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In eyes with normal vision, the cornea bends (refracts) light precisely onto the retina at the back of the eye. However, with nearsightedness (myopia), farsightedness (hyperopia) or astigmatism, the light is bent incorrectly, resulting in blurred vision. Wearing glasses or contact lenses can correct vision but reshaping the cornea itself also will provide the necessary refraction. The reason why Lasik surgery may be an option for correction of nearsightedness is when your eyeball is slightly longer than normal. Farsightedness is when you have a shorter than average eyeball or a cornea that is too flat. Astigmatism is when the cornea curves or flattens unevenly. The Lasik surgery is usually completed in 30 minutes or less using a programmed laser, your surgeon reshapes parts of your cornea with each pulse of the laser beam. A small amount of corneal tissue is removed. Lasik offers improvement of vision without the hassle of glasses or contact lenses in a good chance of achieving 20/25 vision or better after refractive surgery. According to Mayo Clinic, more than 8 out of 10 people who've undergo Lasik refractive surgery no longer need to use their glasses or contact lenses