Chronic dacryocystitis is mostly secondary to narrowing or obstruction of the nasolacrimal ducts, with tears trapped in the tear sac, accompanied by bacterial infection, conjunctivitis and corner tearing is more obvious, serious cases can form corner pus or purulent cysts. Many patients think that tears are caused by certain stimuli, so they are often ignored and treatment is delayed. In fact, this is very dangerous. As the mucopurulent secretions return to the conjunctival sac for a long time, there are a large number of bacteria, and once the corneal epithelium is damaged, the bacteria in the secretions can cause infection, resulting in corneal ulcers. In case of eye perforation injury or internal eye surgery, it can also cause intraocular infection. For this reason, ophthalmologists refer to chronic lacrimal sac infection as a “ticking time bomb next to the eye”. Conventional lacrimal sac nasal anastomosis is performed through a skin incision on the face, and the bone at the base of the lacrimal sac is chiseled away so that the lacrimal sac goes straight through to the nasal cavity, after which a drainage tube is left in place to ensure the patency of the leak, which is removed by the nasal cavity after a few months. The surgery leaves facial scars and takes a long time to recover after surgery. In case of nasal diseases such as deviated septum, hypertrophic rhinitis or even sinusitis and nasal polyps, the surgery is often much more difficult for the ophthalmologist. Transnasal endoscopic lacrimal sac anastomosis is done completely in the nasal cavity, without facial incision, no scar on the face after surgery, no drainage tube can be placed, and the patient recovers quickly. However, it requires a high level of nasal endoscopic skills, so many rhinologists are able to perform this procedure. The advantages of nasal endoscopic lacrimal sac surgery have also been recognized by most ophthalmologists in recent years.