Photorefractive Keratectomy has been used since 1986 for the correction of nearsightedness of up to -6 diopter and astigmatism of up to 3 diopter.

In PRK, the excimer laser is used to flatten the corneal tissue. The center of the cornea has a thickness of approx. 0.5mm, and the outer edges measure approximately 1.0 mm. The Excimer Laser is used to remove approximately 0.1 mm from the central corneal tissue thus correcting the refractive error.

The disadvantages of PRK consist of the slow postsurgical healing process and the sometimes very noticeable postsurgical pain.

The LASEK method has been developed from the PRK procedure, where structures of the corneal surface are ablated. With the LASEK, the corneal epithelium (the outer corneal surface of the eye) is separated with alcohol and rolled back, then the PRK procedure is performed, afterwards the epithelium is rolled back and covered with a therapeutic contact lens.

There are less postoperative patient complaints - pain, vision fluctuations - than compared to the older PRK method, in which the corneal epithelium had been removed. To date, no scientific studies have been made to investigate whether this new method leads to the same problems during the healing process such as scarring and regression (reappearance of the refractive error).

At the time, LASIK - laser ablation in the stromal bed of the cornea without ablation on the corneal epithelium - became the method of choice in order to avoid the aforementioned effects. Currently, LASIK is state-of-the-art.

If it is necessary to perform a PRK procedure today, it is done with the LASEK method.