Causes of chronic inflammation of the lacrimal sac The lacrimal duct is composed of the upper and lower lacrimal dots, upper and lower lacrimal ducts, common lacrimal duct, nasolacrimal duct and lacrimal sac, and finally opens in the lower nasal duct. When the nasolacrimal duct is obstructed, tears are not discharged smoothly, and a large amount of tears accumulate in the tear sac, which becomes a place for bacteria to hide and reproduce, and when the temperature and humidity of the tear sac and tear fluid are suitable for bacteria to grow and reproduce, a large amount of bacteria grow and reproduce in the tear sac, which eventually leads to the occurrence of chronic dacryocystitis. The main pathogenic bacteria causing chronic dacryocystitis is S. pneumoniae. Tearing and pus flow are common manifestations of chronic dacryocystitis. When squeezing the lacrimal sac area, mucopurulent secretions can be seen overflowing from the tear dots into the conjunctival sac. The dangers of chronic lacrimal sacs Because chronic lacrimal sacs do not cause discomfort or affect vision, they are easily overlooked by patients, but in fact they are very dangerous. When the eye is accidentally injured, even if it is a minor corneal abrasion, the bacteria hidden in the pus will take advantage of the situation and cause keratitis or corneal ulcers, which can leave scarring on the cornea after healing in mild cases and corneal perforation or even blindness in severe cases, causing irreparable damage. Also, chronic lacrimal sacitis poses a potential threat to eye surgeries such as cataract removal surgery, glaucoma surgery, myopia surgery, etc. If the pre-existing chronic lacrimal sacitis is not detected before the eye surgery, it may cause serious infections after the surgery, such as endophthalmitis and corneal infection, which may cause destruction of the eye and lead to serious consequences such as eye blindness or even eye removal. Therefore, tear duct flushing should be routinely performed before eye surgery to detect chronic dacryocystitis in time, and if combined with chronic dacryocystitis, the chronic dacryocystitis must be cured before surgery. In addition, chronic dacryocystitis may have an acute attack and form a dacryocystic fistula, which is difficult to cure completely because of the long-term flow of pus. If chronic dacryocystitis is not treated in a timely manner, it will continue to pose many of the above-mentioned threats to the eye, so ophthalmologists often compare chronic dacryocystitis to a “ticking time bomb” for the eye. Chronic dacryocystitis treatment Because chronic dacryocystitis is caused by nasolacrimal duct obstruction leading to tear sac infection, it cannot be cured by medication, which requires surgical methods to restore lacrimal duct patency and adequate drainage of the lacrimal duct in order to solve the problem. The other category is to perform tear duct rerouting to restore the patency of the tear duct, such as: tear sac nasal anastomosis, transendoscopic tear sac nasal anastomosis, etc. Chronic dacryocystitis due to long-term chronic inflammation, nasolacrimal duct obstruction is very serious, the use of lacrimal duct exploration, lacrimal duct laser lacrimal duct angioplasty can not effectively unblock the blocked tear duct, in the clinical treatment of chronic dacryocystitis is rarely used. At present, the commonly used methods are nasolacrimal duct stent implantation and nasolacrimal duct stent implantation, lacrimal sac nasal anastomosis: a 2 cm long incision is made in the skin of the lacrimal sac area in the inner canthus, and a hole of about 1.5 cm in diameter is cut in the nasal bone to reanastomose the lacrimal sac wall and the nasal mucosa together, so that the tears no longer go through the nasolacrimal duct, but enter the nasal cavity directly from the newly opened hole. This is like the diversion of a river, relieving the tear duct of its chronic pus accumulation and restoring the function of tear drainage. This method is not easily accepted by many patients due to the trauma, the complexity of its presence and most of all the scarring it leaves on the face, which affects the appearance, but it is the most effective method for the treatment of chronic lacrimal sacculitis and is the most commonly used method in clinical practice. Nasolacrimal duct stenting: A permanent tear drainage channel is placed between the lacrimal sac and the inferior nasal canal. The mushroom head in the lacrimal sac not only acts as a fixation, but also creates a siphoning effect on the tears in the conjunctival conjunctival sac due to the enlarged space and allows the tears in the conjunctival sac to collect in the lacrimal sac and reach the lower nasal tract through the drainage tube in the nasolacrimal duct, thus eliminating the patient’s tear overflow symptoms. The nasolacrimal duct stent implantation is a minimally invasive treatment method with the following advantages: 1, simple, safe and time-saving operation; 2, less bleeding and less pain, which can be tolerated by patients; 3, no change of the original anatomical position, and the stent can be implanted again after the obstruction of the stent or other treatment methods; 4, no skin cut, and no scar on the face after the operation; 5, a wide range of surgical indications, and a high success rate of the operation. It can be an ideal choice for patients who have high cosmetic requirements and do not want to leave scars on the face.