Tear overflow is mainly due to an obstruction in the tear drainage system (called the lacrimal duct), which prevents tears from draining smoothly. Tears are mainly secreted by the lacrimal gland in the upper part of the eye socket, which flows through the lower eyelid margin to the tear duct on the inside of the eye, and then flows through the lacrimal duct and the common lacrimal duct into the lacrimal sac, where the tears enter the nasal cavity through the nasolacrimal duct. This disease is often caused by tear dots abnormalities or tear duct abnormalities, tear dots ectropion, narrowing, occlusion or no tear dots, tears can not flow into the tear duct, developmental abnormalities (congenital atresia), trauma, foreign body, inflammation, tumor, scar contraction or nasal cavity disorders to narrow or obstruct the tear duct, can occur tear overflow. The location and condition of the obstruction can be clarified through slit lamp examination, tear duct irrigation, and tear duct probing, so that a personalized plan can be formulated. Tear duct obstruction can be treated by combined tear duct laser placement, and dacryocystitis can be treated by external method tear sac nasal anastomosis, nasal endoscopic nasal tear sac anastomosis, laser tear sac nasal anastomosis, and traumatic tear duct malformation can be treated by conjunctival tear sac nasal anastomosis.