LASIK is a surgical procedure that uses a laser to correct nearsightedness, farsightedness, and/or astigmatism. In LASIK, a thin flap in the cornea is created using either a microkeratome blade or a femtosecond laser. The surgeon folds back the flap, then removes some corneal tissue underneath using an excimer laser. The flap is then laid back in place, covering the area where the corneal tissue was removed.

The cornea is a part of the eye that helps focus light to create an image on the retina. It works in much the same way that the lens of a camera focuses light to create an image on film. The bending and focusing of light is also known as refraction. Usually the shape of the cornea and the eye are not perfect and the image on the retina is out-of-focus (blurred) or distorted. These imperfections in the focusing power of the eye are called refractive errors. There are three primary types of refractive errors: myopia, hyperopia and astigmatism. Persons with myopia, or nearsightedness, have more difficulty seeing distant objects as clearly as near objects. Persons with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects. Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. Combinations of myopia and astigmatism or hyperopia and astigmatism are common. Glasses or contact lenses are designed to compensate for the eye's imperfections. Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery. In LASIK surgery, precise and controlled removal of corneal tissue by a special laser reshapes the cornea changing its focusing power.

The Lasik Procedure

LASIK (Laser-In-Situ Keratomileusis) is currently the most common type of laser vision correction procedure. It is an extremely effective outpatient procedure that is suitable for low, moderate, and higher prescriptions. It can be used to correct severe prescriptions, and is currently one of the most commonly performed healthcare procedures in North America.

Although no medical procedure is perfect, the Excimer Laser allows for an unparalleled degree of precision and predictability. Each pulse of the laser can remove 39-millionths of an inch of tissue in 12-billionths of a second. This enables an experienced surgeon to achieve remarkable accuracy while maintaining excellent control throughout the procedure.

The Excimer Laser

The Excimer laser is an ultraviolet laser, which utilizes Argon and Fluorine gas to create a non-thermal, or cool beam, of laser light, which can break molecular bonds in a process commonly referred to as"photoablation". A simple way to imagine how the laser works is to think of it as placing the curvature from your glasses or contact lenses onto the front surface of your eye, allowing you to see without corrective eyewear.

The most important aspect of the excimer laser is its remarkable precision. It is able to remove 0.25 microns of tissue in a single pulse; that is, 1/200th of a human hair, 1/40th of a human cell, or 39 millionths of an inch in 12 billionths of a second!