Refractive regression after myopic LASIK is defined as a non-undercorrected deviation from the corrective target-0, 50 D and above-residual myopia, a gradual, partial or total loss of refractive correction that affects the predictability, long-term stability and effectiveness of the procedure. Its incidence has been reported inconsistently, ranging from 5,5% to 27,7%. The main risk factors for refractive regression after LASIK for myopia include: 1. Corneal damage repair The corneal damage repair process is an important factor affecting the stability and predictability after LASIK. a certain thickness of stromal corneal flap is created during LASIK, preserving the integrity of the corneal epithelium, epithelial basement membrane and anterior elastic layer in the central region, stromal cell apoptosis and myofibrillar Corneal damage repair reactions such as stromal cell apoptosis and myofibroblast generation are milder than PRK, so from the perspective of corneal damage repair, LASIK has a lower incidence of postoperative haze and myopic refractive regression than PRK; 2, anterior corneal convexity After myopic LASIK, the central corneal stromal plate layer is weakened by excimer laser ablation and its biomechanical strength. Under the action of IOP, progressive corneal anterior convexity is the primary cause of myopic refractive regression after LASIK. Therefore, for myopic refractive regression due to corneal proptosis after LASIK, if further stromal laser ablation is performed on the residual corneal stromal bed, it will cause further damage to the structural integrity of the cornea, thus further reducing the tensile strength of the cornea, exacerbating corneal proptosis and myopic refractive regression, or even corneal dilatation and medically induced cone corneas; 3. Early after LASIK, the cornea is in a period of damage repair and stromal reconstruction, and if its tensile strength is not sufficient to counteract the effect of intraocular pressure, myopic refractive regression will occur, at which time the intraocular pressure can still be in the normal range. When the corneal damage repair stabilizes, the corneal tensile strength returns to normal and is sufficient to counteract IOP strength, and corneal proptosis stops or can even be reversed. Therefore, the early application of IOP-lowering medication after LASIK can alleviate myopic refractive regression; 4, preoperative corneal thickness and postoperative residual corneal stromal bed thickness Preoperative corneal thickness is thin, due to the decline in corneal tensile strength after LASIK, more likely to occur myopic refractive regression. If the residual corneal stromal bed is too thin, its strength is not enough to resist the action of intraocular pressure, there will be progressive corneal proptosis and progressive corneal thinning, dilatation, and even corneal bulge; 5, pre-correction refraction and excimer laser ablation depth It is generally believed that high myopia is prone to myopic refraction after LASIK, which is related to the correction of high myopia requires ablation of more corneal stroma, the deeper the ablation stroma during surgery The deeper the stroma is ablated, the less the postoperative residual stromal thickness, the weaker the postoperative corneal tensile strength; 6, corneal flap thickness and diameter The thicker the corneal flap, the thinner the postoperative corneal residual stromal bed thickness. In addition to the requirement to make a thin corneal flap, the diameter of the flap should not be too large and should match the ablation range of the excimer laser; 7, postoperative dry eye and inflammation After damage to the nerve fibers in the anterior corneal stroma, neuropeptides such as calcitonin will be upregulated and released into the tear fluid, which may be involved in the corneal damage repair process. The risk of refractive regression after LASIK is closely related to dry eye, and those with dry eye symptoms have an increased risk of refractive regression. In conclusion, myopic refractive regression after LASIK may be caused by a single risk factor or may be the result of a combination of risk factors. Therefore, it is important to conduct adequate preoperative screening and assessment of risk factors, personalize the intraoperative design of the corneal flap, strictly control the depth of stromal ablation, and effectively treat dry eye and related ocular surface diseases and control IOP after surgery.