LASIK is an outpatient surgery on your cornea (the front refracting surface of the eye) used to treat nearsightedness, farsightedness, and astigmatism. A laser is used to reshape your cornea, so that when light enters your eye, it will be focused to a point on your retina, and you can see clearly. If you are nearsighted, the laser is used to flatten your cornea. If you are farsighted, the laser is used to steepen your cornea.
During the procedure, a flap is first created in your cornea. This flap is typically created with a laser. The surgeon then folds back the flap and precisely removes a very specific amount of corneal tissue under the flap using an excimer laser. The surgeon has programmed the laser prior to your procedure with the amount of cornea tissue to be removed. The flap is then laid back into its original position, and it heals in place.
It is important that anyone considering LASIK have realistic expectations. LASIK allows people to perform most of their everyday tasks without corrective lenses. However, people looking for perfect vision without glasses or contacts, run the risk of being disappointed. More than 90 percent of people who have LASIK achieve somewhere between 20/20 and 20/40 vision without glasses or contact lenses. You should be comfortable with the possibility that you may need a second surgery (called a retreatment or enhancement), or that you might need to wear glasses for certain activities, such as reading or driving at night. Also, you should be aware that LASIK cannot correct presbyopia, the age-related loss of close-up focusing power.