Wednesday, December 4, 2013

Cherry Eye and Pets

Cherry eye, also called prolapse nictitans gland (tear gland of the third eyelid), is a hereditary condition that affects various dog breeds and a few cat breeds. Pet owners may notice redness and inflammation in one of both of their pet’s eyes—but don’t chalk this up to simple irritation. Cherry eye can cause long-term issues if overlooked.
The good news: Modern medicine offers a surgical remedy that corrects the problem. Dr. Jennifer Hawkins, a contributing veterinarian for the VPI Pet HealthZone, shares her experience about treating the condition.

What is Cherry Eye?

“Cherry eye” is a condition that affects many dogs in which the tear-producing gland that is present under the lower eyelid pops out, or prolapses.

This prolapsed gland is easily seen as a bulging red mass protruding from the third eyelid (you know, that pink veil the sits at the inside corner of your dog's eye). In some dogs, this gland of the third eyelid simply isn’t held down very well into its normal position. Dogs that have one gland prolapse may later have prolapse of the gland of the opposite eye.

Which Dog Breeds Are Prone to Cherry Eye?

The genetics are complex but it is generally accepted that cherry eye is a hereditary condition for which some dog breeds may be predisposed.
The facial conformation, or shape, is also a factor as breeds with a short muzzle are more prone to developing this condition. Cherry eye is more common in boxers, bulldogs, beagles, basset hounds, pugs, Boston terriers and cocker spaniels to name a few.
Cats very rarely develop cherry eye, but the condition has been seen in Burmese and Bombay cats. However, technically, any breed can develop cherry eye.


Cherry eye diagram
When I first graduated from veterinary school, I worked in a practice with two other veterinarians. One of the patients on the surgery schedule was a dachshund named Mimi, who was scheduled for cherry eye repair.
I had learned to surgically correct this protruding tear gland that affects many dogs, but one of the veterinarians was of the opinion that the entire gland should be removed. It sparked much debate among the three of us—no one was satisfied until we spoke to a boarded veterinary ophthalmologist.
That day, many years ago (we won’t divulge how many), myself and the other two doctors were able to lay our dispute to rest. The ophthalmologist informed us that indeed, though it was once common to remove these tear glands in the event of cherry eye, it had since been determined how very important it was to preserve the gland. Thus the gland should always be replaced into its natural position under the eyelid.

Long-Term Effect 

Some pet owners elect to not address the cherry eye as the problem appears only cosmetic. However, inflammation of the prolapsed tear producing gland and decreased blood flow to the gland caused by its abnormal anatomic position eventually lead to decreased tear production and yet another condition, keratoconjunctivitis sicca (KCS) or “dry eye.”
Decreased production of the aqueous portion of the tears causes the eye to compensate by increasing the mucoid portion of the tears. This leads to the affected eye becoming gummy and gooey while also negatively impacting the corneal health (the cornea is the clear front layer of the eye).
As a result, the cornea eventually becomes black due to lack of proper lubrication. This black, or melanotic, cornea does affect vision relative to the severity of the melanosis.
Dry eye requires lifelong eye medications, not artificial tears, but prescription medications. Artificial tears require application every two hours to be remotely effective and are thus a very impractical treatment choice.

Potential Complications of Surgery 

There are a multitude of surgical techniques to repair cherry eye, all of them effective. However, it is still possible for the gland to prolapse again and sometimes require another surgery.
Also, the opposite gland may prolapse thus requiring surgery. Occasionally, a small piece of suture material may loosen causing eye irritation. Sometimes this is treated with eye medication, other times a second surgery to remove the offending piece of suture material is needed.
As it turns out, I was beginning my career during a time when the current paradigm with regards to cherry eye treatment was changing due to a more thorough understanding of the importance of this gland. I am pleased to say that Mimi had surgery to replace the tear gland back under the third eyelid and had a great recovery.

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