Spectacles and contact lenses two standard methods of dealing with refractive errors. Both suffer from some problems.
Spectacles are inconvenient, they need to be cared for. On some people, they have poor cosmetic appeal. Images seen from spectacles are different than the actual size, and the objects get magnified or minified based on the type of refractive error. They cause a loss of peripheral vision. For all these reasons and more, some people find wearing spectacles to see clearly an unappealling idea.
Contact lenses solve some of these issues, but they have problems of their own. They can cause dry eye, and significantly expose the wearer to infection. They need to be cleaned and cared in a very correct manner, which can be both inconvenient and expensive. Finally, most people become intolerant to contact lenses over a period of time.
Ophthalmologists have for long struggled to develop a more permanent way of treating refractive errors. While a myriad variety of procedures have been developed to treat refractive errors, the safest, most effective and most popular method by far is LASIK performed with the Excimer Laser. In special circumstances, you may be better suited to other laser vision correction procedures, like PRK or LASEK.
In LASIK, the refractive error is corrected by appropriately reshaping the cornea to change its curvature, and hence, its focusing power. The Excimer Laser is used to perform this reshaping, by appropriately removing microscopic amounts of tissue. The excimer laser was originally developed to etch microchips. Soon, its ability to precisely sculpt human tissue, particularly corneal tissue, was uncovered. The Excimer laser is a cool laser, which does not heat corneal tissue. It breaks inter-molecular bonds within 0.5 microns of corneal tissue, leading to that tissue getting removed from the cornea. It leaves behind extremely smooth surfaces.
Excimer Laser light, controlled with computer precision, gently pulses to remove a microscopic amount of tissue from specific areas of the cornea. This changes the curvature of the cornea, allowing images to be more sharply focused on the retina.

The beam of light vaporizes microscopic amounts of tissue as it breaks inter bonds. Each pulse of the laser removes .25 microns of tissue or 1/39 millionths of an inch. This allows the cornea to be re-sculpted into a more desirable shape, gently and precisely.