What is LASIK?
LASIK is a surgical procedure intended to reduce a person’s dependency on glasses or contact lenses. LASIK stands for Laser-Assisted In Situ Keratomileusis and is a procedure that permanently changes the shape of the cornea, the clear covering of the front of the eye, using an excimer laser. A knife, called a microkeratome, is used to cut a flap in the cornea. A hinge is left at one end of this flap. The flap is folded back revealing the stroma, the middlesection of the cornea. Pulses from a computer-controlled laser vaporize a portion of the stroma and the flap is replaced. There are other techniques and many new terms related to LASIK that you may hear about such as Custom LASIK (Wavefront) or bladeless LASIK
After applying anesthetizing drops, the surgeon marks the eye to indicate where the flap will be cut and then replaced.
A suction ring holds the eye still and pressurizes it so it is firm enough to cut.
The microkeratome slices a tiny flap in the cornea.
The flap is moved out of the way, but it is still attached.
The laser removes tissue to reshape the cornea. The flap is replaced on the eye.
Custom (Wavefromt) LASIK
Custom LASIK surgery, also known as wavefront LASIK or wavefront-guided LASIK, uses 3-dimensional measurements of how your eye processes images to guide the laser in re-shaping the front part of the eye (cornea). With a wavefront measurement system, some extremely precise, individualized vision correction outcomes may be achieved that would be impossible with traditional LASIK surgery, contact lenses, or eyeglasses.
Custom LASIK’s advantage lies in the area of quality of vision:
- Greater chance of achieving 20/20 vision
- Greater chance of achieving better than 20/20 vision
- Reduced chance of losing best-corrected vision
- Reduced chance of losing visual quality or contrast sensitivity
- Reduced chance of night-vision disturbances and glare
IntraLase: Creating a LASIK Flap with Precision
A recently developed technology called IntraLase appears to enhance the safety of LASIK vision correction by using laser energy instead of a microkeratome, a cutting tool with a metal blade used in traditional LASIK procedures.
With IntraLase, a special laser is used instead of a blade to create the flap. Then the usual excimer laser does the ablation. So in the IntraLase procedure, two different lasers are used, which is why it is sometimes promoted as “bladeless” or “all-laser” LASIK. As in typical LASIK, the flap then is replaced to serve as a type of natural “bandage” for healing.
LASIK Risks and Complications
Complications generally were more common in the early years of LASIK, when studies in the late 1990s indicated that up to 5% of people undergoing the procedure experienced some type of problem.
Experienced LASIK surgeons now report in trade journals that serious complication rates can be held well below 1%, but only if surgical candidates are selected very carefully. You may be eliminated as a LASIK candidate, for example, if you have certain conditions such as pregnancy or diabetes that affect how well your eye heals.
Any health condition you have that might hamper your ability to heal should be mentioned and discussed in detail with your eye surgeon. Large pupil sizes also might be risk factors for LASIK complications, because pupils in dark conditions could expand beyond the area of the eye that was treated.
While LASIK outcomes are overwhelmingly favorable, remember that there is still that fraction of less than 1% of people who do experience sometimes serious and ongoing vision problems following LASIK. These are likely the people who operate anti-LASIK web sites filled with chilling warnings regarding dangers of the procedure, with nothing positive ever said. You should rationally consider what unhappy LASIK patients have to say in light of your own needs and the fact that it is absolutely true that no surgical procedure is ever risk-free.
A very small number of LASIK patients with excellent vision based on eye chart testing still can have bothersome side effects. For example, it is rare but possible that a patient may see 20/20 or better with uncorrected vision while at the same time having symptoms such as double vision (diplopia), unresolved dry eye, or difficulty seeing at night because of glare or halos around lights.
Finding a Good LASIK Surgeon
Advertisements, academic medical centers and the American College of Surgeons. Many refractive surgery centers are advertising in newspapers, on the radio, and on TV. Some ads are more informative than others; and some tout extremely good pricing. But while they can be a starting point, an ad or a procedure price should not be your only criterion in choosing a doctor.
Referrals. Ask for a referral from your regular eyecare practitioner, whether an optometrist or an ophthalmologist. Tell him or her that you want the LASIK surgeon in your area with the best reputation in the profession.
Other resources. Visit the American Academy of Ophthalmology’s website at www.aao.org, where you can use the “Find an Eye M.D.” feature. Be sure to specify “refractive surgery” under “specialty.”
Call refractive surgery centers in your area; you’ll find them in the Yellow Pages. Most have websites that explain their specialties and doctor credentialing. Some even let you search for particular surgeons on their sites.
Glossary
Ablate: in surgery, is to remove.
Acuity: clearness, or sharpness of vision.
Astigmatism: a distortion of the image on the retina caused by irregularities in the cornea or lens.
Diopter: the measurement of refractive error. A negative diopter value signifies an eye with myopia and positive diopter value signifies an eye with hyperopia.
Excimer laser: an ultraviolet laser used in refractive surgery to remove corneal tissue.
Flap & Zap: a slang term for LASIK.
Glare: scatter from bright light that decreases vision.
Halos: are rings around lights due to optical imperfections in or in front of the eye.
In Situ: a Latin term meaning “in place” or not removed.
Keratectomy: the surgical removal of corneal tissue.
Keratotomy: a surgical incision (cut) of the cornea.
Keratitis: inflammation of the cornea.
Laser: the acronym for light amplification by stimulated emission of radiation. A laser is an instrument that produces a powerful beam of light that can vaporize tissue.
LASIK: the acronym for laser assisted in situ keratomileusis which refers to creating a flap in the cornea with a microkeratome and using a laser to reshape the underlying cornea.
Lens: a part of the eye that provides some focusing power. The lens is able to change shape allowing the eye to focus at different distances.
Microkeratome: a surgical device that is affixed to the eye by use of a vacuum ring. When secured, a very sharp blade cuts a layer of the cornea at a predetermined depth.
PRK: the acronym for photorefractive keratectomy which is a procedure involving the removal of the surface layer of the cornea (epithelium) by gentle scraping and use of a computer-controlled excimer laser to reshape the stroma.
Radial Keratotomy: commonly referred to as RK; a surgical procedure designed to correct myopia (nearsightedness) by flattening the cornea using radial cuts.
Retina: a layer of fine sensory tissue that lines the inside wall of the eye. The retina acts like the film in a camera to capture images, transforms the images into electrical signals, and sends the signals to the brain.
Wavefront: a measure of the total refractive errors of the eye, including nearsightedness, farsightedness, astigmatism, and other refractive errors that cannot be corrected with glasses or contacts.
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