PRK is used to correct or reduce myopia (shortsightedness or nearsightedness), hyperopia (longsightedness or farsightedness), and astigmatism. The PRK procedure flattens part or all of the cornea which in turn allow focal point of light to focus more closely on the retina. PRK differs from Lasik in that it does not create a permanent flap in the cornea, instead it uses the excimer laser exclusively from start to finish, essentially scraping the top level of the cornea. The benefits of PRK is that it is simple and non-intrusive as compared to lasik. As with all surgery there can be complications.