PRK and LASEK differ from LASIK in that the laser is applied to the surface of the cornea directly. PRK and LASEK use different approaches, yet a hybrid technique works best. PRK laser vision correction was first approved for use in the United States in 1995. While the techniques for performing PRK (photorefractive keratectomy) have evolved significantly over the past two decades, the original form of PRK involved “scraping” the microscopically thin skin layer, known as the “epithelial layer,” off the surface of the eye. The excimer laser was then applied to the eye and a patch was put over the eye until the skin had re-healed. This original method of performing PRK was quite painful for patients.
As PRK evolved over the next several years, a new variation of PRK appeared called “LASEK” with the goal of improving comfort. With LASEK (laser epithelial keratomileusis), instead of scraping away the skin layer, the surgeon simply slid the skin layer off to the side. The excimer laser was used to scupt the tissue and then the skin layer was re-slid back into position over the lasered area, similar to a LASIK flap. The hope was to provide quicker and more comfortable healing than seen with PRK.
Through my own clinical research and clinical experience, I have found advantages and disadvantages to each approach. With PRK, the epithelial layer is removed and allowed to grow back. This is more natural in terms of healing than restoring a previously removed layer of skin and asking it to heal in place. I have found healing is more predictable this way.
On the other hand, the LASEK method of sliding the epithelial flap to the side does create a much smoother surface to apply the laser to, which makes for better optical results. It is also more comfortable for the patient than simply “scraping” away the skin as was originally done with PRK. On the other hand, I have found that repositioning the epithelial flap after the excimer laser has been applied creates more inflammation and discomfort for the patient than simply removing this microscopically thin flap and letting this ultra-quick healing skin layer grow back physiologically.
For this reason, today I combine aspects of both classical PRK and classical LASEK. I use a LASEK removal technique to slide the epithelial skin layer off to the side before applying the laser. I then remove this skin layer, knowing it will grow back quickly over the lasered area. After the laser is applied, I then apply a high technology bandage contact lens on top of the cornea to protect it and to allow the skin to heal physiologically. I have found this approaches provides the most predictable healing, the best comfort, and the most optimal results.
Because there often is confusion between PRK, LASEK, and other techniques such as epi-LASIK that all differ in how the epithelial skin layer is removed, some surgeons prefer simply to use the term “Advanced Surface Ablation” or ASA. This really is an umbrella term that could refer to any of these techniques or hybrid version of techniques. All differ from LASIK laser eye surgery because no true LASIK flap is made — instead the laser is applied directly to the surface of the cornea to reshape it and the skin layer ultimately is restored.
See Also
Laser Eye Surgery For Refractive Errors
LASEK vs PRK for the Correction of Myopia
Postoperative Pain after Epi-LASIK, LASEK, and PRK
LASEK for Myopia: Two Year Follow Up
LASEK vs LASIK for High Myopia Correction
Silicone Hydrogrel Soft Bandage Contact Lens for LASEK and PRK laser eye surgery
LASIK vs LASEK vs PRK: Advantages and Indications
Advanced Surface Ablation Compared to Sub-Bowman’s Keratomileusis LASIK