There are several kinds of laser procedures eyes. LaserSjón offers all of them: Lasik procedures, Lasek/PRK procedures and Zyoptix procedures. There are more details on each procedure below.
LASIK is the commonest procedure used to correct defects in vision, such as nearsightedness, farsightedness and astigmatism.
What does LASIK mean?
LASIK is an abbreviation of Laser-in-situ-keratomileusis or Laser-assisted-in-situ-keratomileusis. A laser beam is used to change the shape of the cornea without disturbing adjacent tissue.
- In-situ = in a natural/normal location.
- Kerato = cornea.
- mileusis = to shape.
LASIK procedures have been performed in other countries for about 20 years. The procedure has a longer history, and it can be said that ophthalmologists have been trying to shape the cornea for more than half a century.
Advantages of the LASIK procedure Its main advantages over other laser procedures are:
- Little discomfort to the eyes following the procedure.
- The wound heals quickly.
- The eyesight becomes relatively sharp after a few hours or days.
- Fewer post-procedure examinations are required.
- The visual acuity becomes permanent after several weeks.
Side effects are possible in the procedure, and in their wake, problems can make another procedure necessary. Nevertheless, this seldom happens and rarely involves permanent reduction of vision. In certain instances, retreatment can also be necessary to achieve the set goal.
A special planing instrument is used to cut precisely 120-140 microns into the cornea, creating a corneal flap (or cover) that is later lifted to one side while the laser procedure is performed on deeper layers of the cornea. How much tissue has to be removed depends on the individual; this is calculated precisely from the information obtained during the preliminary examination and entered into the computer controlling the laser equipment. After the procedure, the flap is replaced, and after several minutes it has become "re-glued", making it possible to blink the eye normally. There is little, if any, pain, and the eye heals quickly. The flap later heals completely at the edges, and there is therefore little risk of scar tissue forming, and the vision quickly becomes as sharp as it will be. Some improve their visual acuity by one line, and about 10% lose one line from the best visual acuity. If further correction is required, it is technically easy to do because there is no need to cut another flap.
During a procedure for nearsightedness, proportionally more tissue is removed from the middle than the periphery of the cornea. Its shape is changed, becoming flatter. The refraction is reduced; rays of light meet in the retina, and the vision becomes sharp. The diameter of the laser procedure is limited and thereby the "optical" area. Usually the treatment is 6.5-7.5 mm in diameter, and beyond that the cornea changes little. This can sometimes cause discomfort in darkness. Especially those with naturally large pupils can be dazzled when light shines into their eyes. Light is disbursed creating a halo effect. Some people find this uncomfortable, especially when driving in the dark. During the preliminary examination, the size of the pupil is measured precisely, and those at risk for this are advised against the procedure.
The LASEK procedure is a type of the LASIK procedure performed if the cornea is too thin to cut a flap as is done in the LASIK procedure. The top layer of cells of the cornea (the surface covering) is loosened, and tissue is then removed from the centre with laser beams. How much tissue has to be removed depends on the individual; this is calculated precisely from the information obtained during the preliminary examination and entered into the computer controlling the laser equipment, which then makes precise calculations. The procedure requires a total of 20 minutes, but the laser itself operates less than a minute. The top layer of cells is then replaced over the eye. After the procedure, a contact lens is placed on the eye, a kind of Band-Aid, protecting the wound to the cornea and reducing discomfort. The contact lens is most often removed 2 to 3 days after the procedure. The procedure leaves a wound on the surface of the cornea that heals in several days. The eye pressure increases.??
When LaserSjón opened its doors in 2000, there was only one kind of software for procedures, Planoscann.Also, the laser was set by measuring the relevant eye, like prescribing glasses. All eyes were then treated as if it were only possible to take the pupil size into account in procedures. We all know that one size does not fit all in the real world, and these procedures have not been our first choice in years.
The main progress in refractive procedures the last several years has been improved software. LaserSjón has always had the goal of offering the best and newest treatment. We quickly began offering Zyoptix procedures, which are tailored to each individual eye and take more factors into account than just pupil size.
Emphasis is placed on the size of the procedure with Zyoptix Tissue Saving, where the software records the eye's shape and produces the maximum correction with the minimum scope of the procedure. A smaller procedure increases safety, especially if the corneas are thin. Recording of the eye's shape in the software reduces halo effects and flaring which, turn, improves the quality of the procedure.
There is also software named Zyoptix Aspheric. It emphasizes maintaining the original shape of the eye's surface; this limits the effect of the procedure on the eye's operation under different lighting conditions and has proved very effective.
What we use most is Zyoptics Personalized. This software creates a specially shaped picture of how each eye focuses on the picture (wavefront). We have then come a long way from the "one-size-fits-all" concept. Also, there are no given sizes; rather, each eye is measured separately. The analysis is so precise that the main difficulty is implementing it. How should the laser be programmed to get this particularly precise picture to fall in the right place? To implement this analysis, we take a picture of the eye's iris, which is like our fingerprints; each iris is unique. The laser recognizes the picture of the iris and locks onto its pattern. With this reference, the correction is delivered in the right place (iris-guided wavefront). This program also provides good predictability, i.e., how often the planned correction is obtained.
This software has most changed laser procedures and their outcome in the eight years we have been working. LaserSjón has been in the forefront in the Nordic countries in incorporating this new software. Its successful use builds on our years of experience, for no software can replace experience.