Vision Problems

Corrective Surgeries, Part 2
by Food and Drug Administration (FDA)

(Page 4 of 5)

The advantages of LASIK include a quicker visual rehabilitation, reduced pain and discomfort, and the surgeon's ability to treat higher levels of refractive error without the limitations associated with PRK.

Three years after LASIK, Ricketts says, "My vision couldn't be better. I'm happy I had the surgery," she says, "but I didn't spend my life wanting to have it done." Although she still wears glasses to correct presbyopia, Ricketts is currently considering a relatively new procedure that would reduce her need for reading glasses.

Doctors say that one of the keys to a successful LASIK procedure is the measurement that an ophthalmologist takes to determine refractive error. Small imperfections in the eye may cause some light to travel through the eye at different angles, making light strike the retina in different places. Collectively, these imperfections are called optical aberrations.

Traditional laser technology allows for correction of the refractive errors myopia, hyperopia, and astigmatism, also known as "lower order" aberrations. A new excimer laser procedure, called wavefront-guided LASIK, treats lower order and "higher order" aberrations, which are subtle focusing imperfections in an eye's optical system that can result in less-than-optimal clarity.

Wavefront, or custom LASIK, uses a measuring device to create a "map" of how a person's eye focuses light to precisely assess the unique irregularities and variations of the eye. These variations, experts claim, can be as unique as a person's fingerprints.

The FDA approved the excimer laser for use in wavefront-guided LASIK in 2003. Ricketts's 28-year-old daughter, Lindsey Hocker, of Frederick, Md., underwent the relatively new custom corneal surgery less than one year after it first became available.

"Regular LASIK came highly recommended to me by several people, and seeing the success that Mom had with LASIK convinced me to do it," Hocker says. "But because of the problems I had, I decided to go with my doctor's recommendation for the custom cornea."

The wavefront map is very detailed: Instead of simply creating a general description of the eye's focusing power, for example, nearsightedness, farsightedness, or astigmatism, it records every subtle distortion in the pathway of light moving through the eye.

"Immediately after the surgery," Hocker says, "I could see the clock on the wall for the first time since the fourth grade." The only side effect she has experienced in two years was dry eyes after surgery.

Although it's natural for people to want to hear the success stories of others who have undergone a type of surgery, the FDA recommends that people avoid being influenced by others encouraging them to have such procedures. Not everyone is a candidate for every procedure.

Laser Epithelial Keratomileusis, or LASEK, is a variation of LASIK, and corrects myopia, hyperopia, and astigmatism. The epithelium, or outer surface of the cornea, is loosened with alcohol, not with the microkeratome used in LASIK. It is then peeled back to expose the cornea. The same excimer laser used in LASIK is applied to the cornea, but only to the surface. The epithelium is placed back into position, and a bandage contact lens is placed on the eye to promote healing. Like LASIK, the recovery time is rapid. Discomfort is somewhat increased, compared with LASIK.

LASEK is similar to PRK. The difference is that with LASEK, the epithelium is replaced after surgery. In PRK, the epithelium is discarded. Both PRK and LASEK are similar to LASIK in that they use the excimer laser to shape the cornea.

While the FDA regulates excimer lasers, the agency doesn't have the authority to regulate a doctor's practice of medicine or the off-label use of medical products. Therefore, the FDA does not tell doctors what to do when running their businesses or what they can or cannot tell their patients. Consequently, people considering laser surgery should ask questions and fully understand any procedure they might be considering.

The idea of a person walking into a doctor's office and an hour later walking out with perfect vision is a very attractive one, but the reality is that these are surgical procedures with potential complications, and perfect results are not guaranteed, experts say. Everette Beers, Ph.D., chief of the FDA's Diagnostic and Surgical Devices Branch, reminds people that refractive surgeries are elective procedures, some of which can't be undone.

"People need to remember that you can change glasses or contacts, but not implants or surgery," he says. Be sure to consult with a refractive surgeon to determine your eligibility for surgery. Beers also warns that surgical procedures are not without some risk, and that "the long-term effects of many procedures are still unknown."

According to the American Academy of Ophthalmology (AAO), more than 90 percent of people who have refractive surgery for myopia and astigmatism end up with 20/40 vision or better without glasses, a correction sufficient enough to allow them to drive legally without glasses. Sixty percent to 70 percent of patients achieve 20/20 vision or better.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.