Today, 45-50% of people over the age of 14 are visually impaired and wear glasses or contact lenses. Fortunately, modern technology makes it possible to fully restore vision with correction in a very short period of time. The cost of the surgery is becoming increasingly affordable, and the feedback from most patients remains positive. What is the nature of the surgery?
What is Laser Vision Correction?
Human vision is a tool that allows us to receive information from the environment. At the same time, more than 80% of information is perceived through the eyes, so even the slightest visual disturbance can cause severe discomfort.
The human eye is an extremely complex mechanism. As light rays pass through the cornea, lens and vitreous body, they are naturally refracted to reach the retina. The signals are then transmitted along the optic nerve to the brain, where they are processed by the appropriate parts of the brain and the person receives a clear image. In nearsightedness and farsightedness, light rays are not focused on the retina, but are collected behind or in front of it, resulting in a blurred image.
The goal of vision correction is to change the refractive power of the eye so that light rays are properly focused on the retina. This is why people wear glasses or contact lenses. However, these methods of vision correction only provide good vision for the duration of their use and do not eliminate the problem of vision loss.
Laser vision correction, or refractive surgery, is a medical procedure that uses advanced laser technology to correct the following conditions:
Unlike eyeglasses or contact lenses, laser vision correction radically solves the problem of reduced vision and no additional devices are required for perfect vision.
Types of Vision Correction
In general, the following types of vision correction are used in health care.
Vision correction is any type of glasses used to improve a patient’s vision or quality of vision. There are now a variety of materials and filters used in the manufacture of eyeglasses.
Contact Correction – Contact correction refers to the use of contact lenses worn directly on the surface of the eye to correct vision.
Surgical Correction – Surgical vision correction refers to any surgical procedure that ultimately improves a patient’s vision. Surgical correction is usually required for a variety of conditions.
Laser vision Сorrection – unlike traditional surgery, there is no direct contact of the instrument with the eye. All operations are performed with the help of a directed laser beam. Three types of laser vision correction are the most common: photorefractive (PRK), LASIK and RELEX SMILE. The main difference between them lies in the implementation of the technique and instrumentation:
1. PRK (PRK) – direct action on the outer surface of the cornea;
2. LASIK (Laser Keratomileusis) – action on the previously exposed inner layer by tangential incision of the surgical instrument and folding of the flap;
3. ReLExSMILE – no flap is created and the inner layers are exposed.
The principles of PRK and LASIK are not in competition, they are complementary: Superficial methods such as PRK are more suitable for correcting nearsightedness and complex astigmatism associated with nearsightedness, while correction of other refractive errors is more effective with methods such as LASIK.
Laser Correction of Various Vision Disorders
Hypermetropia is a condition of the visual system in which the focus is not on the retina but in the plane behind it. As a result, distant objects appear blurry. Farsightedness can occur at any age.
Age-related farsightedness and normal farsightedness are characterized by the same difficulty in focusing on near objects.
Laser correction is an effective way to correct vision for mild to moderate farsightedness.
Benefits of laser surgery for farsightedness:
- Recovery occurs within 1-2 days of surgery;
- Minimal restrictions after surgery;
- Protection of corneal structures;
- Absence of scarring;
- Minimal pain – 2-3 hours after surgery;
- Laser correction of hyperopia is a stable result and long-term refractive effect;
- Hyperopia treatment is recommended for both eyes at the same time;
- Absence of postoperative corneal clouding;
- Correction of high hyperopia, including astigmatism, should be possible.
Nearsightedness or myopia is a disorder of refraction, or the bending of light in the eye. In this condition, an image is formed in front of the retina that requires the eye to focus directly in front of itself to focus on an object. Myopia can be congenital or acquired and usually increases with age.
Myopia surgery is considered cosmetic. This means that there are no absolute indications for it and everything depends on the patient’s wishes, desire for comfort and refusal to wear glasses or contact lenses.
Advantages of laser surgery:
1. safety – according to patients’ observations, this type of surgery is safe and very effective;
2. applicability to a variety of eye diseases – if the patient has no contraindications, laser therapy can help restore good vision in many eye diseases;
3. speed of the surgery – the surgery takes less than 15 minutes;
4. Painless – the patient feels only a touch during the surgery;
5. stable results – if the patient does not have progressive myopia, the correct shape of the cornea is maintained for many years after laser correction.
Astigmatism is a common visual impairment caused by congenital changes in the shape of the cornea. Astigmatism is caused by a deformation of the eye’s two main meridians-the vertical and horizontal. The refractive power of the cornea along its principal axis determines the type of astigmatism:
Direct astigmatism – the maximum refractive power is observed in the vertical meridian.
Inverse astigmatism – the maximum power is observed in the area of the horizontal axis.
Axial oblique astigmatism – the principal meridians do not coincide with the horizontal and vertical axes of the eye due to corneal deformation.
Recently, surgeries to correct astigmatism using laser technology have become popular. Such surgeries are performed in the shortest possible time and with minimal likelihood of side effects. The advantages of laser treatment are the same as for myopia and hyperopia.
Indications and Contraindications for Laser Vision Correction
Surgical correction of deviations from normal vision is prescribed in the following cases:
More than 3 dioptres;
Mixed astigmatism and farsightedness;
Inability to use contact lenses or glasses.
Contraindications to laser vision correction include:
- Unstable refraction;
- Age under 18 years and over 45 years;
- Patients with damage to only one eye;
- Thin corneas;
- Nursing or pregnant women;
- Infectious or psychiatric diseases;
- Autoimmune diseases;
- Diseases of the heart or endocrine system;
- Diabetes mellitus.
Important: Patients for whom laser surgery is contraindicated should be offered alternatives such as lens transplantation, tangential keratoplasty, arcuate keratoplasty, refractive lens exchange, or other surgical techniques.
Laser Surgery and Patient Age
The minimum age for laser vision correction is 18. This is due to the fact that children’s eye tissues go through developmental stages and the refractive properties of the involved eye elements change gradually, reaching a fixed position by the age of 18.
After the age of 45, the lens thickens with age, it becomes more difficult to adapt to optical conditions, the muscles that hold the lens in place weaken, and the ability to focus is lost. Therefore, after the age of 45, after careful diagnosis, surgery is performed for all serious indications, and for people over 55, doctors do not recommend eye surgery at all.