Tears are a clear fluid made by the tear glands in the eye. The eyes continually produce tears. Tears keep the eyes lubricated and clean and contain antibodies that protect the eyes from infection.
The tears drain into tiny holes in the upper and lower lids, called puncta. The tears then go down small tubes (canaliculi) into the tear duct (lacrimal sac). Then they flow from the tear duct into the nose.
NLDO occurs when the flow of tears from the eye down through the tear duct to the nose is blocked. One or both eyes may be affected. Most commonly it’s caused by failure of a membrane at the end of the tear duct to open normally (at the time of birth). This causes the tears to build up in the duct and backflow into your child’s eyes.
Blocked tear ducts are usually present at birth (congenital) in about 6 out of 100 babies. Sometimes a blocked tear duct happens later in life (acquired). In most cases, a baby is born with a duct that is too narrow or has extra tissue blocking the duct.
The following are common signs and symptoms of a blocked tear duct:
Watery eyes
Eyelids may be red and swollen
Excessive tearing, even when your child is not crying (called epiphora)
During crying, nostril on blocked side remains dry
Child wakes up with a crust over the eyelid or in the eyelashes
Nasolacrimal duct obstruction - Blocked tear duct
