LASER VISTA was Switzerland’s first laser eye centre to offer Femto-LASIK for the correction of defective vision using an optical laser.
The area of application is basically identical to that of classic LASIK. It is, however, possible that one eye cannot be considered for LASIK.
The Femto-LASIK procedure is identical to that of classic LASIK. The only difference is in the preparation of the corneal flap. In classic LASIK, this is cut with the microkeratome (small cutting blade), while in Femto-LASIK, it is cut with the femtosecond laser. Both the femtosecond laser and the excimer laser are triggered via a computer.
1. Preparation of the corneal flap using the femtosecond laser
Integrated software allows the surgeon to determine the desired position and dimension of the flap. At the beginning of surgery, a fixation ring is placed on one eye. A glass disc is placed on the ring and, using computer control, the laser rays are focused through this glass disc to a pre-calculated corneal depth. In this process, slight pressure is briefly applied to the eye.
The energy of the femtosecond laser penetrates the outermost layer of the cornea until it reaches the point that was exactly defined in advance. The femtosecond laser now works like a scanner from one corneal edge to the opposite one. The laser ray produces a line of tiny air bubbles in a single plane at the desired depth. Like with classic LASIK, the corneal flap can then be lifted using these air bubbles and folded to one side. By means of the surgical microscope and a monitor, the surgeon can follow the progress of the laser incision precisely. Once the anterior corneal flap has been completely prepared, the fixation ring is removed. The same procedure ensues for the other eye.
2. Correcting defective vision (with the excimer laser)
The corneal flap in the first eye is now flipped open using a delicate instrument. Like with conventional LASIK, the defective vision (near-sightedness, far-sightedness and astigmatism) is now corrected by means of ablation of corneal tissue using the excimer laser.
3. Repositioning of corneal flap and healing
Finally, the corneal flap is folded back into its original position. It bonds itself back into place naturally and seals the cornea like a plaster produced naturally in the body. Laser treatment of the other eye then ensues.
In the first hours, the eye waters and itches a little, and vision is still blurred. Just a few hours after Femto-LASIK, a good level of vision is achieved, although it takes 4-8 weeks to obtain the final level of stability.
The Femto-LASIK procedure is the first time that a laser eye intervention is performed using only lasers, i.e. without the use of a mechanical device (microkeratome).
Femtosecond lasers work with ultra short light pulses that only last for several millionths of a billionth of a second (10-15 seconds). They are able to treat materials in an extremely precise manner and with markedly lower thermal stress than other lasers – which is a great advantage in, for example, ophthalmology and dentistry.
