Published: Jan. 2, 2008
Updated: July 10, 2009
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During the past decade, LASIK (Laser-Assisted In Situ Keratomileusis) surgery has freed more than eight million Americans from daily dependence on glasses and contacts, and the number of people who choose to undergo the procedure increases every year.
LASIK alters the structure of the cornea -- the transparent part of the eye that helps it to focus -- by selectively removing tissue from the stroma, its middle layer. But first the eye surgeon cuts a corneal flap and folds it back to permit laser access to the underlying tissue. The flap is created with a tiny surgical blade called a microkeratome. And, simply put, patients are afraid of the blade -- it has traditionally been the most anxiety-provoking part of the procedure.
Fortunately, a bladeless LASIK procedure is now available at the Duke Center for Vision Correction and it has become the overwhelming choice of patients. Replacing the blade is the IntraLase, a laser that emits infrared light pulses of extremely short duration -- measured in femtoseconds (a millionth of a billionth of a second).
"This computer-guided laser creates a predictable flap with pinpoint accuracy and with less damage to surrounding tissue," says Alan Carlson, MD, professor of ophthalmology and chief of the Cornea and Refractive Surgery Service at Duke. The super-fast laser (delivering 60,000 pulses per second) gives the surgeon more control during the procedure as well as the ability to establish the precise dimensions and thickness of the corneal flap -- factors critical to a successful LASIK outcome. In addition, it takes only 20 seconds to create the flap, and the surgeon can see exactly what is occurring during the procedure.
"Even though the microkeratome is an accurate instrument, surgeons were often confronted with that ‘fear factor’ among patients," Carlson says. "But with the IntraLase, they can more predictably create a corneal flap and reduce patients’ anxiety levels at the same time."
Since the IntraLase arrived in the spring, only one of several hundred patients undergoing LASIK at Duke opted for the microkeratome step instead of IntraLase. "I’m pleasantly surprised because I thought patients would be hesitant about the new technique," says Terry Kim, MD, associate professor of ophthalmology. But patients have embraced this new technology and have associated the laser with precision, safety, greater effectiveness, and less invasiveness.
The all-laser LASIK procedure has few drawbacks, Kim says. Patients treated with the earlier generations of IntraLase sometimes experienced more inflammation and light sensitivity after LASIK, although it was generally resolved with additional medications. Duke’s IntraLase is the latest, fourth-generation model, which few other centers have. The all-laser procedure is more expensive, but patients agree that the added level of safety, assurance and predictably better vision is worth the investment, Kim adds.
The Eye Center corneal specialists, including Natalie Afshari, MD, also have plans to use the IntraLase for select patients needing a corneal transplant, Carlson notes. In fact, the laser’s versatility is one of the reasons the Eye Center decided to invest in the technology. Currently, patients with scarring on the front of the cornea or disease within it receive a full-thickness, donated cornea from an eye bank. The IntraLase has renewed interest in lamellar procedures, which involve removing and replacing only those corneal layers that are diseased or damaged. The ability to remove tissue selectively in a precise and programmable way means that we can use fewer stitches and shorten the healing process after the transplant, Carlson says.
Carlson and Kim are pleased with the outcomes using IntraLase and the enthusiasm of their patients. "All I can say is, patients love the laser," Kim says.