The operation steps of lacrimal flushing: 1, the patient takes a supine or sitting position with the head fixed. 2.First, press the lacrimal sac area with fingers to exclude the fluid in the lacrimal sac, and pay attention to whether there is secretion overflow at the tear dots. 3, 1 to 2 drops of epi-anesthetic in the conjunctival sac, or a cotton swab soaked with epi-anesthetic and then clamped between the upper and lower lacrimal puncta for 3 to 5 minutes. 4, Use the operator’s index and thumb of one hand to separate the upper and lower lids of the patient or use a cotton swab to fully expose the lower tear dots and make the patient look upward, if the tear dots are narrow, they need to be enlarged with a tear duct dilator. 5.Take the flushing syringe in the other hand and insert the flushing needle vertically into the lower tear dots about 1.5 to 2 mm, and then advance about 5 to 6 mm horizontally toward the inner canthus to touch the bone wall. 6. Back off the needle by 1 to 2 mm and slowly inject the rinsing fluid. Ask the patient if there is any fluid entering the pharynx. 7, Then flush the upper tear duct according to the law. Tear duct flushing often reveals the site of lacrimal obstruction. A blunt round needle is used to inject saline from the lacrimal punctum, and the presence or absence of obstruction and the site of obstruction is determined according to the flow of the flushing fluid. There are usually the following situations: 1.No resistance to irrigation, the liquid enters the nasal cavity or pharynx smoothly, indicating that the lacrimal duct is open; 2.The irrigation liquid returns completely from the original way of injection, which is an obstruction of the lacrimal duct; 3.The irrigation liquid is injected from the lower lacrimal dots, and returns from the upper lacrimal dots, which is an obstruction of the common lacrimal duct or nasolacrimal duct; 4.The irrigation has resistance, partly returns from the lacrimal dots and partly flows into the nasal cavity, which is a narrowing of the nasolacrimal duct; 5.The irrigation liquid returns from the upper lacrimal 5, the flushing fluid from the upper lacrimal dots return, while there is mucopurulent discharge, for the nasolacrimal duct obstruction combined with chronic dacryocystitis.