Since the late 1970s, ophthalmologists have routinely treated patients with nearsightedness, farsightedness and astigmatism with a number of surgical procedures known as "refractive surgery" This brochure covers the history of refractive surgery and describes the most commonly used procedures performed by refractive surgeons today. Refractive surgery became popular in the early 1980s with several incisional procedures.
Radial Keratotomy (RK) was the most popular. Using microscopic, spoke-like incisions in a 'radial' pattern around the center of the cornea (the outer window of the eye) proved effective in reducing low to moderate amounts of nearsightedness.
Astigmatic Keratotomy (AK) which also uses incisions, was used to correct mild to moderate amounts of astigmatism and is still considered a viable procedure for treating astigmatism today.
Although millions of people enjoyed the benefits of RK, its results were somewhat unpredictable from patient to patient and from surgeon to surgeon.
In the late 1980s, ophthalmologists began using the Excimer laser to reshape the cornea. The Excimer laser emits a cool, ultraviolet light that removes tissue with accuracy up to 0.25 microns per pulse. Clinical trials using the Excimer laser demonstrated that low to high levels of refractive errors could be corrected with extreme accuracy and predictability.
Photo-Refractive Keratectomy (PRK) and Laser In-Situ Keratomileusis (LASIK) are both commonly used today to treat low to high levels of nearsightedness, farsightedness and astigmatism. Over one million of these Excimer laser procedures are performed every year with minimal complications and side effects. The primary difference between the two procedures is that PRK treats the surface of the cornea while LASIK treats the inner tissue of the cornea. This requires the surgeon to make a protective flap, which is folded back while the laser is applied. LASIK has become the more popular of the two procedures because removing tissue under the protective flap makes LASIK virtually painless and speeds the healing time. Most people having LASIK see well enough to drive without glasses or contacts the very next day.
Intacs™ micro-thin prescription inserts, were introduced in the late 1990s for the treatment of low to moderate levels of nearsightedness.
When these micro-inserts are placed between the layers of the cornea, the central cornea flattens, thereby changing the cornea's focusing power and correcting nearsightedness. Intacs leave the central optical zone of the eye untouched and have the unique advantage of being removable should y our vision change or another refractive procedure become a more viable choice for you in the future.
Laser Thermal Keratoplasty (LTK), for the treatment of low to moderate farsightedness, has recently been introduced. Without physically touching the eye, two rings of laser energy are applied outside the central optical zone. This shrinks the collagen tissue of the cornea causing it to steepen and increase its focusing power. LTK only takes about three seconds. It is performed on people over the age of forty who currently depend on reading glasses and/or whose farsightedness has progressed to the point that they can no longer focus at distance or near.
LTKs effect may diminish over time and may require re-treatment. This could be comparable to cosmetic procedures designed to reduce wrinkles which over time, may reappear.
All of the refractive procedures mentioned so far involve changing the shape of the cornea. For those who have severe refractive errors or who are in their 5Os or 60s, several other refractive surgeries involve placing artificial lenses inside the eye, Phakic IOLs and Refractive Lensectomy.
Phakic IOLs are intra-ocular lenses that are placed inside the eye, in front of the eye's lens. For younger patients this allows the lens inside the eye to continue its role of helping the eye focus both near and far. This is called accommodation.
Refractive Lensectomy is similar to cataract surgery. As we age, the lens inside the eye losses its ability to focus both near and far. Just as in cataract surgery, refractive lensectomy involves removing the eye's natural lens and replacing it with an artificial lens specific to y our prescription. These artificial lenses can be fixed focus or multiple focus lenses.
It is very likely that more than one of these procedures would reduce or eliminate y our dependence on glasses or contact lenses. However, every eye is different and everyone has different needs. Your first step is to have a thorough eye examination to determine the health of your eyes. Together, you and your doctor will determine which option is best suited for your eye condition and lifestyle.
The decision to have one of these refractive procedures is an important one that only y ou can make. It is important that you have realistic expectations and that your decision be made on facts, not hopes or misconceptions. The goal of any refractive surgical procedure is to reduce your dependence on corrective lenses. Your doctor cannot guarantee your results. You will be provided with additional information about these procedures that will allow you to make an informed decision prior to giving your consent for surgery. Be sure all your questions are answered to your satisfaction before proceeding.