Nearsighted, farsighted, and astigmatic eyes have difficulty seeing due to abnormal curvature of the corneal surface (too convex, too flat, or irregular) or abnormal length of the eye (too long or too short), which results in external light not being accurately focused in the retina under the eye. The excimer laser is actually a super ultraviolet beam invisible to the human eye, produced by mixing fluorine-argon gas after excitation, with a wavelength of 193 nanometers, which can be precisely focused and controlled, and its cutting accuracy is very accurate. Each pulse can cut a precise 0.25 micron thickness of corneal tissue. The excimer laser breaks the chemical bonds of tissue molecules by photochemical action, which enables tissue cutting by “irradiating” the corneal tissue to precisely remove part of the corneal stroma and match the curvature of the cornea to the length of the eye. As a result of these features, the excimer laser has a neat cutting edge and can achieve very precise treatment results. In addition, the excimer laser is a cold laser that produces no thermal damage, making it very safe to treat. In layman’s terms, the laser beam “irradiates” the human cornea to “sculpt” a pair of suitable glasses so that external light can be accurately focused on the retina for the purpose of restoring vision. With the development of excimer devices, laser surgery has taken a new leap forward, such as personalized excimer laser surgery under wavefront aberration guidance. Wavefront aberrometry technology clearly shows the patient’s unique “eye fingerprint” and allows the surgeon to grasp the aberration of the entire visual path, not just the refraction of light from the pupil surface. This aberrometry information is combined with routine testing information and fed into the excimer laser device, allowing for better results in personalized cutting. The key: A thorough preoperative examination is essential Numerous ophthalmologists agree that a detailed and accurate preoperative examination is the key to successful surgery. More than 10 examinations, including visual acuity examinations, refractive examinations, anterior segment and fundus examinations, etc., are required before excimer treatment surgery is to be performed. According to the ophthalmologist, the more data about the myopic patient’s eyes, the better the surgery will be. However, each hospital has different examination items, and some patients may need more items to be examined. Before undergoing excimer laser surgery, the following examinations should be performed: first, vision examination, including bare eye vision and best corrected vision with lenses; second, refractive examination, including computerized optometry, dilated optometry and re-testing in three steps, in which the correctness of the optometry directly affects the surgical effect; third, anterior segment and fundus examination, focusing on corneal transparency, whether there is scarring in the cornea, whether the crystal is cloudy, and whether there is vitreous turbidity. Fourth, eye pressure examination to exclude the possibility of high eye pressure and glaucoma; fifth, corneal curvature examination to exclude the possibility of cone corneas and flat corneas; sixth, corneal thickness measurement for safe surgical volume design; seventh, corneal topography examination, the main purpose is to understand the regularity and symmetry of the entire corneal surface, to exclude cone corneas and other The eighth, wavefront aberration examination, to check whether there are higher-order aberrations that seriously affect visual quality, in addition to lower-order aberrations such as myopia, hyperopia and astigmatism, and to collect higher-order aberration data as the basis for diagnosis and surgery.