The Eyes Have It

Methods for correcting vision have evolved dramatically in the past 10 years, with the Doheny Eye Institute leading the new view of eye surgery.

By Monika Guttman

Ed Bixler and his wife Diane like to jump on his Harley-Davidson motorcycle and cruise up the coast, enjoying the scenic panoramas as the wind whips past. “We both gave up our bikes when we had the kids,” explains the 63-year-old investment banker. “Once we became empty-nesters, we decided to take it up again.”

There is a lot that Bixler appreciates about riding his bike this time around—at the top of the list is the freedom from glasses. Bixler had always wanted to ditch the eyewear that would get distorted from dust and debris or bump into the face shield of his helmet when he was riding his bike. He had checked out having the procedure known as LASIK (laser-assisted in situ keratomileusis, a form of refractive laser eye surgery for correcting vision) but had been told that his astigmatism made a LASIK procedure impractical.

Then, last winter the Bixlers were at the Doheny Eye Institute at USC for an appointment. “There was this woman in the elevator who was so happy; she had just completed her last appointment for her LASIK. Like me, she had been told before it wasn’t possible for her eyes. She was so excited,” Bixler recalls. He got the name of the woman’s ophthalmologist at the Doheny Refractive Surgery Center: David Huang, M.D., Ph.D., also director of the center. In February Bixler had LASIK surgery, and today he bikes without glasses.

Eye tools

LASIK has come a long way, baby, since the first procedure was performed in the United States in 1991. More than three million people are living without glasses, thanks to the corrective surgery. Constant technological developments, new lenses and a host of new techniques provide ophthalmologists with an arsenal of tools that make surgery possible for some of the most difficult vision problems. “People with glasses or contacts generally say they’d do anything to get rid of them,” Huang says. “Some people refer to their poor eyesight as a handicap.”

Refractive surgery is any type of eye surgery, including LASIK, which affects the way that light enters the eye. “Refractive describes any condition that causes light not to be focused in the eye. It includes what a lot of people know as nearsightedness or farsightedness or astigmatism, because those are the terms used by doctors who prescribe glasses,” Huang says.

LASIK is a procedure that uses an excimer laser to permanently change the shape of the cornea, the clear covering on the front of the eye. A simplified explanation of a traditional LASIK procedure begins with the eye surgeon using a knife called a microkeratome to cut a hinged flap in the cornea. The flap is folded back to reveal the stroma, the middle section of the cornea. A computer-controlled laser vaporizes a portion of the stroma to reshape the cornea and the flap is replaced. LASIK today, says Huang, contains many different variations on that technique.

He points to the example of “wavefront-guided” LASIK surgery, which is allowing vision correction for patients who might not have been good candidates before because they were too nearsighted or farsighted. “The advanced laser treatment patterns reduce ‘higher order aberrations’—more complex patterns of optical defects than the usual nearsightedness or astigmatism,” he says. “Wavefront-guided LASIK surgery can improve the quality of vision and reduce the side effects associated with conventional LASIK, such as blurriness or a halo or starburst when looking at street lights at night. This makes a big difference for people with high degrees of nearsightedness or farsightedness.”

An eye surgeon using wavefront technology begins by shining a beam of light into the patient’s eye “which measures reflection over several hundred locations in the eye. This gives a map that is much more precise and much more complete than was available with other technology,” Huang says. The map is used for the LASIK procedure and reduces side effects because of the intensified precision.

According to the Food and Drug Administration, studies comparing wavefront-guided LASIK to conventional LASIK showed that a slightly larger percentage of people treated with wavefront LASIK achieved 20/20 vision without glasses or contact lenses compared to people treated with conventional LASIK.

See free

Huang performs a variety of procedures, including LASIK and PRK with the CustomVue technology, Intacs intracorneal implants and natural lens replacement. He says he is excited to break new ground when it comes to eye surgery and eye imaging. His best-known invention in eye imaging is Optical Coherence Tomography (OCT).

OCT is an imaging technique that uses light waves to create an image of very small portions of the eye—usually the retina—much like sound waves are used in an ultrasound to create an image. By measuring how the light waves are reflected in a sequence of several hundred scans across the retina, OCT can output a map of retinal thickness. OCT is now a common technique for imaging and measuring internal eye structures with microscopic precision.

Huang also has been working with Verisyse phakic intraocular lens implants, an ultra-small lens that is inserted behind the cornea inside the eye. Used in Europe for almost two decades to correct severe myopia (nearsightedness), phakic implants were only approved by the Food and Drug Administration in 2005.

Last year Huang began implanting the phakic lenses in patients whose vision problems were too severe to be corrected with traditional LASIK surgery. The beauty of this procedure is that if there is enough room in the eye to accommodate the lens without touching the natural lens or the cornea, this tiny plastic implant can restore vision so people who wore thick glasses can be completely free of glasses and contacts.

“Most people who are highly nearsighted have a longer eye, so generally they have a little more room in the eye and are good candidates for this procedure,” Huang says. “These are people with Coke-bottle-bottom glasses, and now we have options even for them.”

Huang also performs Intacs implants for patients with thin corneas or distorted corneas. These intracorneal rings are tiny half-moon shaped devices inserted between the layers of the corneal stroma, one on each side of the pupil. By setting the rings in the cornea, the cornea is essentially flattened and that changes the refraction of light passing through the cornea. “These also are for people who are told not to have LASIK because of vision distortion. We can reduce the distortion, lower the prescriptions, and possibly restore vision to a level that allows a person to resume driving,” he says.

“The new implants will correct a greater range of vision issues, not just nearsighted but also farsighted and astigmatism.” Huang believes this procedure will become readily available within the next five years.

Huang is sure more implants will become available in the future, allowing even more people to become candidates for vision correction surgery. “Right now the drawback is the size of the lenses—they require a large incision. The lenses of the future will be implants that require only small incisions or can be placed behind the iris.”

As much as he appreciates the possibilities and potential of the new technologies, what Huang really likes is the end result of vision correction surgery.

“After this kind of surgery, patients say it changed their lives,” he says. “People perceive their eyesight limitations as a handicap they’ve been trying to get rid of their whole lives. It’s not as obvious as a wheelchair or crutches, but wearing thick glasses can make a person self-conscious and uncomfortable. There’s nothing like watching how improved vision changes someone’s outlook.” No pun intended, he laughs.