There is a tear gland wrapped around the cartilage of the third eyelid that is a major source of tears for the eye. In a dog with cherry eye, the fibrous attachments to the undersurface of the third eyelid are weak. This allows the gland to prolapse, or bulge out from beneath the eyelid, exposing a cherrylike growth that is really a normal-size tear gland. This growth can irritate the surface of the eye and produce recurrent conjunctivitis.
Cherry eye is a congenital defect that occurs most commonly in Cocker Spaniels, Beagles, Boston Terriers, and Bulldogs.
Treatment: Removing the third eyelid or the tear gland seriously interferes with tear production and may result in a dry eye syndrome in breeds so disposed (see Tearing Mechanism in dogs). If the gland is removed, your dog may require artificial tears daily for life. Instead, surgery can be performed that repositions the third eyelid and the tear gland. This corrects the problem while maintaining tear production.