Lacrimal duct obstruction in infants and young children is a common condition in ophthalmology clinics, and after birth, the nasolacrimal ducts of newborns are obstructed. Most of the obstructions are located in the lower nasolacrimal duct, sometimes occluded by epithelial debris, or congenital membrane closure, leaving tears in the lacrimal sac. Bacterial multiplication also causes chronic lacrimal sac inflammation, which mainly manifests as lacrimation or excessive discharge. In infants and children, nasolacrimal duct obstruction is due to a defective ductalization process. In the fetus, there is a membrane at the lower opening of the nasolacrimal duct, which should perforate naturally within a week or cause tearing if not perforated in time. The cause of most nasolacrimal duct obstruction is often the failure of the valve to dehiscence or the formation of a flap fold. The flap usually perforates itself during the first week of tear secretion in newborns, and in unperforated cases, mucus cysts or chronic dacryocystitis are often formed due to storage of secretions. In rare cases, the nasolacrimal duct is obstructed due to nasal malformation and bony lumen narrowing of the nasolacrimal duct, which prevents the flow of tears into the lower nasal passage and leaves the ripples in the lacrimal sac, allowing microorganisms to accumulate and multiply in the blind channel, resulting in lacrimal sac inflammation. Most children with lacrimal sacs are misdiagnosed after repeated visits. Some children are misdiagnosed with lacrimal discharge due to impingement and are not treated in time, and develop lacrimal sacculitis. Conservative treatment is used for children within 1 month, because some nasolacrimal duct obstructions can rupture on their own in the first week after birth. The pressure of massage can cause the closed membrane to rupture and heal. For congenital nasolacrimal duct obstruction, the treatment method and treatment time are still controversial, some think that this kind of nasolacrimal duct obstruction can often disappear on its own in the first years of life, and infants can be treated conservatively first, we think it is more difficult to perform lacrimal duct exploration because of the thickening of the flap at too old age. However, special care should be taken when performing flushing in infants less than 1 month of age, as the flushing pressure should not be too high and care should be taken to prevent aspiration pneumonia due to uncoordinated swallowing movements in newborns. It is safer to perform lacrimal tract exploration or irrigation at around 4 months of age. Because of the fragility of the tissues of the child, it is important to be gentle and precise when probing to avoid tearing the lower tear duct or forming a false tract.