The recurrence rate after surgery is high. If non-surgical methods are used to treat pterygium when surgery is not yet needed to make it subside or control its development and avoid surgery, recurrence can also be avoided. In this paper, we review the non-surgical treatment of pterygium. [Keywords] Pterygium; non-surgical; surgery; recurrence; treatment Pterygium is an eye disease with a high prevalence and surgical recurrence rate. Its etiology is complex, and from an epidemiological point of view, the cause is closely related to the living and working environment, etc. Most researchers believe that the occurrence of pterygium is related to sand, smoke, wind and dust, sunlight and other infrared radiation. The pathogenesis is not fully understood and is currently thought to be due to a combination of environmental and many physical factors [1]. Treatment of the disease is based on surgical excision, and although there are various methods to reduce the recurrence rate, postoperative recurrence cannot be completely avoided, and recurrence can be avoided if it can be treated earlier by non-surgical methods to make it subside or control its development and avoid surgery. The non-surgical treatment of pterygium has been studied by domestic and foreign scholars, and the literature is reviewed as follows: 1 Drug therapy 1.1 Hormonal therapy The development of pterygium is immunologically related [2], and is associated with type I and type III allergic reactions. a study by Pinkerton [3] found that type I and type II allergic reactions may be involved in the development of pterygium. Hormones have a significant inhibitory effect on several parts of the immune process, causing consolidation, rupture and lysis of sensitive lymphocytes [4]. Liu Xixiu [5] tried 5 mg/ml dexamethasone injections into the head and neck tissue, 0.3-0.5 ml each time depending on the size of the pterygium, usually one injection at an interval of about 7 days, 4-6 times as a course of treatment. In 40 cases (45 eyes), 66.7% were effective; 33.3% were effective; the total effective rate was 100%. This method is simple, less painful, safe and reliable. Nie Xiaomin [6] explored the treatment of pterygium with local injection of dexamethasone plus antibacterial drugs. 2.5 mg of dexamethasone plus 20,000 units of gentamicin and 0.3 ml of 2% lidocaine were injected into the bulbar conjunctiva of the head and neck of pterygium once every 4 days, 5 times for a course of treatment. This method is simple and economical. The use of hormones in the treatment of pterygium is very common, but currently they are more often used as an adjunctive medicine, and it is not common to use them alone. 1.2 Non-steroidal steroidal drug treatment Many patients suffer from eye redness, tearing, pain, foreign body sensation and other discomforts. Local drops of non-steroidal steroidal anti-inflammatory drugs such as anti-inflammatory pain, diclofenac sodium and pralophine can significantly relieve these symptoms. NSAIDs indirectly affect certain growth factors through q-inflammation and inhibition of prostaglandin release. For some patients who do not want surgery, topical drops of NSAIDs can play q-inflammation, relieve eye discomfort, and inhibit the growth of pterygium. Clinical reports on the use of topical drops of these drugs for pterygium are scarce, and prospective studies are lacking. MMC inhibits endothelial cell proliferation and causes endothelial cell contraction, fragmentation, and platelet adhesion, leading to thrombosis and vascular occlusion. MMC can inhibit endothelial cell proliferation and cause endothelial cell contraction, fragmentation, platelet adhesion, leading to thrombosis, vascular occlusion, and atrophy of the proliferating conjunctiva by blocking the blood supply for therapeutic purposes. It is also believed that the use of MMC can weaken the process of inhibiting the inflammatory response, thus causing vascular occlusive arteritis, promoting vascular degeneration, and preventing fibrous tissue proliferation to prevent the recurrence of pterygium. MMC is an anti-tumor antibiotic and its anti-inflammatory effect may weaken the proliferation process of pterygium. In recent years, MMC has been increasingly used in the treatment of pterygium. It can be administered topically by drop or injection, and mitomycin C for eye drops is often formulated to a concentration of 0.02%. Low concentrations can cause mild to moderate conjunctival congestion, delayed conjunctival wound healing, and conjunctival epithelial defects. High concentrations can cause moderate superficial punctate keratitis and mild anterior chamber reactions [8]. The concentrations of mitomycin C in eyes with severe complications were above 0.04% and the average duration of administration was more than 2 weeks [9]. [9]. When using mitomycin as an adjunctive therapy, the lowest possible concentration and the shortest duration can reduce the occurrence of serious complications such as secondary glaucoma, corneal perforation and scleral softening. Concurrent use of corticosteroids can reduce congestion, drug irritation, and blepharoconjunctivitis. For subconjunctival injections, mitomycin C is formulated in concentrations of 0.004% to 0.04% [10, 11]. 0.004% mitomycin C is administered at 0.2 ml per injection and can be injected subconjunctivally once a day for 3-7 times [10]. 0.04% mitomycin C Use 0.2 to 0.3 ml for one injection only and repeat treatment can be done after 2 months [11]. Yang Jing [11] used 0.4 mg/ml of mitomycin C 0.2 to 0.3 ml as a single injection in the body of the pterygium to treat pterygium in 40 eyes with good efficacy and no serious complications. However, similar to topical drops of this drug, the best efficacy and safety under which use (e.g., frequency, concentration and amount of administration and whether to combine the drugs to increase efficacy) also need to be further explored. Applications of 5-fluorouracil: MMC is toxic to both proliferating and quiescent cells. Unlike MMC, 5-fluorouracil has a weaker effect than mitomycin C, but only has a toxic effect on proliferating cells, which is far less toxic than mitomycin C. It is a safer fibrous tissue inhibitor without serious complications such as scleral lysis [12] and is inexpensive. Prabhasawat P [13] showed that in 39 eyes of patients who had pterygium excision for less than 6 months and were about to recur, they received 5 mg of 5-FU injection weekly for 2 weeks. The results