Under normal circumstances, in addition to evaporating part of the human tears, the remaining part will flow through the tear duct into the nasal cavity and throat. The tear duct is like the “sewer” of the eye, if the “sewer” is blocked, tears will overflow out of the eye. People with obstructive lacrimal disease often have “inexplicable tears”. Chronic dacryocystitis is the most common form of lacrimal obstruction. The eyes are exposed to the air and are easily exposed to bacteria and impurities. Under normal circumstances, tears will flush out these impurities; if the tear duct is not accessible, tears containing bacteria will accumulate in the tear sac, and over time, infection will easily occur, leading to dacryocystitis. Patients with lacrimal sacitis often have symptoms of pus flowing from the corner of the eye, or purulent discharge overflowing when pressing on the corner of the eye. The pus contains a large number of bacteria, and it tends to adhere to the surface of the eye after overflowing. If there is a wound on the eye, the bacteria will “enter” and lead to conjunctivitis, keratitis, and even corneal ulceration and perforation. Ophthalmologists often compare chronic dacryocystitis to a ‘ticking time bomb’ next to the eye because of the many threats it poses to the eye.” Surgery is now recognized as a method that can effectively treat tear duct disease. However, traditional lacrimal sac nasal anastomosis has the disadvantages of being very invasive, bleeding significantly and leaving scarring on the face, which discourages many patients. In recent years, lacrimal specialists have made a major breakthrough by using the special physiological structure of the tear duct to complete lacrimal surgery with the help of nasal passages. Initially, the nasal endoscope was a tool for ENT surgeons, but after improvement, it has now become a “powerful tool” for ophthalmologists, making ophthalmic lacrimal surgery minimally invasive, or even ultra-minimally invasive. During surgery, the nasal endoscope system penetrates deep into the lacrimal tract, magnifying the surgical area and creating a micro-perforation in the non-functional area of the middle nasal tract, reducing the strain and damage to the mucosa caused by traditional surgical instruments, leaving the interior of the nasal cavity and normal tissues of the lacrimal tract unaffected, with little bleeding, high comfort, and a much shorter post-operative recovery period. Nasal endoscopic lacrimal sac perforation has the advantages of minimally invasive, rapid, high success rate, and no visual scarring. It can achieve good results for all kinds of difficult lacrimal tract diseases such as inflammation of the lacrimal sac that cannot be treated by laser and intubation, congenital and various factors causing lacrimal obstruction or narrowing, functional tear overflow, tear overflow and pus after external nasal lacrimal sac anastomosis. It is worth mentioning that the biggest difficulty of nasal endoscopic lacrimal sac osteotomy lies in the accurate grasp of the nasal anatomy. If the intraoperative positioning is not accurate (failure to detect ectopic lacrimal sacs, variation of surrounding tissues), the lacrimal sac may not be found, which will invariably increase the difficulty of the operation. Therefore, this type of surgery is also a challenge for the ophthalmologist. Nasal endoscopy: minimally invasive and painless cure for tear duct disease.