Any high technology wants to be applied in medical treatment, and laser is no exception. Now laser not only has many medical applications, but also improves certain medical methods to a better and more refined level.
1. Femto second laser treatment for myopia
Surgery in the eyeball requires very precision. Now, lasers can be used to correct vision, weld the retina, etc. These laser surgeries are so perfect that they have fundamentally changed traditional eye surgeries.
The basic structure of the eyeball and the cause of refraction.
First, let’s briefly understand the basic structure of the eyeball.
Everyone knows that the cause of myopia is that light is focused in front of the retina, and the cause of hyperopia is that light is focused behind the retina.
The causes of myopia include the following three points: genetics, environment, and eye habits.
For myopia, why does light focus in front of the retina? There are two main reasons. One is that long-term ciliary muscle contraction increases the curvature of the lens; the other is caused by corneal thickening, which increases the curvature of the lens. As myopia lasts for a long time, the physiological axis behind and behind the eyes will become longer, and the light will focus in front of the retina.
Surgery to treat myopia is nothing more than two aspects: one is to replace the lens with a different curvature, and the other is to change the diopter of the cornea.
For the elderly, the purpose of treating myopia or hyperopia can be achieved by replacing the lens with a different curvature.
For young people, it is not practical to replace the lens, so change the radius of curvature of the cornea. Experiments and research have shown that the curvature radius of the cornea should be changed within 3 mm of the center of the eyeball to achieve the purpose of changing the diopter of the eyeball. Traditional eye surgery cannot change the radius of curvature of the cornea, but laser surgery can because the focus of laser surgery can be adjusted within the molecular size range.
In 1971, laser was first used in eye surgery. After decades of development, laser surgical correction has almost gone through six development stages and surgical improvements. Currently, there are basically three major types of corneal laser surgery to correct myopia, "excimer laser" "In situ keratomileusis", "half-femtosecond laser in situ keratomileusis" and "full femtosecond laser corneal stromal lens removal" can all change the corneal diopter to achieve the purpose of correcting myopia.
At present, it is recognized that the best methods are: "half-femtosecond laser myopia treatment" and "full femtosecond laser myopia treatment".
2. Excimer laser in situ keratomileusis
During the operation, a micro-knife is used to cut a thin pedicled corneal flap on the cornea, the flap is opened, laser "grinding" is performed under the flap, and then the upper corneal flap is "set" back in place. This can be used for low, medium and high myopia. In this surgery, after incision under the flap, the cut upper corneal flap needs to be closed. Problems such as corneal flap wrinkles and displacement often occur at the edge of the corneal flap.
3. Semi-femtosecond laser myopia treatment
A "femtosecond laser device" is used to cut a thin pedicled corneal flap on the cornea, open the flap, perform laser "grinding" under the flap, and then "set" the upper corneal flap back to its original position. Therefore, compared with "excimer laser in situ keratomileusis", the only difference is that "femtosecond laser equipment" is used.
4. Full femtosecond laser myopia treatment
Use the "femtosecond laser equipment" to cut a circular layer at a certain depth of the cornea. At this time, the surface of the cornea is complete. Go deeper, cut another circular layer, and then make a small opening on the corneal flap. Pull out the separated corneal tissue (which is a layer of tissue). Therefore, "Full Femtosecond" only uses femtosecond laser equipment to cut without "grinding".
5. Full femtosecond and half femtosecond security
Both procedures are accurate down to molecular weights. Since the full-femtosecond surgery is a minimally invasive incision of only 2-4mm, it is theoretically better than the half-femtosecond surgery.
The applicable range of full femtosecond is from myopia of 200 degrees to myopia of 1000 degrees.
The applicable range of half femtosecond is from farsightedness of 600 degrees to myopia of 1200 degrees.
In terms of scope of application, half femtosecond has a wider range than full femtosecond, which also reflects that half femtosecond has lower requirements for patients than full femtosecond.
The advantages of femtosecond laser treatment for myopia are:
High accuracy. The degree of correction between the actual effect and the target effect is approximately within ±50 degrees.
High security. The surgery is performed only on the front stroma of the cornea, with no damage to the corneal epithelium and endothelial cells. There is no scarring or tissue left on the cornea after the surgery, and the chance of corneal opacity is small.
High stability. The postoperative corneal stroma healed quickly, the postoperative power changes were slight, and the stability was good.
The operation time is short. Laser measurement of correction takes about 30 seconds per eye; only local anesthesia is required before surgery; the corneal flap incision procedure takes about 10 seconds per eye; vision improves immediately after surgery and you can return home.
High comfort. There were no symptoms of pain and photophobia such as corneal epithelial cell defects, keratitis, etc. after the operation.
Contact Person: Mrs. Nica Chow