In response to the special requirements of summer high school students’ examinations and military examinations, and many parents and students are particularly concerned about femtosecond laser treatment for myopia, the following explanations are given for the questions raised by you, hoping that it will help you to choose femtosecond laser. 1. What is femtosecond surgery? Femtosecond laser is a laser that operates in pulses of very short duration, only a few femtoseconds, a femtosecond is 10-15 seconds, that is, one trillionth of a second, it is thousands of times shorter than the shortest pulses obtained by using electronic methods, and is the shortest pulse available to mankind under experimental conditions. This is the first characteristic of the femtosecond laser. The second feature of the femtosecond laser is that it has a very high instantaneous power, which can reach one million billion watts, a hundred times more than the total power generated worldwide. The third feature of the femtosecond laser is that it can focus to a region of space smaller than the diameter of a hair, making the electromagnetic field several times stronger than the force of an atomic nucleus on its surrounding electrons. In the medical field, the femtosecond laser can be used as an ultra-precise surgical scalpel and has been successfully applied in the field of ophthalmology, where it is used to create corneal lamellar flaps in excimer laser treatment of myopia, as well as other corneal surgeries. 2. Is femtosecond laser surgery safe? Compared to mechanical lamellar knife, the biggest advantage or specialty of femtosecond laser for LASIK myopia is that it produces a very precise flap thickness, with an accuracy (average fluctuation: 10-15um) three times higher than the accuracy of lamellar knife (average fluctuation: 30-45um), and the actual probability of flap complications is tens of thousands of times lower. In addition, the negative pressure of the suction ring used to create the flap with the femtosecond laser (approximately 35 mmHg) is significantly lower than that used to create the flap with a mechanical corneal laminotome (approximately 65 mmHg). Therefore, the use of femtosecond laser to create the corneal flap can greatly improve the surgical safety of excimer laser treatment for myopia, especially for patients with thin corneas, large corneal curvature variation, and high myopia is a great blessing. 3.What are the most serious complications of femtosecond laser surgery? Femtosecond LASIK surgery is an all-laser LASIK procedure that uses a femtosecond laser to make a corneal flap. Because it does not require a mechanical blade to make the flap, Femtosecond LASIK eliminates almost all serious complications caused by flap making. From the results of the nearly 300,000 femtosecond LASIK surgeries that have been performed, no serious complications related to the procedure have been identified. 4. Who is performing femtosecond laser surgery at your hospital? The main surgeon of our hospital, Prof. Wang Hui, is a nationally renowned refractive surgeon with extensive surgical experience and has successfully performed tens of thousands of myopia surgeries. 5.Difference between femtosecond laser surgery and conventional excimer laser surgery Femtosecond laser surgery is different from conventional mechanical lamellar excimer laser surgery, mainly in terms of flap production: Femtosecond laser surgery uses a laser to produce a corneal flap without a blade, while conventional excimer laser surgery uses a laser to produce a corneal flap without a blade. Conventional excimer laser surgery uses a mechanical corneal lamellar knife to create the corneal flap, and the excimer laser cutting after the flap is completed is the same. The biggest advantage or specialty of the femtosecond laser for LASIK is that it produces a very precise flap thickness, which is three times more accurate (fluctuating from 10 to 15 um) than the laminar knife (fluctuating from 30 to 45 um), and the actual probability of flap complications is tens of thousands of times lower. Therefore, the use of femtosecond laser to create the corneal flap can greatly improve the surgical safety of excimer laser treatment for myopia, especially for myopic patients with thin corneas and large corneal curvature variants 6. Are the post-operative results better than those of conventional excimer laser surgery? Femtosecond laser has been used for excimer laser in situ keratomileusis (LASIK) flap making for more than 3 years since it was approved by the FDA in 2002. To date, nearly 300,000 patients have undergone femtosecond LASIK. Because of the high precision and safety of the femtosecond laser flap making, the occurrence of serious complications due to corneal fabrication is avoided, and the surface of the flap made with the femtosecond laser is smoother, so that better results than conventional LASIK surgery can be obtained after the surgery. 7. Are there any failed cases of femtosecond laser surgery? Femtosecond laser LASIK surgery only uses the laser when making the flap, but the excimer laser is used for the corneal cutting part after the flap is made. Therefore, the success or failure of the whole surgery is not only related to the flap making, but also the excimer laser cutting. From the existing hundreds of thousands of patients who have undergone femtosecond laser LASIK surgery, although the vast majority of patients achieved very satisfactory results, but there are still a few patients with unsatisfactory vision after surgery. 8.What are the advantages of femtosecond laser surgery over conventional excimer laser surgery? Femtosecond laser surgery is different from conventional mechanical lamellar excimer laser surgery in that the flap is made with a laser and no blade is needed, whereas conventional excimer laser surgery uses a mechanical lamellar knife to make the flap and the excimer laser cutting is the same after the flap is made. The biggest advantage or specialty of the femtosecond laser for LASIK myopia is that it produces a very precise flap thickness that is three times more accurate (fluctuating from 10 to 15 um) than the laminar knife (fluctuating from 30 to 45 um), and the actual probability of flap complications is tens of thousands of times lower. In addition, the negative pressure of the suction ring used to create the flap with the femtosecond laser (approximately 35 mmHg) is significantly lower than that used to create the flap with a mechanical corneal laminotome (approximately 65 mmHg). Therefore, the use of femtosecond laser to create the corneal flap can greatly improve the surgical safety of excimer laser treatment of myopia, especially for myopic surgery patients with thin corneas and large corneal curvature variation. 9. Will glare and double vision occur after femtosecond laser surgery? Femtosecond laser surgery uses a laser to create a corneal flap without a blade, which can produce a flap with a very precise thickness and a smoother surface. Therefore, the occurrence of glare and double vision after surgery can be reduced. However, the occurrence of glare and double vision after surgery is not only related to the corneal flap, but also related to the smoothness of the excimer laser corneal cutting surface, the size of the higher-order wavefront aberration after surgery, and the size of the pupil. Femtosecond laser surgery also has the possibility of glare and double vision, but since the corneal flap is smoother, less glare and other phenomena will occur after surgery. 10. Is there any pain during the femtosecond laser surgery? Femtosecond laser surgery is different from conventional mechanical lamellar excimer laser surgery in that the flap is made with a laser and no blade is needed, whereas conventional excimer laser surgery uses a mechanical lamellar knife to make the flap and the excimer laser cutting is the same after the flap is made. The surgery is performed under surface anesthesia, which means that two drops of eye drops are all that is needed for the surgery. There is a transient dark haze and a feeling of pressure and distention during the flap creation procedure, and there is no significant pain.