PRK was invented in the early 1980s. However, unlike LASIK, there is no corneal flap involved. The surface of the cornea is painlessly removed by a blunt instrument or by laser. Subsequently, excimer laser is applied directly to reshape the cornea. The procedure takes 5 to 10 minutes per eye.
This is a FDA-approved procedure for the US military and is used for Singapore Armed Forces personnel.
It is an extremely precise and accurate procedure. Although PRK recovery can take a few days.