The primary difference between PRK and LASIK refractive surgery is that in LASIK, the vision correction occurs under an epithelial flap, while in PRK, the vision correction is performed on the surface of the cornea after the epithelium has been removed. The epithelial cells then heal during the following 3 to 4 days, in order to cover the cornea.
Many providers believe that LASIK offers numerous advantages over refractive vision correction performed on the cornea's surface (PRK). There is often a more rapid improvement in vision and decreased discomfort with LASIK, since the surface epithelial cells have been preserved and do not need to heal or regrow. However, there are additional risks associated with the LASIK procedure.
In some patients, PRK is a safer alternative that may promise better outcomes. Patients who might benefit from PRK include those in whom the cornea might be too thin for LASIK, or in some patients with corneal irregularities or scars. Occupational demands may also make PRK a better option because flaps created during LASIK can easily be lifted, even years after surgery.
A brief comparison of PRK and LASIK is outlined in the following chart:
| Item |
PRK |
LASIK |
| Initial examination |
Similar to LASIK |
Similar to PRK |
| Procedural difference |
Surface epithelium removed |
Corneal flap made with microkeratome |
| Excimer laser procedure |
Similar to LASIK |
Similar to PRK |
| Postoperative discomfort |
Variable |
Usually minimal |
| Visual recovery |
Starts improving at three days |
Starts improving at one day |
| Possible side effects |
Glare/halo/ghosting Corneal haze |
Glare/halo/ghosting Corneal flap problems |