Many children are born with an underdeveloped tear-duct system, a problem that can lead to tear-duct blockage, excess tearing, and infection.

Blocked tear ducts are a fairly common problem in infants; as many as one third may be born with this condition. Fortunately, more than 90% of all cases resolve by the time children are 1 year old with little or no treatment. The earlier that blocked tear ducts are discovered, the less likely it is that infection will result or surgery will be necessary.

What Are Tear Ducts?
Our eyes are continually exposed to dust, bacteria, viruses, and other objects that could cause damage. The eyelids and eyelashes play a key role in preventing these objects from entering our eyes and hurting them. But besides serving as barriers, the lids and lashes also help our eyes stay moist. Without moisture, our corneas, which serve as protective domes for the front of the eyes, would dry out and could become cloudy or injured.

Working with our lids and lashes, the protective system of glands and ducts called the lacrimal system keeps our eyes from drying out. Small glands at the edge of the eyelid produce an oily film that mixes with the liquid part of our tears and keeps them from evaporating. Lacrimal (or tear-producing) glands secrete the watery part of tears. These glands are located under the brow bone behind the upper eyelid, at the edge of the eye socket, and in the lids.

Eyelids move tears across the eyes. Tears keep the eyes lubricated and clean and contain antibodies that protect the eyes from infection. They drain out of the eyes through two ducts called punctum or lacrimal ducts, one on each of the upper and lower lids. From these ducts, tears enter small tubes called canaliculi, which are located at the inner corner of the eyelids. They pass from the eyes into the lacrimal sac, a small sac that's located next to the inner corner of the eyes (between the eyes and the nose).

From the lacrimal sacs, tears move down through the nasolacrimal duct and drain into the back of the nose. (That's why you usually get a runny nose when you cry - your eyes are producing excess tears, and your nose can't handle the additional flow.) When you blink, the motion forces the lacrimal sacs to compress, squeezing tears out of them, away from the eyes, and into the nasolacrimal duct.

The nasolacrimal duct and the lacrimal ducts are also known as tear ducts. However, it's the nasolacrimal duct that's involved in tear-duct blockage.

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Jump to another section of this article Tear-Duct Obstruction and Surgery What Causes a Blocked Tear Duct? and Signs of Blocked Tear Ducts When to Call Your Child's Doctor and Treating Blocked Tear Ducts What Happens Before and During Surgery? and Taking Care of Your Child After Surgery Reviewer name and date on last page