Cherry Eye in Dogs and Cats: Diagnosis and Treatment
Dogs and cats have three eyelids. The third eyelid, technically called the nictitans or nictating membrane, arises from the inner corner of the eye and covers the eye in a diagonal plane. It serves 2 functions. First, it can blink to cover and protect the eye when the upper and lower eyelids either can’t blink because of disease or when they can’t blink fast enough (the third eyelid actually blinks faster than the other two!). The second function is tear production. The third eyelid houses a tear gland that produced up to 30% of the entire tear production for the eye.
This gland should be help tightly in place but some breeds are genetically predisposed to having third eyelid glands that do not stay in place. These breeds include Boston terriers, cocker spaniels, bulldogs, beagles and other brachycephalic breeds. When the gland does not stay in place, it prolapses upwards (towards the upper eyelid) and swells. Many owners see this as only a cosmetic problem but the truth is much worse. Glands that sit prolapsed out of the normal position inhibit normal third eyelid function because the gland is kept from moving and protecting the eye the way it should. Tear production can also be affected which can lead to “dry eye”, also known as Keratoconjunctivitis sicca or KCS.
Treatment
By far the most appropriate treatment for cherry eye is replacing the gland back into its normal location. There are 2 appropriate ways to replace the gland back into a normal position.
Periorbital Tacking
In this procedure, a single stitch is placed in the 3rd eyelid and anchored to the covering of the bone in the eye socket called the periosteum. This will draw the gland back where it belongs. It is important to note that while this procedure allows normal tear production from the gland of the third eyelid, the third eyelid will no longer be able to move and therefore loses its protective function. Complications are uncommon but include:
- The suture rubbing on the surface of the eye if it becomes untied or malpositioned
- Failure because the suture is unable to hold the gland in place
- The suture needle breaking off in the periosteum during the procedure
Each of these complications can be repaired, but can require additional surgery.
Pocket Technique
In this procedure, an incision is made on either side of the affected gland. The incisions are then sewn together to create a “pocket” that holds the gland in a normal position. This technique allows for normal tear production and normal third eyelid movement and function. It is a more technically demanding procedure than the tacking procedure.. Complications may include:
- Inflammation or swelling as the sutures dissolve
- Suture rubbing on the surface of the eye if they become untied
- Failure (re-prolapse)
Each of these complications can be repaired, but can require additional surgery.
Sometimes both surgical techniques need to be utilized in the same eye to achieve a good replacement.
Post-op expectations include some postoperative swelling and discharge from the eye for 5-7 days. Most eyes look normal by 14 days after surgery, though a small percentage can take months to return to normal. If the eye appears suddenly painful or unusual in appearance, it should be rechecked as soon as possible.
Several of the doctors at The Pet Hospitals perform these procedures and any of our doctors can consult with you about what treatment is best for your individual pet should it be affected by cherry eye in one or both eyes.
