LASER VISION CORRECTION
If you require glasses to see clearly, you are either far-sighted, near-sighted, and/or have astigmatism. To put it simply, when your eyes are trying to put things into focus, they are bending light too much, too little, or unevenly. Laser can be used to neutralize these abnormalities. For example, if your eye is not bending light enough to bring things into focus, a laser can reshape your cornea in order to bend that light properly, resulting in better vision.
There are many types of laser vision correction procedures. The most common ones are LASIK, PRK, and SMILE.
In LASIK, there are two lasers used. The first laser is used to create a clear flap in your cornea. This flap is like a blanket that will cover your cornea after the procedure is done. The flap is lifted to expose the underlying bed of your cornea. Then, a second laser is used to reshape the bed of your cornea. The flap is then returned to its original position, concluding the surgery.
Only one laser is needed, which is identical to the second laser used in LASIK. In PRK, there is no flap created. Instead, the corneal epithelium (the most superifical cells of the cornea) is removed, exposing the corneal bed. Then, the laser is used to reshape the cornea. The epithelium usually regenerates on it's own within 5-7 days.
The cornea is reshaped by having a laser remove a lenticule (a disc or frisbee shape) from the center of your cornea. No flap is needed, and the corneal epithelium does not have to be removed either. This procedure is like liposuction for your cornea. It is reshaped from the inside.