showed that 5-FU was significantly more effective in inhibiting the recurrence of pterygium compared with glucocorticoid drops alone, and the recurrence-free period was significantly longer than that of the control group. Wu [14] gave patients subconjunctival injections of 5-fluorouracil at 5 mg each time starting the day after pterygium excision, once daily for the first 3 days and once every other day thereafter for 5-7 times, and no significant ocular side effects were found. However, some scholars [15] treated with 5-fluorouracil sponges placed intraoperatively at a concentration of 10 mg/ml for 5 min and found that the recurrence rate of pterygium was even higher than that of the distilled water control group. The reason for this analysis is that 5-fluorouracil acts as an inflammatory stimulant and instead promotes the growth of fibrous tissue. Cao Zhiping [16] reported that intravitreal injection of 5-Fu into pterygium, 0.2 ml each time, once a day, for a total of 5 times a course, was used to treat a patient with grinding pain in the right eye after the second injection for 1 d, accompanied by photophobia, lacrimation and blurred vision. The effect of 5-fluorouracil in the treatment of pterygium and its safety need to be further studied. The main component of pterygium is a large number of proliferating fibroblasts, and pinyamycin is a q-tumor drug that effectively inhibits fibroblast proliferation. In a study by Qian Zajiao [17], 8 mg of pinyamycin was added to 0.8 ml of saline and 5 mg of dexamethasone, and 0.1-0.2 ml was injected into the cervical part of the pterygium, once/30 days, 2-3 times as a course of treatment. The treatment effect of pinyamycin was significantly better than that of surgery. In recent years, the molecular pathology of pterygium by Chen et al. and Denrass et al. has demonstrated that pterygium fibroblasts fully possess various biological characteristics of tumor cells. In particular, recurrent pterygium exhibits the absence of multiple oncogenes, and Spandidos et al. suggested that pterygium should be attributed to the category of benign conjunctival tumors [18]. Pingyangmycin is a broad-spectrum antitumor agent that selectively inhibits skin cancer, and histologically speaking, conjunctiva and skin are derived from the same ectodermal genesis, so pingyangmycin is also selective for lesions in conjunctival tissue [19]. Since pinyamycin has the effect of inhibiting angiogenesis, DNA, RNA and protein synthesis and nuclear mitosis, local injection of a small amount of the drug in pterygium can strengthen this effect, directly interfering with the metabolism of pterygium, causing vascular occlusion of pterygium and lack of blood supply, which can inhibit the growth of fibroblasts and disrupt the metabolism of pterygium to make it atrophy, while pinyamycin also has anti-infective effect on pterygium tissue, which can both inhibit its vascular proliferation and promote In addition, pinyamycin has an anti-infective effect on pterygium tissue, which can both inhibit its vascular proliferation and promote the degeneration of pterygium tissue with existing vascular climbing. Accordingly, Li Yuqin [19] injected pinyamycin directly into the body of pterygium near the neck for pterygium invading <3 mm, causing all the pterygium tissue to bulge, 1 mg (0.1 mL) per injection. 24 eyes (92%) of 26 eyes gradually lost the pterygium, 2 eyes (8%) stopped development; 7 eyes (27%) showed a little bit of corneal staining in the second day, which disappeared after 3 d. No complications such as high intraocular pressure and cataract were found. No complications such as hypertension or cataract were found. Pingyangmycin injection treatment was performed at the early stage of pterygium, with good therapeutic effect, without the need of multiple injections or even surgical treatment, less painful for patients, less side effects, simple and economical. Wang Yun et al [20] treated pterygium with pinyamycin injections at a concentration of 0.1 mg/0.1 mL. Each injection was 0.1-0.3 mL. 1 injection was given in 7-10 days, and 3-5 injections were used as a course of treatment. 227 eyes were cured 193 eyes (85.02%), 32 eyes (14.1%) were effective, and 2 eyes (0.88%) were ineffective after the treatment. A good efficacy was achieved. Each patient was followed up for a minimum of six months and a maximum of more than 2 years without any abnormalities. In addition, anti-metabolic drugs such as scramycin have been shown to be effective in the treatment of pterygium [21,22,23]. qMetabolic drug therapy injected to treat pterygium can cause the body of the pterygium to turn white, atrophy and stop proceeding, but it cannot change the morphology of the pterygium, so it is more valuable to use at the early stage of the disease. 1.4 Peptidase Wan Jinlan et al [24] based on the abnormal expression of tumor necrosis factor-α in pterygium tissue; TNF-α activity was also detected in the culture supernatant of pterygium tissue, which can promote the proliferation of pterygium fibroblasts in vitro, and the ability of peptidase to inhibit TNF-α production in keratinized cells induced by UV light. The effect of peptidase on TNF-α production by pterygium fibroblasts induced by hydrogen peroxide was investigated, and it was found that peptidase could significantly inhibit TNF-α secretion by pterygium fibroblasts induced by hydrogen peroxide at concentrations of 1500 U/ml and 3000 U/ml; and this concentration had no proliferation-promoting effect on pterygium fibroblasts. The study concluded that TNF-α plays an important role in the formation and recurrence of pterygium, and peptidase can significantly inhibit the secretion of TNF-α by pterygium fibroblasts induced by hydrogen peroxide, so peptidase can be used for the prevention and treatment of pterygium. The therapeutic effect of laser on pterygium needs further long-term and extensive clinical studies. There is no single non-surgical treatment method that has been universally adopted. Various non-surgical treatments are still being explored, such as: timing, method, and frequency of treatment. As research progresses, the etiology and pathogenesis of pterygium is gradually being understood, which will help explore newer treatment methods and make future treatments more complete. With the accumulation of clinical treatment cases, it is expected that the ideal method with definite efficacy, few side effects, and ease of use will be generally accepted.