Babies don’t cry, but their eyes are always teary, even teary, as if they have an endless supply of tears. Why is this? The most common reason for this condition is that the baby has congenital nasolacrimal duct obstruction. Congenital nasolacrimal duct obstruction is due to congenital abnormalities in the development of the nasolacrimal duct. Usually the nasolacrimal duct is closed at the opening of the nasal cavity by an undegraded membrane-like structure, so that the normal channels of tear drainage are blocked, so that the baby is always tearful all day and night, and over time, the skin at the inner canthus often has tear marks. If the result is not good or if the child is a little older, consider performing a lacrimal duct exploratory surgery, the best time to operate is 2 months to 4 months after birth, the surgery is very traumatic, does not require hospitalization and has good clinical results. Congenital nasolacrimal duct obstruction is a common and frequent disease in pediatric ophthalmology clinics, and most children suffer from lacrimal sacculitis at the same time. If treatment is delayed, there can be serious harm. Therefore, it is recommended to young parents: if you find that your child has the above mentioned condition, you should go to the hospital in time to get early diagnosis and timely treatment.