What Is LASIK?
Laser in situ keratomileusis (LASIK), which evolved from earlier refractive surgery techniques, such as photorefractive keratectomy (PRK), is an outpatient surgical procedure to reduce myopia (nearsightedness), hyperopia (farsightedness) and astigmatism. It does this by reshaping the cornea, the clear covering of the front of the eye.
How LASIK Works
An instrument with a cutting blade called a microkeratome is used to create a thin, circular flap in the cornea that is lifted. An excimer laser, using a cool ultraviolet light beam is then used to remove("ablate") tiny bits of tissue from the surface of the cornea to reshape it in such a way as to improve vision. The flap is then replaced over the treated area.
Who Is a Candidate for LASIK?
The best candidates for LASIK are those with low-to-moderate nearsightedness or astigmatism. Those who expect perfect vision from LASIK may be disappointed. For example, most people who have LASIK will need reading glasses as they get into their 40s and 50s. Although only your eye doctor can determine if the procedure is right for you, if you have any of the following conditions, you may not be a candidate for LASIK:
Pregnant or breastfeeding
Some autoimmune disorders (i.e. rheumatoid arthritis, lupus, HIV/AIDS)
Chronic use of Prednisone pills or drops
Irritation of the eyelids with itching and scaly skin
Pupil size over seven millimeters
Genetic or metabolic problems that affect the cornea
Warped (from wearing rigid contact lenses) or thin corneas
More than -14.00 diopters of myopia, more than 6.00 diopters of astigmatism or more than +6.00 diopters of hyperopia, which represent FDA limits on approved procedures
Poor night vision, or glare driving at night
An unstable prescription
Rigid contact lenses should be discontinued three to six weeks before pre-LASIK eye examinations since they can change the shape of the cornea over time and surgeons prefer to perform refractive procedures on a cornea that has returned to its natural shape. This helps to determine a more predictable result. In addition, recent research suggests that patients using the common acne medication Accutane (isotretinoin), which has been found to cause dry eye, should stop using the drug at least six months before undergoing LASIK and for six months after the procedure to give the cornea time to heal.
What Are the Risks?
Like any surgery, LASIK does have some risks that need to be considered. The most common side effects of LASIK include:
Changing and blurry vision
Light sensitivity and glare
Undercorrection or overcorrection (It is not possible to predict exactly how an individual's eyes will respond to surgery, so corrective lenses may still be needed after the procedure.)
Nighttime haloes and "starbursts" around lights
For most people these side effects resolve or decrease with time. Approximately 5 to 15 percent of patients return for enhancements. Rare sight-threatening complications of LASIK, include corneal infection or inflammation, problems (i.e., delayed healing) with the "flap," foreign matter (such as dead cells) under the flap, and permanent vision loss.
What Is "Bladeless" LASIK?
In clinical studies, newer technology known as IntraLase, which uses a laser rather than a blade to cut the flap, has been associated with fewer flap and overall LASIK complications. However, refractive surgeons have recently reported one postoperative complication that is unique to IntraLase LASIK-unusual light sensitivity such as photophobia. Proponents of the procedure argue that this complication is temporary and can be resolved with steroid treatment (eye drops). In addition to the potential for fewer flap complications, possible advantages of IntraLase over traditional LASIK include reported lower incidence of post-operative dry eye, and the fact that people with thin corneas who were never LASIK candidates as well as those who have undergone previous corneal surgeries such as radial keratotomy (RK) may now be able to have the procedure. IntraLase, or "bladeless" surgery as it's often called, is more expensive than traditional LASIK .
What Is Wavefront LASIK?
Also known as "custom" LASIK, wavefront LASIK uses three-dimensional measurements of how your eye processes images to guide the laser in reshaping the cornea, allowing for some extremely precise, individualized vision corrections that would be impossible with traditional LASIK. For example, wavefront technology has the potential to improve not just how much you see, but also how well you see in terms of contrast sensitivity and fine detail, reducing the chances of night-vision disturbances and glare. Because of its scientific approach that takes much of the guess work out of LASIK, many surgeons believe that wavefront LASIK is the safest approach. Like IntraLase, custom LASIK usually costs significantly more than traditional LASIK.
How Does LASEK Differ From LASIK?
LASEK (laser epithelial keratomileusis) is a relatively new procedure that is a variation of PRK. Also called epithelial or E-LASIK, LASEK is used mostly for people with corneas that are too thin or too flat for LASIK. In LASEK, the outer layer of the cornea (epithelium) is cut with a trephine-a finer blade than microkeratome. The eye is then covered with an alcohol solution for about 30 seconds to loosen the edges of the epithelium. The epithelial flap is then lifted and an excimer laser is used as it is in LASIK.
Talking to Your Doctor
If your doctor determines that you are a good candidate for LASIK, before scheduling surgery, ask your doctor about:
Possible risks and complications given your particular vision and general health status
The experience of your surgeon--the Council for Refractive Surgery Quality Assurance recommends at least three years of refractive surgery experience
Outcomes of the procedures performed by your surgeon
The percentage of patients who return for enhancements (a second surgery)
Whether your surgeon is using an FDA-approved laser
What is involved in after-surgery care
Who will handle and be responsible for after-surgery care
Be sure to explain to your doctor how you use your eyes, for example, whether you spend hours at the computer, whether you play contact sports where there may a risk of eye injury. Also describe your goals for sight, why you want LASIK, what you expect from this procedure. Remember that LASIK is an elective procedure, and the outcome will affect your vision for the rest of your life.