Cherry Eye in Dogs and Cats: Diagnosis and Treatment
Unlike humans (who only have two), 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 diagonally. It serves to act as another layer of protection if the upper and lower lids are unable to blink and to produce up to 30% of tear production for the eye.
The tear gland of the third eyelid is held in place by tissue fibers, but some individuals have weaker fibers than they should so the gland protrudes. This protrusion is called a cherry eye. In the smaller breeds — especially Boston terriers, cocker spaniels, bulldogs and beagles — the gland of the third eyelid is not strongly held in place for genetic reasons. The gland prolapses out to where the owner notices it as a reddened mass. Out of its normal position, the gland does not circulate blood properly, may swell, and, most importantly, may not produce tears normally.
By far the best treatment for cherry eye is replacing the gland back into its proper location. It is important to note that an older technique involved removal of the affected gland but this is no longer recommended because it often leads to Dry Eye (also known as keratoconjunctivitis sicca or KCS). If your dog has cherry eye in 1 or both eyes it is strongly recommended to have it surgically replaced using one or a combination of the following procedures:
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 be aware of the following possibilities:
- If the stitch unties, the surface of the eye could become scratched by the suture. If this occurs, the eye will become suddenly painful and the suture thread may be visible. The suture can be removed and the problem solved.
- The tuck may not be anchored well enough to hold permanently. In fact, this surgery is notorious for this type of failure and frequently a second or even third tuck is needed.
- The stitch needle may break off in the periosteum which requires a more invasive surgery to retrieve.
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. Complications may include:
- Inflammation or swelling as the stitches dissolve.
- Inadequate tightening of the tissue gap may lead to recurrence of the cherry eye.
- Failure of the stitches to hold and associated discomfort. Loose stitches could injure the eye depending on the type of suture used.
Sometimes both surgical techniques are used in the same eye to achieve a good replacement. Harmful complications from cherry eye surgery are unusual but recurrence of the cherry eye can happen. If it recurs, it is important to let your veterinarian know ASAP so that a second surgery can be planned.
Expect some postoperative swelling after cherry eye repair, but this should resolve and the eye should be comfortable and normal in appearance after about a week. If the eye appears suddenly painful or unusual in appearance, have it 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.