Eye laser corrections have been performed since 1987. The technology and techniques have improved steadily, and today there is a wide range of different methods.
What they all have in common is that the shape of the cornea is modified by a laser. The laser treatment takes only a few seconds and is done with locally anaesthetising eye drops. There is no pain during the treatment. The treatment methods are primarily distinghuished by how they deal with the epithelium, which is a protective tissue covering the outside of the cornea. This results in differences in the kinds of vision corrections that are possible, recovery times, and other considerations.
Only an eye surgeon can advise you on the treatment options that are best for you.
As the technology leader, SCHWIND offers very sophisticated techniques that enable optimum vision correction. This includes aberration-free treatment that corrects vision defects without changing the patient’s accustomed visual impression. Treatment using wavefront data addresses higher-order defects and improves vision quality to the greatest possible extent.
Compare the different types of laser eye surgery:
TransPRK by SCHWIND is the only surface treatment in which the eye is not touched by any instrument. No suction is applied to the eye, and the cornea is not cut. The outermost, regenerating corneal layer (epithelium) does not need to be manually removed, and no alcohol solution is used. Instead, to improve the patient’s vision, the excimer laser models the cornea through the epithelium. The top corneal layer grows back quickly. Since 2009, TransPRK – with SCHWIND AMARIS laser systems – has grown more and more popular. The SmartSurfACE technique combines TransPRK with SCHWIND SmartPulse, a unique technology that greatly speeds healing and provides good vision quality immediately after the treatment.
PRK is the eye lasering method that has been in use the longest, since 1987. Today it is used primarily in cases where the cornea is very thin. In PRK treatment, the outermost, regenerating corneal layer (epithelium) is mechanically removed with a blade or rotating brush. The corneal surface is then modelled with the laser. The epithelium regenerates itself within a week.
LASEK treatment is a refinement of PRK and has been in use since 1999. It combines the advantages of LASIK and PRK in a single procedure. In LASEK, no corneal flap is cut. Instead the outer corneal layer (epithelium) is detached with alcohol and moved to the side. The corneal tissue under it is then modelled with the laser. Afterwards, the epithelium is pushed back into place, where it adheres automatically.
In LASIK, a blade cuts a thin flap in the cornea, which is folded to the side before the laser treatment. The corneal tissue under it is then modelled with the excimer laser. Afterwards the flap is folded back into place, where it adheres automatically. This procedure was first tested in 1990.
Femto-LASIK uses two different types of laser. First, a femtosecond laser is used to cut a corneal flap, which is folded to the side. An excimer laser then models the corneal tissue underneath. After excimer lasering the flap is folded back into place, where it adheres automatically. The first Femto-LASIK procedures were performed in 2000.
For pronounced higher-order defects, also known as aberrations, the doctor can recommend treatment using wavefront technology.
A perfect eye reflects light rays in such a way as to form a smooth wavefront. But no eye is quite perfect, so the reflected light shows a wavefront with an individual pattern. Wavefront analysis detects whether there are pronounced higher-order vision defects. These are measured with the SCHWIND Diagnostic Devices. Corneal wavefront data can reveal even the smallest uneven places on the cornea, comparable to a detailed elevation map. Combining this with ocular wavefront data, meaning the light reflected by the cornea and lens, makes the diagnosis even more accurate. Higher-order defects on the corneal surface are analysed in context with individual deviations in the entire eye. This permits laser treatment that is tailored exactly to that specific eye.
In this technique, developed by SCHWIND, common visual defects like nearsightedness, farsightedness and astigmatism are treated without changing the small higher-order defects that many people have and which do not interfere with good vision. This means that the patient retains the accustomed visual impression, so the brain doesn’t have to go through a learning phase.