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During the past decade, LASIK (laser 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. 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, we were often
confronted with that ‘fear factor’ among our patients, Carlson says. But
with the IntraLase, we can more predictably create a corneal flap and
reduce our 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.
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