Advantages and disadvantages of Lasik
The great advantage of Lasik is the extensive freedom from pain directly after the operation. Moreover, the desired vision is achieved very quickly (within a few days) and there is only a very low risk of corneal scarring, which in turn would cause discomfort and deterioration of vision. Due to the nature of the procedure – it is an invasive surgical procedure – there are disadvantages of Lasik.
There can be cutting errors and infections due to the invasiveness. In addition, after Lasik there is a risk of epithelial ingrowth, especially at the edges of the corneal flap. In general, another disadvantage of Lasik is the limited applicability of this procedure.
Not all visual defects can be corrected, but there are limits to the strength of the visual defect, since the cornea can only be ablated up to a certain residual thickness. This should not fall below 250μm. For short-sightedness (myopia), this means a limit of eight diopters for Lasik, for long-sightedness (hyperopia) four diopters and for astigmatism six diopters.
Contraindications that do not allow the performance of a Lasik operation include various points. Firstly, it is not performed if the patient’s expectations of the result cannot be met with the help of Lasik. On the other hand, changing, unstable visual defects, age under 18 years, and infections of the eye (for example bacterial or viral diseases) are contraindications for Lasik.
Not only pathogen-related, but also autoimmune-induced inflammations prohibit the use of Lasik. These autoimmune diseases include those of the connective tissue, so-called collagenoses, as these promote the formation of ulcers in the eye (ulcers). Wound healing disorders and the formation of new blood vessels (neovascularization) on the choroid (chorioidea) are also among the contraindications for Lasik, as the latter increase the risk of bleeding during surgery.
Furthermore, Lasik must not be performed on untreated lesions of the retina, as these can be aggravated by the intervention (especially by the suction process) and there is a risk of blindness. Excessive visual defects (see “Disadvantages”) are also among the contraindications, as too much cornea would have to be removed for optimal correction, so that the remaining too thin residue can undergo pathological changes.For example, corneal ectasia can develop, which is characterized by a protrusion of the cornea. Similarly, Lasik must not be performed if there are changes in the deeper corneal layers or if the cornea is less wetted with the body’s own tear fluid. Finally, pregnancy and lack of patient cooperation (incompliance) must be mentioned. For example, the patient must be willing to consistently fix a point during Lasik (eye tracking).
