What does it entail?
It is a type of laser that uses ultraviolet light obtained from an excited dimer (origin of the name excimer). In addition to eye surgery, it also has industrial applications.
How accurate is it?
The LASIK technique is extremely accurate thanks to the laser being capable of removing microscopic layers from the corneal wall.
The following example clearly illustrates this phenomenon: The mean corneal thickness removed by the laser to correct one dioptre of myopia is 10-12 microns with the most advanced lasers. Vision is corrected in 0.25-dioptre increments, corresponding to an extremely thin layer just 3 microns thick. A single red blood cell has a diameter of 7-10 microns. This comparison allows us to understand how this surgical technique has taken the biological precision of medical technology beyond all previous limits.
Nevertheless, the cornea is a living tissue with varying degrees of mechanical strength and healing ability. This depends ultimately on the biological, genetic and biomechanical properties of the cornea of each patient.
Therefore, the actual target of these techniques is ± 0.75 dioptres. With this correction, most patients will not need to use glasses or contact lenses for everyday life. In some cases however (less than 10%), the presence of under-correction that significantly affects the patient's quality of vision may be a reason for repeating laser treatment, which tends to be performed after 3-6 months.
At our institution and with the CEM Clinic Excimer Laser, the rate of repeat surgeries ranges between 4 and 6% each year.
Let's talk about Custom Excimer Laser Treatment
This has been a very important improvement. Custom treatments can treat irregularities in the corneal curvature of each eye in an individualised manner. Such treatments use wavefront technology that quantifies the so-called ocular aberrations found with corneal topography. This information is transferred to the laser via computer software so that the laser can help correct corneal irregularities while correcting vision. On our laser platform, this useful technology is called ORCAM.
And let's talk about how many dioptres can be corrected with the excimer laser...
The laser can be used safely to correct up to 8 dioptres of myopia and up to 5-6 dioptres of hyperopia, with or without associated astigmatism. It can also correct up to 5 dioptres of astigmatism. For defects in excess of these corrections, the scientific community and specific use of each laser platform cannot support results as good as those obtained within the aforementioned safety ranges.