The laser I use is: Da. Finch Femtosecond Laser + Eagle Vision Blue Tone Cool Eye Excimer Laser, 1. Firstly, the head position should be set up, the left and right eyes should be at the same level; the plane of the corneal edge should be at the same plane as the microscope lens. 2, microscope first with 10 times magnification to the central cornea. 3, hold the laser handle, three drops of sodium vitreous acid on the corneal surface. And instruct the patient not to turn the eye after the drops of sodium glassate eye drops, so as not to remove the sodium glassate from the corneal surface, which affects the laser handle of the flattening cone lens is difficult to closely contact the good cornea. Do not exceed three drops of sodium glass, otherwise it will cause the corneal clear zone to easily exceed the yellow ring line, producing a gap between the pressed flat cone mirror of the femtosecond laser head and the corneal surface, finally leading to difficulties in lifting the flap. 4, to a good central cornea, let the negative pressure attraction ring fully contact the sclera, and gradually increase the pressure on the eye to make full contact between the cornea and the pressure leveling mirror of the femtosecond laser head, and the transparent area can exceed the yellow ring line. 5, start the negative pressure, after reaching the set negative pressure, the automatic prompt sound will be issued, at this time the pupil will expand; confirm that the set negative pressure is reached, start the femtosecond laser scanning. After completing the femtosecond laser scan, the negative pressure will be released automatically. Remove the femtosecond laser handle. 6. Use a microscope with 16x magnification to assess the quality of the corneal flap made by the femtosecond laser. If the quality is good then the excimer laser surgery can be continued. 7, Lift the flap technique: da. The corneal flap made by Da Vinci femtosecond laser has almost no gas bubbles and is very small, so you can lift the flap and excimer laser cutting without waiting. And it is easy to lift the flap. However, in patients with small lid fissures or eyes that move, there are some tips to lift the flap: try to get as close to the tip as possible as the starting point of the flap, because it is often difficult to find a breach at the beginning of the flap, and there will be some damage to the corneal flap edge while looking for a breach, and the flap may not close well after the surgery, so there should be upper lid pressure on the flap to avoid epithelial implantation between the layers. The flap edge is inserted along the margin to avoid blind rubbing resulting in epithelial loss, and can be inserted vertically at 90° and rapidly tilted into the interlamina. 8, After lifting the flap edge, the proximal tip is separated in a smooth manner, and the striker can be inserted along the proximal tip until it breaks through the flap edge on one side. Then partition the corneal flap, the flap edge separation of the pupil area should be separated at once, do not use the tip of the stripper to separate the pupil area corneal flap. 9, some corneal flaps will be difficult to separate the flap edge, then separate the interlayer first, and finally the flap edge, so that the stripper can be separated like a paper knife to separate the difficult flap edge. 10.Flip and fold the corneal flap, the tip should not be too wide, too wide when the operation of micro-tear is available to reduce the width of the flap tip. 11, after flipping the folded flap, dry cotton swabs (not yet used cotton swabs) can be used to absorb the water in the stromal bed, especially under the flap tip. 12, excimer laser cutting: instruct the patient to look squarely at the fixed green light above, pay attention to the corneal edge to maintain a horizontal plane, perpendicular to the laser beam, and try to keep the eye still until the laser scan is completed. In order to make the eye fixation indication light source more clear and convenient for the patient to gaze, the brightness of lighting etc. can be reduced appropriately. During the cutting process, the patient’s eye position should be closely monitored, and if there is any deviation, the foot switch should be released immediately to stop the laser emission, and then continue the excimer laser emission for cutting after adjustment. The excimer laser has a passive eye tracking system and an active tracking system. The passive eye tracking system will stop the laser automatically when the eye is shifted by 0.3-0.5mm; the active eye tracking system can track the laser within a certain range with the movement of the eye position. The corneal cutting surface should also be closely observed for excessive water. If there is too much water, excimer laser emission should be stopped and the excessive water should be dried up with a dry cotton swab to avoid the formation of a central island or undercorrection. The corneal flap diameter is small, or the laser cutting diameter is too large such as astigmatism or farsightedness treatment, care should be taken that the corneal flap and the tip are not cut by the laser to avoid damage to the cornea or irregular astigmatism after surgery. 13, corneal stromal bed and flap interlayer flushing: use BSS to push the flap to make reset, 14, corneal flap reset, rectify the flap edge: check the flap edge alignment, especially pay attention to lift the flap edge difficult to separate parts, such as feel less than ideal, then place the corneal contact lens, 12-36 hours to remove. This is a major difference from laminate flap making. Patients who are more afraid of pain may also be placed with a corneal contact lens.