Laser vision correction did not first begin with LASIK but began as a surface-based procedure known as PRK (Photorefractive Keratectomy) back in 1992. Since then, the surface-based procedure has evolved and improved though the years as a result of doctors searching for ways to minimize or avoid the pitfalls of LASIK.
Today, laser vision procedures that are surface-based are collectively grouped and given the scientific name of Advanced Surface Ablation (ASA).
Here is a road map showing the progress of Advanced Surface Ablation (ASA):
EARLY PRK was first done in 1992. However, it did not take off as the excimer laser used back then was first generation lasers that tend to overheat the cornea surface. Also, bandage contact lens and the current eye drops to prevent eye pain, swelling and scarring were not available then.
ADVANCED PRK was a major upgrade from early PRK with the use of the more advanced generation excimer lasers, equipped with active eye tracking and sophisticated laser ablation profiles. NSAID pain-killing eye drops, anti-scarring MMC (Mitomycin-C) medications and high oxygen permeability bandage contact lenses are additional improvements.
TransPRK is now the frontier of Advanced Surface Ablation (ASA) techniques. It is an ideal surface-based procedure as only a single laser removes the epithelium cells and then goes on to reshape the cornea tissue stroma to correct refractive error in one seamless and efficient step.