Hello parents, based on the questions asked online, we would like to introduce the following knowledge about the lacrimal duct obstruction disease that parents ask more frequently, and hope that you will have a better understanding of the disease after reading it. Congenital nasolacrimal duct obstruction (CNDO) is the most common cause of lacrimal overflow in infants and children. Approximately 6-20% have clinical symptoms. Although some children with CNDO improve and recover on their own within one year of birth, many still have persistent or recurrent symptoms that place a heavy burden on themselves and their parents. Regardless of the viewpoint, it is crucial to develop an appropriate treatment plan for children with CNDO. Children with CNDO present with persistent tearing, recurrent purulent discharge, and reflux of secretions by squeezing the lacrimal sac area. About 14-33.8% of children have bilateral tear duct involvement. Lacrimal sac massage is the most common method of conservative treatment and is performed by increasing hydrostatic pressure to rupture the membranous obstruction of the nasolacrimal duct. A randomized controlled study showed that proper massage was more effective than simple massage and no massage in children with CNDO. High-pressure irrigation has been shown to be effective in children with CNDO, and the younger the child, the higher the success rate. Tear duct probing is usually used as the first-line treatment for CNDO. The literature reports that the success rate of lacrimal ductal exploration in children younger than 12 months of age can reach 78-100%, and the overall success rate of lacrimal ductal exploration in our ophthalmology department is over 95%. Factors that influence the cure rate of lacrimal ductal exploration include age (some studies have shown that success rates decrease with age), severity of symptoms, bilateral obstruction, luminal narrowing, atelectasis, and non-membranous obstruction. After failed exploration, a variety of treatment options are available, including continued observation, re-exploration, silicone tube insertion, balloon dilation, lacrimal sac nasal anastomosis, and inferior turbinate dissection. Silicone tube insertion has been shown to be effective in cases of failed access, local obstruction or increased local resistance, with a success rate of 79.6% to 91.3% in children of different ages. The disadvantage is that the silicone tube is left in place for a long time (3-6 months), which causes inconvenience to the child’s life, and the silicone tube may displace or cause tearing of the lacrimal duct, corneal damage, lacrimal tract infection, and nasal inflammation. Balloon dilation is a more effective method for children with extensive lacrimal stenosis, with a success rate of 74-94%, but it is expensive and takes a long time to leave in place. Nasal lacrimal sac anastomosis (DCR) is rarely used, but it can still be used in cases of bony obstruction and tear sac bulge where all the above methods have failed. Based on our clinical experience, lacrimal ductal exploration is simple, effective and has a high cure rate, and should be the preferred treatment method in order to cure the disease in the simplest and most economical way and minimize the pain of the child.