The excimer laser can correct vision defects by vaporizing cold corneal tissue in a targeted manner. This is performed on the surface with various methods that differ from each other only in the preliminary preparation to the action of the laser:
- PRK: derived in English from Photo Refractive Keratectomy, which in Italian means refractive photo keratectomy. The surgery involves the mechanical removal of a part of the thin membrane surface of the cornea (epithelium) by means of a blunt instrument and subsequently the excimer laser is applied. A more advanced variant of this technique is the transepithelial PRK; in this case the epithelium is removed directly by means of the excimer laser allowing the customization or personalization of the intervention directly on the corneal surface without the need to perform cuts or other invasive surgical manoeuvres.
- LASEK – Laser Epithelial Keratomileusis: The technique involves the lifting of the corneal epithelium. Such lifting is obtained by soaking the epithelium in an alcoholic solution. After the lifting, the epithelium is repositioned on the corneal stroma.
- EpiLASIK: epithelial Laser In Situ Keratomileusis. This technique is also used for the lifting of the corneal epithelium, but unlike the LASEK, the lifting is obtained by the application of a mechanical instrument specifically designed to lift the epithelium, called epikeratoconus. After the lifting is performed, the epithelium is repositioned on the corneal stroma.
- Intrastromal surgical techniques: treatment with the excimer laser in this case does not take place on the surface of the cornea, but within the cornea, specifically on the intermediate layer called stroma.
In order to successfully perform the procedure, it is important to have sufficient practice and experience with surgical instruments such as the excimer laser. The intrastromal technique raises the flap of the corneal tissue and applies the excimer laser in order to reposition the flap. In rare cases, it may be necessary to place some temporary stitches. In other cases, the surgeon may determine that the flap that needs to be cut to be qualitatively inadequate. When this complication occurs, the surgeon may decide to reaffix the flap and delay the intervention for a more appropriate time in the future.
The same method can be carried out in depth, after having cut and raised a superficial layer of the cornea. This technique is called intrastromal LASIK
- LASIK: derived from Laser Intrastromal Keratomileusis, which in Italian means Laser cheratomilesusi interstromal. The stroma is cut with a "micro planer" call microkeratome.
Today flap creation can be realized with a new type of laser, called femtosecond laser, which has improved the safety and reproducibility of the intervention by reducing the potential risk of complications.
Surgeons from the refractive department at the Humanitas Ophthalmology Centre are professionals who are up to date on all kinds of surgical techniques, who posses a considerable amount of surgical experience, and they are able to provide specific measures and parameters that pertain to the type of intervention that is most beneficial to the patient’s disability.