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Single-use, reusable Moria One microkeratomes compare favorably
Study finds both devices create flaps near intended 160-µm thickness.
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CHICAGO - The LSK-One disposable microkeratome from Moria SA (Antony, France) is just as precise and consistent in creating corneal flaps during laser in situ keratomileusis (LASIK) as is the LSK-One reusable microkeratome, according to a retrospective analysis of 138 eyes in 93 patients.
---The design of the One disposable microkeratome allows for full visibility of the flap during surgery.
"For the past 3 years, we’ve been using the LSK-One metal reusable microkeratome and have been very happy with it," said investigator Jonathan B. Rubenstein, MD, an associate professor of ophthalmology at Rush Medical College here. When Moria introduced a plastic disposable version earlier this year, "I actually liked its performance quite a bit. In fact, the company asked me to keep track of my data and to record such parameters as the thickness of the corneal flap, the dimensions of the flap and the quality of the flap," Dr. Rubenstein said.
To date, Dr. Rubenstein estimates he has performed close to 2,000 LASIK procedures with the Moria reusable microkeratome and roughly 150 cases with the Moria disposable. "The prevailing hypothesis was that, because the single-use device is made out of plastic, it might not render as high a grade quality in reproducibility," he said. "That concern was allayed, however. Our results show that the actual dimension and thickness of the flap are just as predictable as what we achieve with the metal microkeratome." In addition, "the more qualitative assessment of the flaps — how they looked to us, felt and acted — was just as good, if not better, with the reusable unit."
Consistent results
---The microkeratome is ready for resection. Visibility of the sclera through the transparent suction ring indicates proper centration and adequate suction.
For the study, 93 eyes from 67 patients were treated with the reusable Moria LSK-One microkeratome, and 45 eyes from 26 patients were treated with the single-use Moria LSK-One disposable microkeratome. Corneal flap thickness was measured by subtracting the intraoperative corneal bed thickness (after creation of the flap) from the preoperative central corneal thickness (see table).
"The mean flap thickness using the reusable Moria 130-µm head was 159 µm, with a standard deviation of 28 µm, ranging from 103 to 215 µm," Dr. Rubenstein said. "To our surprise, when we calculated the average flap thickness with the plastic disposable microkeratome and a 130-µm head, it was 158 µm, with a standard deviation of 22.4 µm, ranging from 113 to 205." These results "were more consistent than I expected. The average flap thickness was basically identical between the two groups of patients," Dr. Rubenstein said. "It is reassuring to know that you don’t need to change your nomograms, your calculations or your expectations when you use the disposable plastic as opposed to the reusable metal microkeratome."
Subjective assessment of the quality of the corneal flaps and smoothness of the stromal bed were also similar in both groups. "I actually filled out a scaled score card," Dr. Rubenstein said. "When I rated the quality, I really felt that the single-use microkeratome rendered just as good, if not superior, results compared to the reusable microkeratome."
Single-use easier to use
---The two suction rings, -1 and 0, combined with the multi-position stop allow for flaps from 8 to 10 mm in diameter. The stop is placed on the top of the ring for perfect visibility and control at the end of the cut.
Dr. Rubenstein, who is director of refractive surgery at Rush Medical College, also appreciates the fact that "technically, the plastic Moria LSK-One microkeratome is actually quite a bit easier to use than the metal microkeratome, both from the technician's and the surgeon's points of view." The disposable unit "has a little bit of a learning curve because of its slightly different design," he said. "But for someone who has never performed LASIK, I believe it is probably an easier microkeratome to learn how to use for the first time."
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The single-use microkeratome has a smaller footprint; therefore, "it fits inside the eyelids more easily," Dr. Rubenstein said. "It is not as wide, so it fits into small eyes and eyes with a narrower palpebral fissure. These eyes are too narrow to permit a normal suction ring from gaining access to the eye." Furthermore, the plastic device is easier to use because the suction ring portion is made of clear plastic. "The ring provides you with a nice visual clue when you have achieved good suction," Dr. Rubenstein said.
The disposable microkeratome also makes it "very easy to actually slide the microkeratome head into the tracks of the suction ring. It is easier than with the metal microkeratome," Dr. Rubenstein said. And from the technician’s perspective, there is virtually nothing to assemble. "You basically take the unit out of the box and plug in a suction tubing to the suction head," he said. By being essentially pre-assembled, "you increase speed and efficiency, as well as decrease the chance of human error. The blade is already positioned correctly." High-volume surgeons may also see an overall reduction in surgery time.
According to Dr. Rubenstein, Moria is the only major manufacturer of microkeratomes that offers both a reusable and single-use device.
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| Flap thickness | LSK-One 130 Reusable | LSK-One 130 Disposable |
| Mean | 159 | 158 |
| Standard deviation | 28 | 22.4 |
| Range | 103 to 215 | 113 to 205 |
For Your Information:
- Jonathan B. Rubenstein, MD, can be reached at Rush Medical College, 1725 W. Harrison St., Ste. 918, Chicago, IL 60612; (312) 942-2734; fax: (312) 942-2140; e-mail: jrubenst@rush.edu. Dr. Rubenstein does not have a direct financial interest in any product mentioned in this article, nor is he a paid consultant for any company mentioned.
- For product information on Moria One microkeratomes, contact Microtech Inc., 4030 Skyron Drive, Unit G, Doylestown, PA 18901; (800) 441-1314; fax: (215) 230-7670; e-mail: microtech@microtechnic.com.