|DEFINITION: Cherry eye is
clinically defined as a prolapsed gland of the
third eyelid. The term cherry eye was coined
because the prolapsed gland looks like a cherry
located near the inner corner of the eye.
BREED AND AGE: Cherry eye can occur in many breeds of dogs but is most common in young bulldogs. Although the problem can occur at any age, it is most common in animals 2 years of age or younger and can be unilateral or bilateral at initial presentation. Although the precise mechanism by which cherry eye is inherited is unknown, the breed predisposition implies some type of genetic mechanism.
PATHOPHYSIOLOGY: The anatomical structures that anchor the gland of the third eyelid in its normal position and the pathogenesis of their failure are poorly understood. The gland is classified as seromucoid in dogs and contributes an estimated 30% to 57% to aqueous tear production. Partial or total removal of gland predisposes the patient to KCS (Kerato-conjunctivitis sicca), (Dry Eye), a common complication associated with cherry eye. KCS requires lifelong treatment, usually with topical cyclosporine, corticosteroids, and ocular lubricants.
CLINICAL SIGNS: Appearance of around, smooth, red mass near the medial canthus of a young dog is highly suggestive of a prolapsed gland of the third eyelid. Inflammation of the gland with swelling and redness may be present, but often the gland looks relatively normal, with a smooth, pink conjunctival surface. If the gland remains prolapsed for an extended period (months to years), the exposed conjunctiva overlying the gland often becomes pigmented, but there is no evidence of ocular pain. The gland usually remains prolapsed but occasionally repositions itself naturally or with gentle digital massaging. Even after repositioning, prolapse tends to recur.
DIAGNOSIS: Schirmer tear tests should be done on both eyes to assess reflex tear production has decreased or if the patient has developed KCS. Fluorescein staining should also be done to evaluate the effect of decreased tear production on the corneal surface.
HISTORY: The proper way to manage cherry eye was controversial for many years until it was determined that the gland is responsible for a significant amount of tear production in dogs. For years, practitioners either removed the gland or allowed the gland to remain prolapsed, but these approaches resulted in a high rate of KCS. Surgical replacement of the gland is now the overriding management strategy.
MANAGEMENT: Very young puppies (birth to about 3 months) presenting with unilateral cherry eye for a short duration that have no complications can be medically treated with eye medications for awhile (2-4 wks), because the gland in the other eye is likely to prolapse in the near future. If or when the other gland prolapses, surgical repair can be done as soon as the surgeon feels comfortable anesthetizing the small patient and handling the patient's tissue. Watchful waiting can also be used to manage older puppies and adults that have unilateral prolapse for a short duration (less than a month), but if prolapse occurred more than a month previously, surgery is recommended. Bilateral prolapses are always surgically repaired at the same time. Note: The longer the gland is exposed (months to years) the less likely surgical procedure will work, but it is always best to attempt the surgery before partial or total removal. Always remember to be using lubricant in the cherry eye to keep the tissue viable and healthy. At all times until surgery can be done.
SURGERY: Three basic surgical techniques have been described, but many variations have been reported. The basic methods include orbital rim anchoring; scleral anchoring; and, most recently, the pocket method. The method chosen is largely a matter of personal preference, but in a series of surgical corrections of 125 cases of cherry eye, the pocket method was the most successful (94%, compared with 41 % with the scleral anchoring method, independent of surgeon.
In brief, the pocket method involves parallel incisions made anterior and posterior to the gland. The gland is then easily tucked into the pocket and conjunctival edges are sutured closed using a continuous suture pattern with the knots tied on the palpebral surface to avoid abrading the cornea. Absorbable suture is used by most surgeons. Some surgeons recommend a second row of sutures, suggesting a higher success rate. Some surgeons suggest leaving the two ends of the incision open to allow tears to escape more easily from the created pocket. Postoperative triple antibiotic ointment is applied two to three times daily for 2-3 weeks.
PATIENT MONITORING: An Elizabethan collar should remain in place if patient is rubbing at eyes. The patient should be examined 2 weeks after surgery to ensure proper healing without corneal ulceration.
PROGNOSIS: Morgan and colleagues reported that only 10% of eyes in which the gland was repositioned developed KCS, whereas a total of 85% of patients with glands that were partially or totally excised or that remained prolapsed developed KCS.
NOTE: Cases of cherry eye in Bulldogs and Mastiffs seem to be most difficult to manage, and the surgeon may elect to pretreat the inflamed gland with topical corticosteroids to improve success.
Kenneth L. Abrams, DVM, Diplomate ACVO, Veterinary Ophthalmology Services, Inc, Warwick, Rhode Island
Blue Ravine Animal Hospital