Disposable keratome head offers safe myopic treatment

San Diego-The M2 130-µm disposable head (Moria) performed well in a small series of patients who underwent LASIK for the treatment of myopia and myopic astigmatism. The faster surgical path used with this device may be responsible for induction of less higher-order aberration.

The device was evaluated in 100 consecutive patients (100 eyes) who underwent LASIK for myopia and myopic astigmatism. The Allegretto Wave Excimer Laser system (WaveLight Laser Technologie AG) with the 130-µm head was used for all patients. One disposable head was used for each eye at the fastest speed. The follow-up data from the 4-month postoperative visit were presented at the American Society of Cataract and Refractive Surgery annual meeting.

"The mean preoperative sphere in this patient group was –5.25 D (range, –1 to –11.5 D)," reported Gregory J. Pamel, MD, who is an attending surgeon at Manhattan Eye, Ear and Throat Hospital, New York.

The mean flap diameter was 8.5 ± 0.4 mm. The flap thickness was 140 ± 17.5 µm, which was slightly less than in the previous study because data from more patients were presented, according to Dr. Pamel. The mean hinge diameter was 4.5 ± 0.35 mm.

"Wavefront analysis showed that there was a postoperative increase in coma of only 34%; the mean coma was 6% preoperatively and increased to 9% postoperatively," Dr. Pamel reported.

Two complications occurred in this patient group, one free cap in a patient with a keratometry value of less than 40 D, and one thin flap in a patient with a keratometry value of 48 D and pachymetry of 500 µm. In both of these cases, the microkeratome was set to the fastest speed, and Dr. Pamel suggested that altering the speed, which is available with this microkeratome, might affect the results.

Good visualization Dr. Pamel demonstrated his technique with use of this microkeratome, which allows good visualization of the eye.

"There are a number of advantages that are associated with this microkeratome, one of the most important being that there is no technician learning curve when going from a metal to a plastic head," he said.

He added that the plastic head is translucent, making it easy to visualize its placement on the ring. The oscillation speed is 15,000 rotations per minute, which translates to 30,000 cuts per minute.

"The risk of contamination is decreased with the use of a disposable head," he said. "There are no risks of damage to the blade during assembly.

"LASIK performed using the Allegretto Wave Excimer Laser with the M2 130-µm single-use head seems to be safe and very effective in the correction of myopia and myopic astigmatism," Dr. Pamel concluded. "The results in this limited study suggest that this head might induce less higher-order aberrations because of the faster surgical path."