Astigmatism: is it subject to laser vision correction?

Astigmatism (non-compliance) is an extremely troublesome visual defect, manifested not only by a lack of visual acuity both near and far, but also by a crooked and wavy image and poor contrast. If it accompanies short- or farsightedness (hyperopia), selecting optimal corrective glasses or contact lenses is a major challenge.

How an astigmatic sees

An astigmatic is unable to catch focus, has an impaired sense of space, and blurred vision makes daily activities very difficult. Symptoms from the optical system are often accompanied by headaches and dizziness, burning and watery eyes – especially if trying to catch focus by constantly squinting them, and trouble concentrating.

Where astigmatism comes from

Doctors are unable to pinpoint the cause of astigmatism unequivocally. In some it is a congenital, genetically determined defect, in others it appears at puberty or even earlier. It can also happen that astigmatism arises as a result of an eye injury.

Astigmatism has not one name. Ophthalmologists and optometrists use different divisions of astigmatism because it is a defect that can occur in varying degrees of complexity and severity. In the most general terms, we speak of astigmatism when there is a defect in the structure of the eye. A properly built eyeball is spherical. People struggling with astigmatism have a cornea with a more elliptical shape – similar to a rugby ball or an egg. This causes photons of light to enter the eye through two points (sometimes even more…), rather than one, and they cannot focus on a single point on the retina, which is what happens in an eye with a normal structure.

Astigmatism is a refractive defect of the optical system of the eye, which is responsible for the fact that about 50% of patients diagnosed with it experience such a significant impairment in the quality of vision and related comfort of daily functioning that they require ophthalmological assistance.

Not just glasses and contact lenses

Astigmatism correction always begins with an attempt to select corrective eyeglasses (they are called cylindrical) or contact lenses (they are called toric). In uncomplicated cases of regular astigmatism (the magnitude of the defect is equal to the difference in refractive power between the two main cross sections, with the greatest and least refraction, which form a right angle with each other) such correction is sufficient. However, if we are dealing with complicated, irregular astigmatism (there are no main cross sections crossing at right angles or there are more than two of them) and/or accompanied by other visual defects (myopia, hyperopia) or eye diseases (such as cataracts) glasses or contact lenses may not be sufficient. Then it is worth considering laser correction of astigmatism. Besides, it is also worth considering if you have uncomplicated astigmatism, but feel uncomfortable in glasses or contact lenses – up to 99% of cases of such astigmatism are laser-correctable defects.

Methods of laser correction of astigmatism

Regardless of whether we are dealing with astigmatism that is less or more complicated, qualification for surgery for its laser correction is always preceded by precise diagnostic tests. The latest technologies make it possible to combine laser surgery for short/long-sightedness with simultaneous removal of astigmatism – as part of laser vision correction, it is possible to cure astigmatism up to about 6 diopters.

If astigmatism and cataracts co-occur, it is possible to implant toric artificial intraocular lenses and get rid of both problems at the same time.

Laser correction of astigmatism is most often performed by methods:

LASIK (laser assisted in situ keratomileusis) – the cornea is incised with a scalpel (microkeratome), and then the corneal surface is modeled so that it can properly focus the image onto the retina.

LASEK/PRK – The procedure involves either deflecting (LASEK) or removing (PRK) the upper cellular layer of the cornea (epithelium) and then appropriately reshaping the underlying corneal tissue using an excimer laser. The goal of the procedure is to properly model the central surface of the cornea with a laser beam so that it focuses the image precisely on the retinal surface.

Femto-LASIK (All-Laser-LASIK) – using a precise femtosecond laser, the surgeon makes a cut in the cornea, creating a thin flap 0.1 mm thick – a flap. He uses an excimer laser to reshape the previously exposed cornea for a few seconds, then the flap is closed back up; it attaches and forms a protective corneal barrier.

Laser vision correction is performed under local anesthesia in an outpatient setting. Depending on the method chosen, the patient may experience more or less, but short-term discomfort after the procedure – not during it. After the procedure, it is necessary to follow the doctor’s instructions, about which more here: https://swisslaser.pl/laserowa-korekcja-wzroku/co-to-jest-laserowa-korekcja-wzroku/