The PRK technique
The PRK technique differs from LASIK in that in this case the laser beam is used to modify the surface of the cornea.
The PRK procedure
The eye surgeon removes the epithelium, the most superficial layer of the cornea. Then using the excimer laser he sends a special ultraviolet light (the laser beam) onto the cornea itself, to ‘carve it’ and flatten it. The laser beams disintegrate and vaporize the tissues they impact (this phenomenon is called ablation), and they create a new shape that allows the images on the back of the eye to be sharp and not blurred.
It is clear that this type of procedure must be performed with extreme precision, at a preset depth and on well-defined micro-areas of the cornea. We are talking about zones that measure in the region of thousandths of millimeters, a dimension that would be unthinkable with a manual technique. In actual fact, the machine performs the ablation, with the exception of the initial step for removing the epithelium; however, the specialist sets the parameters on the machine and controls that every phase is completed correctly
The post-operative clinical progression
In the hours immediately after the procedure, the patient may feel pain, that may be intense at times. Weeping, discomfort in light and a certain degree of burning are frequently perceived. The pain can be controlled with analgesic drugs and by applying a special therapeutic contact lens at the end of surgery; this will be removed five or six days after surgery. Anatomic healing (that is, the healing of the wound created when the epithelium is removed and by the laser ray) will be complete within three to five days.
Only when the normal appearance of the corneal surface has been restored will vision start to sharpen. Total sight recovery requires a longer period of time (one or two weeks); however, full stability of sight may take a few months.
