The femtosecond laser (Da Vinci) is an infrared laser with a wavelength of 1045 nm, the shortest pulse available under experimental conditions. 1 femtosecond is equal to 1×10-15 seconds, i.e., 1/1000 trillionth of a second, and is able to focus to an ultra-fine spatial area much smaller than the diameter of a hair, emitting a very high instantaneous power that instantly turns gaseous, liquid or solid substances into plasma. In refractive corneal surgery, each plasma evaporates approximately 1 micron of corneal tissue, and the evaporated blisters and CO2 are absorbed and the corneal tissue is thus separated. No thermal effects or shock waves are generated during the entire procedure, resulting in no tissue damage. The Femtosecond laser has been internationally certified to replace the original “corneal lamellar knife” and produce a highly accurate corneal flap with the laser in a completely “knifeless” situation, truly achieving “full blade-free surgery “The Femtosecond laser has been used in refractive surgery for a long time. Femtosecond laser for refractive surgery is considered to be the third technological revolution in ophthalmology after micro-ophthalmic surgery and excimer laser for refractive errors.