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LASIK
Refractive Surgical Options
Before choosing the method of refractive surgery that's best for you, it's important to understand the differences between the various correction options.
Photo-Refractive Keratectomy (PRK)
PRK was the first FDA approved method of reshaping your cornea utilizing the precision of the excimer laser. Ultraviolet light and high energy pulses lasting only billionths of a second disrupt the molecular bonds between the corneal cells with accuracy up to 0.25 microns. The excimer laser is unique in that it emits a "cold" or non-thermal light beam. This makes it ideal for corneal surgery because it minimizes the possibility of thermal damage to surrounding tissues. With its computer-controlled precision, the excimer laser represents an important new tool for treating refractive errors.
The excimer laser removes microscopic amounts of corneal tissue from the surface of the cornea, making the central zone flatter. The flattened cornea is then able to focus light more directly on the retina, thereby reducing nearsightedness. The procedure itself typically takes less than 60 seconds of actual laser time. In the United States, PRK has been approved to treat nearsightedness, farsightedness and astigmatism.
Laser Assisted in-Situ Keratomileusis (LASIK)
LASIK (Laser In-Situ Keratomileusis) combines the precision of the excimer laser delivery system with the benefits of Lamellar Keratoplasty. Nearsightedness, farsightedness and astigmatism can be treated with LASIK. First, a thin layer of the cornea, or corneal flap (which looks a lot like a contact lens), is lifted up as the microkeratome glides across the cornea. Then, in less than 60 seconds, ultraviolet light and high energy pulses from the excimer laser reshape the internal cornea with accuracy up to 0.25 microns per pulse. After the tissue has been reshaped, the flap is replaced in its original position. Because of the cornea's natural bonding qualities, healing is rapid and does not require stitches. The entire procedure typically takes less than 5 minutes.
LASIK is a virtually painless procedure with rapid visual recovery, usually within 24 hours. The risk of complications such as infection, corneal flap irregularities, or persistent decreased vision are low and are very surgeon-dependent. Because a protective corneal flap is created during the LASIK procedure, a wide range of prescriptions can be treated and the results long term are quite stable.
Radial Keratotomy (RK)
RK was first performed in the 1930s. Over the past two decades it has been refined into a proven and effective way to correct nearsightedness. RK is performed by making a number of tiny, precise incisions on the outside portion of your cornea, leaving the central cornea untouched. This causes the central cornea to flatten, allowing light to focus more directly on the retina, thereby reducing nearsightedness and your dependence on glasses or contacts. Since the incisions are made with a very thin diamond blade, they are invisible to the naked eye after surgery. The use of RK has fallen dramatically since the introduction of the eximer laser.
Astigmatic Keratotomy
AK first performed in the late 1800's, can be viewed as a modified form of Radial Keratotomy. Astigmatism occurs when the cornea is shaped like a football, more curved in one direction than the other. Light entering the cornea focuses on more than one point within the eye resulting in blurry and distorted vision. Astigmatism is often found in combination with nearsightedness and farsightedness.
During the AK procedure one or two incisions are made in the steepest (or more curved) part of the cornea, causing it to relax and become more round like a basketball, instead of its original football shape. Astigmatic Keratotomy is often performed in combination with other refractive procedures.
Intacs Corneal Ring
Intacs is the first non-laser surgical treatment for people with low to moderate levels of nearsightedness. The FDA granted approval on April 9, 1999. Intacs involve an incision in the deeper structure of the cornea (outside the pupil area) and then placing a plastic ring in the incision. The procedure is most effective in correcting mild nearsightedness.
Intraocular Lenses (IOL's)
IOL's are tiny plastic lenses that are placed inside the eye to help reduce high amounts of nearsightedness or farsightedness. IOL's have been used for years to correct vision after removal of a cataract (a cloudy lens which typically develops in older individuals). IOL's are currently under investigation as a possible alternative to treat high corrections. This type of refractive surgery differs from the above procedures (which work on the outside surface of the eye, i.e. the cornea) in that it involves surgery "in the eye".
Contact us to determine which refractive surgical procedure is right for you.
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Related Links: 1. LASIK 2. LASIK Q&A 3. Refractive Surgical Options |
Laser Assisted in-Situ Keratomileusis (LASIK)
Radial Keratotomy (RK)
Intacs Corneal Ring
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