When you have a blocked tear duct, your tears can't drain normally, leaving you with a watery, irritated eye. The condition is caused by a partial or complete obstruction 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 is almost always correctable. Treatment depends on the cause of the blockage and the age of the affected person.