Nasolacrimal Duct Obstruction

The naso-lacrimal duct (tear duct) is a passageway connecting the eye to the nose and mouth. Tears produced in the eye normally drain through this duct. There are two openings (puncta) to the duct on each eye; one is located on the upper lid, and the other is on the lower lid. If the naso-lacrimal duct is obstructed, excess tears spill over the lids onto the face. As a result, the primary symptom associated with an obstructed naso-lacrimal duct is excess tearing. (*Please note that excessive tearing is a common symptom of a number of other ocular issues in addition to nasolacrimal duct obstruction).

There are several possible causes of a blocked tear duct. Debris may accumulate in the narrow passageway. There may be a congenital defect of the duct; some patients are born without a complete puncta, and in others the duct may be too narrow or too kinked to allow fluid to pass. In older patients, we sometimes suspect a tumor may be pressing on and closing the passageway.

During the examination of your pet, we will test the patency of the eyelid punctae and nasolacrimal duct using a fluorescein green dye. If the dye fails to passively flow out the nose and the duct is obstructed due to debris, we may be able to manually “flush” out the duct to remove the obstruction. As this involves working right next to the globe (eye), this procedure requires extreme caution and should only be performed by a trained professional. In cooperative patients, this procedure can be attempted in the exam room after the eye has been numbed with topical anesthetic drops. If this is unsuccessful, a surgical approach may be discussed.