Blocked Tear Duct (Nasolacrimal Duct Obstruction): Causes and Treatment

Clinically reviewed by Dr. Ponlawat Pitsuwan, Physician, Doctor Bangkok. Last reviewed: August 2026

If your eye keeps watering and nothing fixes it, you are probably not imagining things. I see this regularly in clinic, usually from patients who have been blinking away tears for weeks, assuming it is Bangkok’s heat, pollution, or the air conditioning. Sometimes it is. But when watering comes with sticky discharge, swelling near the inner corner of your eye, or a nagging sense of pressure, that is a different problem.

Nasolacrimal duct obstruction means the drainage tube that removes tears from your eye is blocked. Tears have nowhere to go, so they spill over. The fix depends on what is causing the blockage and how complete it is. We can assess this properly, explain your options clearly, and refer you to the right specialist if surgery is needed.

How Tears Drain and Why a Blockage Makes Your Eye Overflow

Tears drain every time you blink. They are pushed toward two tiny openings at the inner corner of each eyelid, called the puncta. From there, tears travel through small tubes into a small sac beside your nose, then down the nasolacrimal duct into your nasal cavity. That is why your nose runs when you cry.

When any part of that path is blocked, tears back up and spill over your lower eyelid. Mucus and bacteria can also build up in the sac, leading to discharge and sometimes infection.

Congenital vs Acquired Nasolacrimal Duct Obstruction

There are two main types, and the cause matters for treatment.

In newborns and infants, the blockage is usually present from birth. A thin membrane at the lower end of the duct has not opened fully. This is common, and many cases resolve on their own within the first year with gentle massage and watchful waiting.

In adults, the obstruction develops over time. The most common form is gradual narrowing of the duct with no obvious single cause, seen most often in middle-aged and older women. Other causes include scarring from injury, chronic sinus problems, previous nasal or facial surgery, and, less commonly, growths near the drainage pathway.

Causes and Risk Factors in Adults

Most adults with a blocked tear duct do not have one clear cause. Age-related narrowing is the most common driver. The duct wall thickens slowly over time, often without any triggering event.

Chronic sinusitis is a genuine risk factor. Ongoing nasal inflammation can affect the surrounding tissue and eventually narrow the duct. If you have had repeated sinus infections, mention this when you come in.

Two risk factors that almost never get raised are long-term use of certain glaucoma eye drops and some chemotherapy drugs. Patients using drops like timolol or latanoprost daily for years can develop progressive duct narrowing. If you are on either of these and your eye has been watering, tell your doctor both facts together. It changes what we look for.

Nasolacrimal Duct Obstruction vs Other Causes of Watery Eyes

Watery eyes are common in Bangkok. Heat, pollution, heavy air conditioning, screen fatigue, and allergies all cause tearing. Most of the time, the cause is not a blocked duct.

If both eyes water with itching or burning, think allergies or dry eye. Dry eye can seem counterintuitive, but a dried-out eye surface triggers a flood of reflex tears that has nowhere productive to go. Blepharitis, which is inflammation along the eyelid margin, also causes watering in both eyes along with crusting and irritation.

A blocked duct is more likely when watering is mainly in one eye, focused at the inner corner, and comes with sticky or mucoid discharge but no itching. Pressing gently beside the nose near that inner corner may produce a small amount of mucus at the puncta. If you are seeing any of that, come in for a proper look.

Diagnosing a Blocked Tear Duct

The first step is your history and a look at the eye. I want to know which eye, how long it has been happening, whether there is discharge, and any history of sinus problems, surgeries, or current eye drops.

From there, we do a fluorescein dye disappearance test. A small drop of yellow dye goes into each eye. In a normal drainage system, the dye clears from the eye surface within a few minutes. If it stays on one side, drainage on that side is slow or blocked. It takes about five minutes and involves no discomfort.

If we need more detail, we can gently flush a small amount of saline through the puncta. If it flows freely into the nose and throat, drainage is intact. If it comes back out or meets resistance, the duct is blocked. Imaging may be arranged before surgery to map the anatomy clearly.

