Refractive surgery is a relatively young direction in the treatment of eye diseases. Based on the principles of refraction of light in such a way as to focus the image directly on the retina. Refraction is translated precisely as "refraction". Thus, refractive laser surgery uses the laws of physics from the subsection of optics. The procedure for correcting vision using this method can be applied to almost anyone from the age of 18 to the most advanced years.
Types of myopia and the physics of the correction process
The most common visual defects are nearsightedness and farsightedness. With myopia, a person cannot see objects far from him. With farsightedness, on the contrary, he clearly sees everything that is in the distance, while he is not able to see what is in front of his face, for example, he cannot read. This happens because the lens, being essentially a lens,focuses the image passing through it, not on the retina, but at a point in front of it - myopia or behind it - hyperopia.
To solve this problem is quite simple - you need to either move the lens to the fundus or move it away from it. But it is practically impossible to move the lens inside the eye, but it is possible, by changing the curvature of the horn-frill, to press it against the retina or move it away. Almost all vision corrective surgeries are based on this principle. They change the curvature of the anterior cornea.
The shift of the lens in this case is microns, but this is quite enough to restore vision by 100%.
It is clear that other operations are performed on the eyes, for example, a cloudy spot is removed from the cornea or the clouded lens itself is changed, but these procedures have nothing to do with myopia or hyperopia. This is done in order to restore a person's vision in principle, since in a severe form of cataract, the eyes see almost nothing.
In what cases the operation is not performed
Refractive surgery affects one of the most delicate and fragile human organs, it is clear that there are many contraindications for its implementation.
First of all, the procedure cannot be carried out if the patient has any infectious diseases of the eyes, for example, conjunctivitis. Moreover, the operation is performed only if the patient has not suffered from such diseases within 1 year before the procedure. The eye from this point of view should beabsolutely he althy.
Surgery is not performed if the patient has AIDS or another disease of the immune system. After all, after the operation, natural healing should begin, and in the absence or weak immunity, this is impossible.
If the patient was forced to take drugs with isotretinoin or amiodarone, the procedure is not carried out until all traces of the substances have left the body.
The patient must understand that after the operation, the immune system will be significantly weakened, so all chronic diseases that he has will definitely manifest themselves. So, often after the operation, the patient shows herpes or a similar disease. It is necessary to bring this information to the patient so that he is ready to undergo appropriate treatment after the operation.
Side effects after surgery
Cataract and refractive surgery is still penetration into the structure of the human eye. Naturally, after it there are a number of side effects.
After refractive corneal surgery, there is a sensation of the presence of a foreign body in the eye. Many patients compare this to the effect of getting sand in their eyes.
Eyes are extremely sensitive to light for several hours or even days, patients are forced to stay in dark rooms for a long time or go outside in dark glasses.
Another side effect is a halo around the light source, many people think that the edges of the window opening or frame double. After refractive surgery, it is not uncommon for dry eyes to occur, leading to physicaldiscomfort.
Complications from surgery
Despite the fact that the percentage of complications of refractive surgery is very small, about 1%, but still complications can occur. The patient is informed about this possibility before the operation. Complications include infection in the eye, overcorrection, undercorrection, irregular astigmatism.
But, as already reported, such cases are extremely rare and, as a rule, they occur against the background of the fact that the patient himself did not tell the doctors that he had an autoimmune disease or his eyes were infected shortly before the procedure. That is why the patient's condition before the operation is checked by examining various blood tests. Physicians do not often rely on patient self-reported information.
Laser keratomileusis or LASIK
Modern technologies of cataract and refractive surgery widely use laser equipment. During the LASIK procedure, a piece of the cornea of the eye is cut and processed using a femtosecond laser.
Next, the piece is returned to its place and attached using an excimer laser. The flap takes root the very next day without visible tissue defects. In this case, the refraction effect occurs, and the image is focused on the retina itself, and not in front of it or behind it.
This procedure is distinguished by the absence of infection or infectious lesions, pain syndrome. Already on the second day, the patient can look at the world with new eyes.
To the disadvantages of this methodthe following applies: the cornea of the eye can become so thin that it can no longer withstand intraocular pressure and begins to bend. This, accordingly, will spoil the focus on the fundus, and the person will again see poorly.
This type of operation is used in cases of myopia, hypermetropia and astigmatism.
Photorefractive Keratectomy Surgery - PRK
Refractive eye surgery involves the use of the PRK method. During the procedure, part of the cells of the cornea is evaporated with a laser, after which a new cornea is formed, but with a different curvature. This procedure takes about 3-4 days, while the patient must wear special lenses that hold the cornea all this time. When it is completely fused and healed, the image is fixed on the fundus, which returns vision to 100% clarity.
This procedure is used on those patients who have a very thin cornea, that is, there is a possibility that it will stretch under the influence of intraocular pressure. If a sufficiently large area of the cornea is ablated, then the risk of its partial or complete clouding increases.
Surgery using the method of intracorneal ring segments - ICKS
The essence of this procedure is the implantation of artificial arcuate strips - intrastromal segments - into the anterior part of the cornea. Previously, strips similar in shape are cut out of the cornea. Implants can changethe radius of the cornea bend, which allows you to focus the image at the desired point in the fundus.
This procedure is performed on a patient with not very poor eyesight - from -3 to -1 diopters with myopia. If vision changes due to age or other factors, implants can be changed or removed altogether.
This method is criticized by leading ophthalmologists, as it can cause infection in the eye, there is such an effect as overcorrection or undercorrection, since it is very difficult to calculate the necessary curvature of implants.
Installation of phakic intraocular lenses – IOL
Not all patients are equally suited to laser corneal correction. In this case, a special lens is placed directly in front of the lens or behind it. It is implanted under the cornea, so the operation is quite complicated and is not performed in all clinics. At the same time, there is a high risk of cataracts, glaucoma and other darkening of the lens. Again, there is a high chance of infection in the eye.
Lens extraction
The operation to remove the lens is performed only in the center of refractive laser surgery. Indications for it may be cataracts or hypermetropia. During the procedure, the lens is cut out and an intracorneal lens is placed in its place.
This operation is complicated by the possibility of retinal detachment or destruction of the posterior lens capsule. That is why it is carried outonly in large clinics with modern equipment and professional ophthalmologists. For example, in the center of refractive laser surgery in Yekaterinburg or another big city.
Radial and Astigmatic Keratotomy
This type of operation does not use lasers and other modern techniques. The bending radius of the cornea is changed by making incisions on it with a scalpel. After their healing, the cornea becomes smaller, changes the concentration of the image at the bottom of the fundus. This type of surgery was performed at the dawn of ophthalmology and surgical treatment. Currently, it is used extremely rarely, for a number of contraindications. This type of procedure is also prescribed for cataract removal.
Refractive eye surgery is a modern method of solving vision problems. Similar operations are performed for various diseases of the organs of vision. It is important to observe safety measures during the rehabilitation period. You can not abuse alcoholic products, physically overstrain. All doctor's prescriptions should be observed, otherwise complications are possible that will require additional treatment. In general, such procedures are always successful, with some exceptions, so you should not be afraid.
