CausesBy Mayo Clinic staff
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|Tear glands and tear ducts|
The lacrimal glands produce most of your tears. These glands are located inside the upper lids above each eye. Normally, tears flow from the lacrimal glands over the surface of your eye. Tears drain into tiny holes (puncta) located in the corners of your upper and lower eyelids.
Your eyelids have small canals (canaliculi) that move tears to a sac where the lids are attached to the side of the nose (lacrimal sac). From there, tears travel down a duct (the nasolacrimal duct) draining into your nose. Once in the nose, tears are reabsorbed.
A blockage can occur at any point in the tear drainage system, from the puncta to your nose. When that happens, your tears don't drain properly, giving you watery eyes and increasing your risk of eye infections and inflammation.
Blocked tear ducts can happen at any age. They may even be present at birth (congenital). Causes include:
- Congenital blockage. Many infants are born with a blocked tear duct. The tear drainage system may not be fully developed or there may be a duct abnormality. A thin tissue membrane often remains over the opening that empties into the nose (nasolacrimal duct) in congenitally blocked tear ducts. This usually opens spontaneously during the first or second month of life.
- Age-related changes. As you age, the punctal openings may get narrower, causing partial blockage that slows the flow of tears into the nose, resulting in tearing. Total blockage of the punctal openings also may occur.
- Eye infections or inflammation. Chronic infections and inflammation of your eyes, tear drainage system or nose can cause your tear ducts to become blocked.
- Facial injuries or trauma. An injury to your face can cause bone damage near the drainage system, disrupting the normal flow of tears through the ducts.
- Tumors. Nasal, sinus or lacrimal sac tumors can occur along the tear drainage system, blocking it as they grow larger.
- Topical medications. Rarely, long-term use of certain topical medications, such as some of those that treat glaucoma, can cause a blocked tear duct.
- Cancer treatments. A blocked tear duct is a possible side effect of chemotherapy medication and radiation treatment for cancer.
- Riordan-Eva P, et al. Vaughan & Asbury's General Ophthalmology. 18th ed. New York, N.Y.: The McGraw-Hill Companies; 2011. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=720. Accessed Jan. 3, 2013.
- Dantas RRA. Lacrimal drainage system obstruction. Seminars in Ophthalmology. 2010; 25:98.
- Cohen NA, et al. Prevention and management of lacrimal duct injury. Otolaryngology Clinics of North America. 2010;43:781.
- Dacryostenosis. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/print/eye_disorders/eyelid_and_lacrimal_disorders/dacryostenosis.html. Accessed Jan. 6, 2013.
- Nasolacrimal duct obstruction. American Association for Pediatric Ophthalmology and Strabismus. http://www.aapos.org/terms/conditions/72. Accessed Jan. 4, 2013.
- Yanoff M, ed., et al. Ophthalmology. 3rd ed. Edinburgh, U.K.: Mosby Elsevier; 2009. http://www.mdconsult.com/das/book/body/212799885-2/0/1869/0.html. Accessed Jan. 3, 2013.
- Karim R, et al. A comparison of external and endoscopic endonasal dacryocystorhinostomy for acquired nasolacrimal duct obstruction. Clinical Ophthalmology. 2011;5:979.
- Robertson DM (expert opinion). Mayo Clinic, Rochester, Minn. Jan. 14, 2013.