Signs and symptoms of a blocked tear duct include:

• Excessive tearing
• Redness of the white part of the eye
• Recurrent eye infection or inflammation (pink eye)
• Painful swelling near the inside corner of the eye
• Crusting of the eyelids
• Mucus or pus discharge from the lids and surface of the eye
• Blurred vision

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. Often a thin tissue membrane remains over the opening that empties into the nose (nasolacrimal duct).
• Age-related changes. As you age, the tiny openings that drain tears (puncta) may get narrower, causing blockage.
• Infection or inflammation. Chronic infection or inflammation of your eyes, tear drainage system or nose can cause your tear ducts to become blocked.
• Injury or trauma. An injury to your face can cause bone damage or scarring near the drainage system, disrupting the normal flow of tears through the ducts. Even small particles of dirt or loose skin cells lodged in the duct can cause blockage.
• Tumor. A tumor in the nose or anywhere along the tear drainage system can cause blockage.
• Eyedrops. Rarely, long-term use of certain medications, such as eyedrops used to 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.

How the tear drainage system works

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 the puncta, located in the inside 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.

Certain factors increase your risk of developing a blocked tear duct:

• Age and sex. Older women are at highest risk of developing blocked tear ducts due to age-related changes.
• Chronic eye inflammation. If your eyes are continually irritated, red and inflamed (conjunctivitis), you're at higher risk of developing a blocked tear duct.
• Previous surgery. Previous eye, eyelid, nasal or sinus surgery may have caused some scarring of the duct system, possibly resulting in a blocked tear duct later.
• Glaucoma. Anti-glaucoma medications are often used topically on the eye. If you've used these or other topical eye medications, you're at higher risk of developing a blocked tear duct.
• Previous cancer treatment. If you've had radiation or chemotherapy to treat cancer, particularly if the radiation was focused on your face or head, you're at higher risk of developing a blocked tear duct.

Because your tears aren't draining the way they should, the tears that remain in the drainage system become stagnant. This promotes growth of bacteria, viruses and fungi, which can lead to recurrent eye infections and inflammation.

Any part of the tear drainage system, including the clear membrane over your eye surface (conjunctiva), can become infected or inflamed because of a blocked tear duct.