What is Lasik?

LASIK, sometimes mistakenly called LASIX, is short for "laser-assisted in situ keratomileusis." It is the most commonly performed refractive surgery procedure -- partly because of the relative lack of pain immediately afterward and partly because good vision is usually achieved by the very next day, if not before.

An instrument called a microkeratome is used in LASIK eye surgery to create a thin, circular flap in the cornea. The surgeon folds the flap back out of the way, then removes some corneal tissue underneath using an excimer laser. The laser uses a cool ultraviolet light beam to precisely remove ("ablate") very tiny bits of tissue from the cornea to reshape it. When you reshape the cornea in the right way, it works better to focus light into the eye and onto the retina, providing clearer vision than before. The flap is then laid back in place, covering the area where the corneal tissue was removed.

Both nearsighted and farsighted people can benefit from LASIK surgery. With nearsighted people, the goal is to flatten the too-steep cornea; with farsighted people, a steeper cornea is desired. Also, excimer lasers can correct astigmatism, by smoothing an irregular cornea into a more normal shape.

In PRK (photorefractive keratectomy), an excimer laser removes tissue directly from the surface of the cornea. Both LASIK and PRK are an improvement over RK (radial keratotomy), a non-laser procedure that involves making incisions in the cornea in a radial pattern. The result is that the cornea is flattened, thereby correcting nearsightedness. Drawbacks to RK include pain, lengthy healing times, regression over time, and scarring in some people. Since the incisions go deeper into the cornea than the laser does, many surgeons consider the surgery more invasive and therefore potentially traumatic to the eye than PRK or LASIK. RK is rarely performed now.

What is the difference between Lasik and PRK?

At LASIK VISION, most patients receive the LASIK (Laser in-situ keratomileusis) corrective procedure. Depending on the health and condition of your eye, PRK (Photorefractive keratectomy) may be a better option. The same excimer laser is used in both treatments.

In the LASIK procedure, before using the excimer laser, surgeons gain access to the bed of the cornea by creating a hair-thin corneal flap in the eye's outer membrane. A delicate, finely tuned automated instrument called a microkeratome makes this flap with exacting precision in a matter of seconds. After lasering the cornea, the flap is replaced and the membrane heals naturally.

In PRK, no corneal flap is created. The surface cells of the cornea are gently polished away allowing the laser to reshape the bed of the cornea. After the procedure, a protective lens is placed over the eye for approximately five days while the surface of the cornea heals. The lens is removed in a follow-up visit.