1.Why does pus flow from the inner corner of the eye? Under normal circumstances, people secrete 0.6ml of tear fluid from the tear glands of the eyes 16 hours a day during the day. Tear fluid is a weakly alkaline transparent liquid, which contains a small amount of protein and inorganic salts, in addition to lysozyme, immunoglobulin A (IgA), complement system, beta lysin and lactoferrin. Therefore, in addition to its clearing effect, tear fluid also has a cleansing and sterilizing effect. After the tears are discharged to the conjunctival sac, they are distributed on the surface of the eye by blinking and converge on the tear lake toward the inner corner of the eye, entering the tear dots in the inner corner of the eye, and the siphoning effect of the tear ducts, entering the tear ducts and flowing to the nasal cavity, and the eyes will not have tears out. Under normal circumstances, the tear drainage unimpeded, once the nasolacrimal duct or the lower part of the tear sac is blocked, tears long term accumulation in the tear sac, its temperature and humidity is very suitable for bacterial growth and reproduction, it will cause chronic inflammation of the tear sac wall, the more tears accumulate, the tear sac becomes larger and thicker, the tear sac in the tear sac becomes pus, therefore, when squeezing the tear sac area (large corner of the eye) by hand, mucus or viscous pus can be seen overflowing from the tear dots. It is called chronic dacryocystitis. The purulent secretions are discharged into the conjunctival sac, causing skin flushing and erosion in the lacrimal sac area to become eczematous blepharitis and conjunctivitis. 2. What are the risks of chronic dacryocystitis to the eyes? Chronic dacryocystitis can also affect vision, and in more serious cases, lead to corneal ulcer perforation and blindness. In addition, those who need surgery for glaucoma and cataract, because of chronic lacrimal sacitis, bacteria can invade through the surgical incision after surgery, resulting in endophthalmitis, so before doing glaucoma and cataract surgery, to cure the chronic lacrimal sacitis. Chronic dacryocystitis, although the skin of the dacryocyst area is not red, swollen, or painful, is blocked at the lower end of the nasolacrimal duct, and there is stagnant tear fluid in the dacryocyst, which is conducive to the growth of pathogenic bacteria such as pneumococcus, streptococcus, staphylococcus, and sometimes anaerobic bacteria. Antibiotics are difficult to work, the effect is poor, patients often lose confidence after several times of drug treatment, think there is no good way, give up treatment. The bacteria in the tear sac is like a “bacteria bank” that is a “landmine” that poses a threat to the health of the eye. If the conjunctiva and cornea are traumatized, the bacteria in the tear sac will attack the wound and cause keratitis or corneal ulcers, which can be difficult to heal and even lead to blindness. In addition, chronic dacryocystitis due to the long-term presence of a large number of bacteria in the tear sac, this chronic inflammation will not heal on its own, and at any time there may be an acute attack, redness, swelling, heat, pain around the tear sac, the formation of abscesses can break through the epidermis, drain the pus on its own, can form the sieve sinus “tear sac fistula”, this fistula is difficult to completely cure. This shows that the potential risk of chronic lacrimal sacs to the eyes should not be underestimated and should not be taken lightly. 3, chronic dacryocystitis how to treat? (1) Local medication: Patients suffering from chronic lacrimal sacitis that cannot be treated surgically for various reasons can first squeeze the pus out of their lacrimal sac and then apply local antibiotic drops to their eyes, and after a period of treatment, the purulent discharge can disappear. However, the problem of obstruction and retention is not solved, and the pus may flow again after some time. (2) Tear duct flushing: In order to clear the pus as soon as possible, the tear sac can be flushed with saline once a week, and after flushing, 0.3 to 0.5 ml of antibiotics can be injected. Antibiotic eye drops. (3) Surgical treatment: feasible lacrimal duct exploratory surgery, if exploratory surgery 2 to 3 times no effect consider other surgical treatment. The lacrimal duct prosthetic tube implantation is the surgical way to solve the lacrimal duct obstruction which has emerged in recent years, and its advantages are no wound and little trauma. Lacrimal sac nasal anastomosis is the most ideal treatment for chronic dacryocystitis, removing both the purulent lesions and resolving tear overflow. For the elderly, lacrimal sac removal can be considered. 4, chronic dacryocystitis how to prevent Chronic dacryocystitis is associated with nasolacrimal duct obstruction, which can be caused by many reasons. In addition to trachoma, blepharitis, lacrimal ductitis and other eye diseases, anatomical factors are also closely related, such as the width and length of the nasolacrimal duct, nasal septum deviation, inferior turbinate hypertrophy, chronic rhinitis and other nasal inflammation spread to the mucosa in the nasolacrimal duct, congenital nasolacrimal duct malformation, nasal tumors, surgery, fractures, etc. can lead to nasolacrimal duct obstruction and cause chronic dacryocystitis. Therefore, the prevention of chronic lacrimal sac should pay attention to the following points: (1) pay attention not to rub the eyes with dirty hands, keep the eyes clean. (2) timely treatment of eye diseases, such as trachoma, blepharitis, lacrimal ductitis and other eye inflammation, to prevent bacterial invasion of the tear sac. (3) Patients with deviated nasal septum, enlarged inferior turbinate, and chronic rhinitis should be treated as early as possible.