Pets/Dr. Pukay: Several treatment options for corneal ulcers in dogs - Ottawa Citizen

Question: My eight-year-old boxer has recently been diagnosed with a corneal ulcer. We have been putting eye drops in his eye (Ciloxan) up to eight times daily as per instructions. If the ulcer does not heal, we were informed that the ulcer would have to be scraped and the eyelid temporarily closed surgically. Is there another option to surgery (i.e. laser)? He has had surgery in the past (on his jaw for recurrent locking and a knee repair). We would prefer not to put him through more surgery both for his sake and ours.

Answer: The normal cornea is a clear, transparent membrane covering the eye that is composed of several layers. These layers have a remarkable ability to regenerate themselves when damaged and healing usually only takes about six or seven days after injury.

However, if the injury to the cornea is persistent and chronic, healing may be delayed or not occur at all. These kinds of ulcers are referred to as indolent ulcers, but can also go by other names such as chronic epithelial erosion, refractory superficial ulcers and, because there is a genetic predisposition in middle-aged to older boxers, boxer ulcer. However, all breeds of dogs, especially older dogs, can get an indolent ulcer.

If the cornea is ulcerated, that eye becomes very sensitive to light and very painful and, because of this, the eyelids often become spastic (squinting) and there is tearing.

The diagnosis of a corneal ulcer is simple and straightforward: the veterinarian applies a special green fluorescent stain to the eye and, if there is an ulcer present, the ulcer stains a granny-apple green. It is important that the veterinarian determines the cause of the ulcer so he or she will do other tests, including a test to check tear production (Schirmer Tear Test) because inadequate tear production is one of the leading causes of corneal ulceration.

There are several treatment options but laser surgery is not one of them. Usually, treatment starts with antibiotic drops, just as your veterinarian has prescribed. If this fails to heal the ulcer, the next step is to debride the ulcer margins (i.e. removal of dead corneal tissue) under a topical anesthetic using a sterile cotton-tipped applicator. This may be done several times, if necessary.

If this fails to heal the ulcer, it may need to be "scraped," i.e. a linear or grid keratectomy is performed whereby a small gauge needle is used to score the cornea (i.e. make small parallel linear incisions) to promote healing. Using this technique, healing occurs in 80 to 85 per cent of patients within 10 to 14 days. This can usually be done under a topical anesthetic with or without sedation.

Finally, if this treatment proves ineffective or the ulcer is extremely advanced, a surgical procedure known as a superficial keratectomy may be required, and this does require a general anesthetic. This surgery is very invasive and also expensive but it is also the most successful. The damaged portion of the cornea is excised surgically and a third eyelid flap is sutured into place to protect the eye post-operatively. The success rate is usually 100 per cent and healing only takes one week.

Discuss your concerns with your veterinarian and the alternatives available to you. If you feel a second opinion may be helpful, ask your veterinarian to refer you to a board-certified veterinary ophthalmologist.

Dr. Bernhard Pukay is an Ottawa veterinarian. Address letters to Pet Care, Ottawa Citizen, P.O. Box 5020, Ottawa K2C 3M4. Email: pets@ottawacitizen.com. Due to the volume of mail, not all letters can be answered.

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