In PRK, the outer layer ("epithelium") of the cornea is removed chemically, and the laser ablates the surface of the eye. Over a few days the layer grows back.
For LASEK, the outer layer of the cornea is peeled away. The laser ablates the surface of the eye, and the skin is pushed back into place.
For both of these, there is no flap. The cornea retains its original structural integrity. PRK and LASEK are quite similar in process and outcome. PRK is a faster procedure and gives the patient less discomfort. LASEK has a slightly lower risk of corneal haze.
Having experienced both... I'd never choose LASEK again.
It's the same thing with a different marketing name. PRK / LASEK is much more painful (1 week of pain over 36 hours), but has fewer complications, especially for martial artists.
