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Corneal Ulcers in Dogs

Corneal ulcers are wounds to the outer layer of the eye.

The cornea is the outermost layer of the front of the eye. It protects the inner structures of the eye and allows light in to be processed for vision. The cornea is dome-shaped and transparent.

What Is a Corneal Ulcer?

A corneal ulcer is a wound or break in the outermost layer of the cornea. It is painful to the dog.

Causes of Canine Corneal Ulcers

Eye ulcers in dogs may be caused by a wound to the eye. This could be a scratch, abrasion, puncture, or other trauma.

Ulcers may be self-inflicted if the dog is rubbing his eye for any reason, including allergies. An ulcer may also be secondary to another eye condition such as KCS or entropion.

An eyelash or other foreign material may be stuck on the eye's surface or under the eyelid. This foreign object then may continually rub on the cornea, causing an ulcer.

Corneal ulcers are more common in dogs with flat faces and protuberant eyes because the eyes are less protected and more easily scratched. Some dog breeds that are more prone to corneal ulcers for this reason include pugs, boxers, Pekinese, and Boston terriers.

Signs of Eye Ulcer in Dogs

Dogs with corneal ulcers usually show some or all of the following signs:

  • Squinting of the affected eye.
  • Rubbing the eye on external surfaces or pawing at it.
  • Redness of the whites of the eye.
  • Ocular drainage from the affected eye.
  • Sensitivity of the eye to light.

Diagnosis of Canine Corneal Ulcers

Eye ulcers in dogs are diagnosed through examination of the eye by a veterinarian. Some ulcers are visible when looking at the eye directly or through an ophthalmoscope. Others are more subtle and can be seen only after a special dye (fluorescein) has been placed on the eye. The dye is not taken up by the normal epithelial cells of the cornea, but it is held by the damaged portion, making an ulcer more visible.

Some general veterinary practitioners and veterinary ophthalmologists may also examine the dog's eye with a slit lamp, which is an instrument that magnifies the doctor's visualization of the cornea greatly, so it can be examined carefully.

Other tests may also be done on the eye if the veterinarian suspects another eye problem may have led to the corneal ulcer. For instance, tear production may be tested to check for KCS.

If a corneal ulcer becomes complicated, meaning it doesn't heal quickly or well with initial treatment, samples of the area may be collected for bacterial culture or viral testing.

Treatment of Corneal Ulcers in Dogs

Uncomplicated, simple corneal ulcers are usually treated with antibiotic eye drops to help prevent infection and an Elizabethan collar to prevent your dog from further traumatizing the eye by rubbing it.

Do not place eye drops you have at home in your dog's eye without first speaking to your veterinarian. Some types of eye drops, such as those containing steroids, can greatly worsen a corneal ulcer.

Complicated ulcers or those that don't respond well to treatment may need a variety of other therapies. Some possibilities include:

  • Conjunctival flap therapy. This treatment involves suturing the dog's third eyelid, located under the lower eyelid, to the inside of the upper eyelid, creating a cover for the cornea. This protects the wound while it heals and provides it with moisture from the third eyelid.
  • Keratotomy. This is a surgery during which the cornea involved in the ulcer is pierced or cut to encourage a new layer of epithelium to attach in that area.
  • Soft contact lenses. Inserting a soft contact lens over the corneal ulcer can help protect it so it can heal.
  • Corneal transplant. This is a treatment that requires a specialty veterinary clinic to perform.

Indolent Ulcers

Indolent or refractory ulcers, also known as Boxer ulcers because that breed is commonly affected by them, are non-healing or recurrent eye ulcers. They are most common in older dogs, and they often take months to heal. These ulcers usually need more than basic treatment to heal. Keratotomy and conjunctival flap therapy are often utilized to help these dogs.

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