Treatment Options for Nasolacrimal Duct Obstruction

Treatment follows a logical ladder. Where you start depends on your age, the severity of the blockage, and whether infection is present.

In infants, the first step is massage. A gentle downward stroke beside the nose several times a day can help open the membrane. Most cases resolve this way. If massage fails after several months, a brief procedure under light anaesthesia is usually the next step.

In adults, conservative measures do not fix the structural problem. The definitive treatment is dacryocystorhinostomy, or DCR. This creates a new drainage pathway between the tear sac and the nasal cavity, bypassing the blocked duct entirely.

DCR can be done two ways. External DCR uses a small incision beside the nose. Endoscopic DCR goes entirely through the nose with no external scar. Both approaches have strong success rates when performed by an experienced oculoplastic surgeon. Most patients go home the same day and return to light activity within a few days.

Symptoms That Need Prompt Attention

Persistent watering alone is worth investigating but is not urgent. Some symptoms are.

Dacryocystitis is an infection of the tear sac. It causes pain, redness, and swelling at the inner corner of the eye, sometimes with fever. The skin can become tense and warm. This needs prompt assessment and antibiotics. Left untreated, it can spread to surrounding tissue.

There is also a practical concern before eye surgery. If you are planning cataract surgery or any procedure on the eye surface, an unresolved blocked duct must be addressed first. Operating on an eye with a chronically blocked, bacteria-colonised drainage system raises infection risk significantly. I flag this regularly for patients over 50 coming in before elective eye procedures.

Getting Assessed at Doctor Bangkok

This is not a condition most clinics think to check in a general appointment. At Doctor Bangkok, we see it more often than you might expect, particularly in expats who have put up with a watery eye for months assuming it is just the environment.

Consultations are in English, and same-day appointments are usually available. We take a full history, examine the eye, and can perform the dye disappearance test during your visit. If a structural blockage is confirmed and surgical management is needed, we coordinate referral to an experienced oculoplastic surgeon in Bangkok with clear communication throughout.

You do not need a referral letter to come in. If your eye has been watering for more than a few weeks, especially with any discharge, get it looked at properly. That is the right next step.

Can a blocked tear duct clear up on its own in adults?

In infants, yes, most cases resolve within the first year. In adults, the blockage is structural and almost never resolves without treatment. Conservative measures can reduce discomfort, but the underlying problem stays. If your eye has been watering consistently for more than a few weeks, get it assessed rather than waiting it out.

How do I know if my watery eye is a blocked duct rather than dry eye or allergies?

The pattern matters. A blocked duct tends to cause watering in one eye, focused at the inner corner, often with sticky discharge but no itching. Dry eye and allergy watering usually affect both eyes and come with burning, itching, or general redness. If you are not sure, the dye disappearance test at Doctor Bangkok can help distinguish them quickly.

Is DCR surgery available in Bangkok, and what does recovery look like?

Yes, DCR is performed in Bangkok by oculoplastic surgeons. There are two approaches: external DCR with a small incision near the nose, and endoscopic DCR through the nose with no visible scar. Both are done under anaesthesia and most patients go home the same day. Doctor Bangkok can assess your situation and arrange referral to a specialist if surgery is the right step.

Can a blocked tear duct lead to a serious infection?

It can. The tear sac can become infected, a condition called dacryocystitis, causing pain, swelling, redness, and sometimes fever at the inner corner of your eye. This needs prompt treatment with antibiotics and sometimes drainage. A chronically blocked duct also raises infection risk before eye surgery, which is why clearance beforehand matters.

What should I expect at my first appointment for this?

We take a full history, examine the eye, and can perform a fluorescein dye disappearance test on the same visit. If the picture points to a structural blockage, we talk through next steps, which may include further assessment or specialist referral. Appointments at Doctor Bangkok are in English and same-day bookings are usually available.

Are glaucoma eye drops really linked to blocked tear ducts?

Yes, with long-term daily use. Certain topical glaucoma medications used for years can gradually narrow the nasolacrimal duct. If you use these drops and have developed persistent watering, mention both at your consultation. It changes the clinical picture and affects what we look for.