The Dawning of A New Era
Since the late 1970s, incisional refractive surgery has treated vision abnormalities in patients all over the world allowing them to experience a new kind of freedom. It's the kind of freedom that allows people to make lifestyle choices that were not options to them before because they were totally dependent on glasses or contact lenses. 1988 marked the dawning of a new era in refractive surgery with the advent of the Excimer laser. For as many as 45% of the population, the Excimer laser could represent the first step towards less dependence on corrective lenses.

The Excimer laser is a computer controlled ultraviolet beam of light that sculpts the cornea into the shape it requires to bring light to focus more directly on the retina , thereby reducing or eliminating a variety of refractive errors . The Excimer laser was invented in the early 1980s and has undergone numerous clinical trials since that time to refine its use and determine its safety and effectiveness. The Excimer laser is now routinely used around the world to treat nearsightedness , farsightedness , and astigmatism .
 
What makes the Excimer such a revolutionary tool?

Laser beams disrupt the molecular bonds between corneal cells with extreme accuracy

Each pulse of the laser disrupts the molecular bonds between the corneal cells with accuracy up to 0.25 microns (or 0.00004 of an inch) which makes it extremely accurate. The more tissue removed, the greater the refractive power of the cornea is altered. Often, only 50 microns of tissue, i.e. about the thickness of a human hair are removed to achieve the proper amount of correction.

The Excimer laser produces a "cool" or non-thermal light beam as most of its heat is dissipated into the air. This makes it ideal for corneal surgery because it eliminates the possibility of thermal damage to surrounding tissue. Its accuracy combined with its non-thermal characteristics provide refractive surgeons with a tool that can deliver more consistent and predictable results than incisional procedures such as Radial keratotomy.

LASIK
LASIK or Laser in-Situ Keratomileusis treats nearsightedness , farsightedness and astigmatism by removing corneal tissue beneath the surface of the cornea. This procedure combines the accuracy of the Excimer laser with the benefits of lamellar Keratoplasty (LK). LK has been performed since 1949 to correct higher levels of nearsightedness and moderate  amounts  of farsightedness. More recently LK was refined by technological advancements of an instrument called a microkeratome that allows the surgeon to fold back a thin layer of cornea. To treat nearsightedness, a second pass of the microkeratome was required to remove corneal tissue from the inner cornea.


a thin layer of the cornea is lifted up with an automated instrument, called a microkeratome

 However, the quality and accuracy of this second pass could not always be achieved.  With LASIK, instead of making a second pass with the microkeratome (as in LK), the Excimer laser removes the proper amount of corneal tissue with much greater accuracy.  How much tissue removed is controlled by the number of pulses and the size and shape of the laser beam. The corneal tissue is then folded back into its original position where it bonds after only a few minutes of drying. No stitches or eye patches are required after the procedure.

"cool" light from the excimer laser reshapes the internal cornea

Since only the edge around the corneal flap needs to heal, visual recovery is rapid and  patients  report  little  or  no postoperative pain. Additionally, there may be less risk of scarring or developing corneal haze . There is also less need for postoperative medications with LASIK than PRK. LASIK treats low to very high levels of refractive errors. However, because of the microkeratome, LASIK carries additional surgical risks.

Are You A Candidate For Laser Vision Correction?

In general, the ideal patient has a healthy cornea, and must not have had a significant increase in their prescription in the last year. People with certain medical conditions or pregnant women may not be good candidates.

Realistic Expectations
The decision to have Laser Vision Correction is an important one that ultimately, only you can make. It is important that you have realistic expectations and that your decision is based on facts, not hopes or misconceptions. The goal of any refractive surgical procedure is to reduce your dependence on corrective lenses . Laser Vision Correction does not always create 20/20 or even 20/40 vision. It cannot correct a condition known as presbyopia, or aging of the eye, that normally occurs around age 40 and may require the use of reading glasses. In fact, people over 40 who have their nearsightedness reduced with surgery may find they need reading glasses after the procedure. Your doctor will provide you with additional information and options.

The First Step
Finding out more about the health of your eye and your refractive errors is your  first  step  toward visual independence. This is accomplished by calling your eye doctor and scheduling a personal consultation. Should your refractive error fall within the range of correction for Laser Vision Correction, more comprehensive tests will be necessary.  This information will help you and your doctor determine which procedure is in your best interest.
 

Comparison of PRK & LASIK

This information is presented to demonstrate the relative differences between PRK and LASIK. Additional factors such as surgeon experience and preference, type of laser, age of patient, amount of correction and clinical protocols may effect these comparisons.