The best time to perform lacrimal duct probing is usually chosen when the baby is between 3 and 6 months old. This is because the residual membrane at the end of the nasolacrimal duct of the baby’s tear duct is still relatively thin during this period and the inflammation of the tear duct is not very obvious, so it is more effective to perform the exploration. When the early stage of tear sac obstruction is found, you can choose conservative treatment methods, such as massage of the tear sac area, tear duct flushing, and ordering antibiotic drops. With the above conservative treatment, some babies can return to normal. If the above conservative treatment is not effective, the baby should have a tear duct exploration at 3-6 months. If the baby’s tear duct has no obvious inflammation and adhesions, the probing effect is better. If your baby has more severe tearing symptoms, or if there is more discharge, you can also advance the time to about two months. If the baby is too old for lacrimal duct probing, the effect of the probing may be affected by the thick residual membrane or the inflammation of the lacrimal duct. Therefore, parents should take their babies to the hospital in time for early detection and treatment of lacrimal duct obstruction.