young dogs are generally more likely to suffer a trauma that causes a corneal ulcer, since they tend to get themselves into more trouble.

Dogs born with bulging eyes, dry eyes or an eyelid shape or structure that makes them prone to dry eyes or rubbing injuries — as seen in bloodhounds and Shar-Peis — predisposes them to corneal ulcers. Indolent ulcers are most often seen in golden retrievers and boxers.

Most genetic conditions that predispose a dog to corneal ulcers come to the surface in middle-aged or senior dogs.