The so-called ultra-thin LASIK is relative to the previous conventional LASIK. As we all know, LASIK surgery is performed by forming a flap in the cornea and then forming a smooth “concave biomirror” in the middle of the cornea (i.e., the stroma) according to the refractive power, and then covering the flap with an alignment. . In the process of flap formation, conventional LASIK forms a 160um flap, while ultra-thin LASIK forms a flap of only 110um. With ultra-thin LASIK, a “concave biolens” is formed on the 390um stromal bed, which preserves the thickness of the cornea and reduces the chance of risk, making the surgery safer.