Blocked tear ducts happen when the small drainage channel that carries tears from your eye into your nose becomes partially or fully obstructed. The causes range from a membrane that hasn’t opened at birth to infections, injuries, and even certain medications. Understanding why the blockage occurred matters because the cause shapes how it’s treated and whether it will resolve on its own.
Tears don’t just evaporate off your eyes. After washing across the surface, they drain through tiny openings in the inner corners of your eyelids, travel through narrow channels, and empty into the nasolacrimal duct, a passage that runs through the nasal bone and deposits fluid into the back of your nose. A blockage anywhere along this path traps tears, causing them to pool, overflow down your cheek, or create a breeding ground for infection.
Blocked Tear Ducts in Newborns
About 20% of infants worldwide are born with some degree of tear duct obstruction, making this the most common cause overall. The blockage is almost always caused by a thin membrane at the very bottom of the duct, at a spot called the valve of Hasner, that simply hasn’t opened by the time the baby is born. Think of it like a sealed envelope: the duct is fully formed, but the exit into the nose is still covered.
Roughly 5% of infants develop noticeable symptoms like watery eyes or crusty discharge. In most cases, the membrane opens on its own during the first year of life without any treatment. Parents are typically advised to gently massage the area between the inner corner of the eye and the side of the nose to help encourage the membrane to open. Occasionally, a cystic swelling forms near the duct when fluid backs up behind the sealed membrane. These cysts are usually managed conservatively but sometimes need a minor procedure to open the passage.
Infections and Inflammatory Conditions
Infections are both a cause and a consequence of blocked tear ducts. Repeated sinus infections or eye infections can inflame and scar the narrow drainage channels, gradually narrowing them until tears can no longer pass through. Once the duct is blocked, stagnant fluid trapped inside can itself become infected, a condition called dacryocystitis. You’ll notice a painful, red, swollen bump near the inner corner of the eye, sometimes with thick yellow-green discharge and fever. Acute dacryocystitis is a medical emergency that requires prompt antibiotic treatment.
Chronic, whole-body inflammatory conditions can also damage the tear drainage system from the inside. Sarcoidosis, lupus, and granulomatosis with polyangiitis all involve immune-driven inflammation that can thicken and obstruct the delicate lining of the duct over time. If you have one of these conditions and notice persistent tearing on one side, the two problems may be connected.
Facial Injuries and Surgical Damage
The tear drainage system sits in a physically vulnerable spot. It runs through thin bone between the eye socket and the nasal cavity, directly in the path of common facial injuries. Midface trauma is the leading non-surgical cause, particularly fractures of the naso-orbitoethmoid complex (the bony area between and behind the bridge of your nose). A broken cheekbone or a blow to the middle of the face can crush, displace, or scar the duct. Even after fracture repair, malpositioned bone fragments can compress the channel.
Surgery in the area carries risk too. Endoscopic sinus surgery is a well-known culprit because the tear duct sits right next to the structures surgeons work on inside the nose. Rhinoplasty (“nose jobs”), orbital surgery, and other craniofacial procedures can also inadvertently damage the drainage pathway. This type of blockage tends to develop gradually as scar tissue forms in the weeks or months following the procedure.
Tumors and Growths
Tumors in or near the tear drainage system are rare, but they deserve mention because they’re frequently misdiagnosed as simple chronic blockage. Most people with a lacrimal sac tumor show up with the same symptom as any other blocked duct: persistent tearing on one side, sometimes with a palpable lump near the inner corner of the eye.
The majority of these tumors (60 to 94%) arise from the lining tissue of the sac itself. Among benign growths, papillomas are the most common, making up about 36% of these lining-tissue tumors. They’re thought to develop from long-standing inflammation. Some papillomas grow aggressively and can transform into squamous cell carcinoma, so even “benign” growths in this area need careful monitoring. Malignant tumors can also arise on their own without a pre-existing growth. Because these tumors mimic ordinary blockage so closely, a blockage that doesn’t respond to standard treatment or that involves a firm mass warrants further investigation.
Chemotherapy Medications
Certain cancer drugs are secreted into tears at concentrations high enough to damage the tear drainage channels from the inside. The best-documented offender is docetaxel, a chemotherapy agent derived from yew tree bark and widely used for breast, lung, and prostate cancers. Up to 50% of patients receiving weekly docetaxel therapy develop excessive tearing, and the damage often does not reverse after treatment ends. The drug causes scarring and narrowing of the tiny openings and channels that tears pass through before reaching the main duct.
Its chemical relative, paclitaxel, has been linked to similar problems. If you’re undergoing chemotherapy and notice one or both eyes constantly watering, mention it to your oncologist early. Catching the narrowing before it becomes a complete blockage gives you more treatment options.
Age-Related Narrowing
In adults with no history of injury, surgery, or inflammatory disease, the most common cause is simply gradual narrowing of the duct over time. The drainage passage naturally becomes less efficient with age as the lining tissue thickens and the channel diameter shrinks. Women are affected more often than men, possibly because of hormonal influences on the duct lining. This type of blockage tends to develop slowly, starting as intermittent tearing that eventually becomes constant.
How a Blockage Is Diagnosed
The standard office test is straightforward. Your doctor places a drop of fluorescein dye (the same bright yellow-orange dye used in routine eye exams) into both eyes and watches what happens over five minutes. In a healthy system, the dye drains away and only a trace remains. If the dye pools heavily in one eye, or if there’s a clear difference between the two sides, the drainage system on the affected side is obstructed. In the most obvious cases, dye-stained tears overflow and run down the cheek.
For more detailed mapping, your doctor may gently flush saline through the drainage openings to feel where resistance occurs, or order imaging to look for the exact location and cause of the blockage. The location matters because a blockage high in the system (near the eyelid openings) calls for a different approach than one at the bottom of the duct near the nose.