I will begin by stating that I am not a surgeon/ophthalmologist, still I am able to provide some information on this topic as it is an alternative to corrective vision. I'll explain the different in surgeries and advice at least two consults with different ophthalmologist to best determine your desired outcome.
PRK (Photorefractive Keratectomy) is procedure first performed in 1987 in order to correct vision. The laser used has changed throughout the years however the technique has remained the same. Essentially the corneal epithelium (front surface cells) is reshaped to mimic the shape of corrective lenses in your glasses. The cornea, which is made of many layers, is reformed to the best possible shape without increasing complications for the ocular health in the future. PRK lasers the immediate surface of the cornea and enter the stromal cornea (deeper tissue), vaporizing tissue one layer at a time. Following the procedure the patient will be given a bandage contact lens to wear to protect the recently re-shaped tissue (considered an open wound). The recovery is considered more painful and vision is blurred for a longer period of time. Most patients will claim better clarity within two weeks and up to 6 months. With proper post-op care from your doctor the results can be wonderful.
LASIK (Laser assisted in situ keratomileusis) was first performed in 1989 with use of lasers and a microkeratome (creates a perfect cut on the epithelial layer to separate from the stromal cornea). The use of these two instruments allow the surgeon to peel the first couple of corneal epithelial layers, laser only the stromal tissue and replace the epithelium back to it's normal position (epithelium will have a loose attachment post-surgery). As you can guess this will reduce pain and increase clarity post-operatively. This extra loosely attached epithelium is referred to as the flap. Most military facilities will suggest PRK surgery for their pilots, having a flap during a flight can be a huge risk for the pilot's vision.
LASEK (Laser assisted sub-epithelial Keratectomy) is almost exactly like PRK with one difference. The first couple of epithelial layers of the cornea will be peeled back with an alcohol solution to save some healthy surface tissue (this will not create a flap), the laser will only work on stromal cornea. This will reduce the pain and visual recovery will be faster. The procedure is taking the place of PRK and LASIK, however in some cases those are best recommended.
For a list of requirements, complications, systemic contra-indications or more questions simply comment on the bottom of this blog and will forward you more helpful material. Keep in mind refractive surgery isn't a permanent solution to visual discrepancies. The success depends on the stability of your body's changing system, which is unpredictable.
See and Be Seen! at Eyed LA Optometry in Brentwood, West Los Angeles