Laser vision correction allows to completely eliminate or reduce the need to wear eye glasses or contact lenses. The first attempts of vision correction were taken already in the fifties of the last century, although the beginning of refractive surgery is considered in the 70s of the last century. The answer to the search for a safe method of vision correction was the laser, which was introduced on a permanent basis into refractive surgery in the 80s of the last century. Today, the vision correction uses excimer laser and femtosecond laser, while the laser correction itself is worldwide recognized as a safe, effective and predictable method of vision correction.
The essence of correction
Laser vision correction is based on simple principles of optics. In the normal eye ball, the cornea refracts light rays so that they focus on the retina. In the eye with disorders, for example with hyperopia or myopia, refracted light rays fall behind or in front of the retina, resulting in the blurred vision generated. Laser vision correction involves reshaping the cornea so that light rays refracted by it fall on the retina. Computer-controlled laser changes the anterior curvature of the cornea. Modelling of the cornea with a laser contributed to increase the precision and safety of vision correction.
This way myopia, hyperopia and astigmatism can be corrected.
The optical system of the eye is too strong, the light rays are focused in front of the retina. Laser correction will weaken it by flattening the cornea.
The optical system of the eye is too weak, the light rays are focused behind the retina. Laser correction will strengthen it by steepening the cornea.
As a result of an abnormal curvature of the cornea or the lens, light rays are focused at different points, resulting in blurred vision. Laser correction will compensate the curvature of the cornea and make the rays focus at one point on the retina.
In standard, a laser vision correction relates to:
- nearsightedness from -0,5 D to -10,0 D
- farsightedness from +0,75 D to +4,0 D
- astigmatism to 5,0 D.
Laser vision correction operations performed in patients over the age of 21, with an already stabilised visual impairment.
Laser correction of visual impairments does not eliminate presbyopia. Due to an age-related loss of elasticity of the lens, the eye loses its ability to accommodate, that is the ability of a good vision at both far and close distances. So in people over the age of 40-45 there is a need to wear reading glasses, unless the presbyopic profile, LBV, could be possible to perform.
Contraindications for performing laser correction of vision impairment (general diseases): diabetes, connective tissue diseases (the so-called collagenoses), e.g. rheumatoid arthritis, lupus, scleroderma, polyarteritis nodosa, Sjögren’s syndrome, autoimmune diseases (e.g. some thyroid diseases, Hashimoto’s thyroiditis, Graves’ disease), diseases with the weakening of immunity in the course, atopy and severe allergies, as well as acne rosacea (rosacea), active infectious diseases, individual tendency to form hypertrophied scars called keloids, implanted pacemaker.
Contraindications (eye diseases): viral keratitis, herpes zoster ophthalmicus, keratoconus or other corneal degenerations, dry eye syndrome, vascular diseases of the eye, degenerating high myopia, nystagmus.
Laser correction cannot be performed also in pregnant women and breastfeeding women.