When a tear duct is blocked, tears can't drain in the usual way, causing the eye to be watery and irritated. The condition is caused by a partial or complete blockage in the tear drainage system.
A blocked tear duct is common in newborns. The condition usually gets better without any treatment during the first year of life. In adults, a blocked tear duct may be due to an injury, an infection or, rarely, a tumor.
A blocked tear duct can almost always be treated. Treatment depends on the cause of the blockage and the age of the affected person.

Tear glands, also called lacrimal glands, located above each eyeball continuously supply tear fluid that's wiped across the surface of the eye with each blink of the eyelids. Excess fluid drains through the tear ducts into the nose.
Symptoms of a blocked tear duct include:
See a healthcare professional if your eye tears constantly for several days or if your eye is infected often or all the time. A blocked tear duct may be caused by a tumor pressing on the tear drainage system. Finding the tumor early can give you more treatment options.
Blocked tear ducts can happen at any age, from birth to adulthood. Causes include:
The lacrimal glands produce most of the eyes' tears. These glands are located inside the upper lids above each eye. Typically, tears flow from the lacrimal glands over the surface of the eye. Tears drain into openings called puncta on the inside corners of the upper and lower eyelids.
The puncta lead to small canals called canaliculi. Canaliculi move tears to a sac on the side of the nose called the lacrimal sac. From there, tears travel down the nasolacrimal duct and drain into the nose. Once in the nose, tears are absorbed again.
A blockage can happen at any point in the tear drainage system, from the puncta to the nose. When that happens, tears don't drain properly, causing watery eyes and increasing the risk of eye infections and irritation.
Certain factors increase the risk of developing a blocked tear duct:
Because 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 frequent eye infections and inflammation.
Any part of the tear drainage system, including the clear membrane over the eye surface, known as the conjunctiva, can become infected or inflamed because of a blocked tear duct.
To reduce the risk of developing a blocked tear duct later in life, get prompt treatment of eye inflammation or infections. Follow these tips to avoid eye infections in the first place: