Lacrimal flushing is a method of treating and diagnosing lacrimal disease and is a routine preoperative examination for all internal eye surgery. It is mainly done by a trained ophthalmic specialist nurse. Specific method: after 3-5 minutes of eye dabbing with surface anesthetic Benoxyl ophthalmic solution, use a 5ml irrigator and slowly inject saline after putting the irrigation needle into the tear dots, if it flows into the pharyngeal cavity, it means the tear duct is open, if not, it will overflow. Patient preparation and cooperation:The patient takes a sitting position with the head fixed, avoiding dodging and blinking, and keeping the direction of gaze. Caution:To prevent the needle from damaging the conjunctiva and cornea, the patient should not move around and squeeze the eyes with force.