IntraLase Laser Flap Achieved a 30% Reduction in Standard Deviation Versus the B&L XP Bladed Microkeratome

IRVINE, Calif., Oct. 13 /PRNewswire-FirstCall/ -- IntraLase Corp. (Nasdaq: ILSE) today commented on recent claims made in a head-to-head study concerning the comparative outcomes of Bausch & Lomb's bladed microkeratome device versus IntraLase's Femtosecond (FS) laser instrument. A Bausch & Lomb sponsored study performed by Dr. Hung Ming Lee (Tan Tock Seng Hospital, Singapore) demonstrates superior precision for the IntraLase FS laser and equivalent short term visual results, even though the newest IntraLase model was not used. Moreover, the setting selected for the IntraLase flap thickness was unusually high. In fact after this study Dr. Lee now uses the IntraLase FS laser in the majority of his LASIK cases.

The study, which is being presented at a Bausch & Lomb sponsored symposium, is not part of the peer-reviewed annual meeting of the American Academy of Ophthalmology being held this week in Chicago. Data released by B&L compared standard refractive results and contrast sensitivity at one day, one week, and one month post-operatively. Patients participating in the study had flaps created in one eye by the Zyoptix XP and in the fellow eye by the IntraLase FS laser operating at 15 kiloHertz (the older model). Intraoperative measurements revealed the achieved flap thickness averaged 118 microns in the Zyoptix eye, but was 30% thicker (156 microns) in the IntraLase eye.

Unlike a mechanical microkeratome, the IntraLase FS is computer controlled and can be set to achieve a wide range of flap thickness. In several peer reviewed clinical studies (and in general clinical practice) a much thinner flap thickness is programmed into the laser and achieved, usually between 100 and 120 microns. Thicker flaps have been reported to result in slower visual recoveries, more significant biomechanical effects and optical aberrations. Two separate prospective, contralateral eye studies done in the United States at the US Navy Medical Center and at Stanford University comparing the IntraLase FS laser and mechanical microkeratomes are being presented at the AAO Refractive Subspecialty Meeting, and the main AAO Annual Meeting, both peer reviewed meetings. In these two studies, Dr. Edward Manche (Stanford University) and Drs. Steven Schallhorn and David Tanzer (U.S. Naval Medical Center) achieved flaps of 110 and 100 microns, respectively. In both studies, statistically significant improvements in contrast acuity and uncorrected vision were seen with the IntraLase FS.

More Good News for IntraLase

Despite the use of a flap thickness setting that was 50% greater than a typical IntraLase setting, and over 30% thicker than the thickness selected for the Zyoptix XP, the IntraLase flap achieved a 30% reduction in standard deviation versus the mechanical device. In the IntraLase eyes, a standard deviation of 9.5% was achieved, while for the Zyoptix XP the standard deviation was 12.3% of the average flap thickness. If equivalent flap thickness had been used in the study, a standard deviation of 11 microns would have been expected with the IntraLase, versus 15 microns with the Zyoptix XP. This 11 micron extrapolation is consistent with several previous peer-reviewed publications of the IntraLase FS. (Data on file)

IntraLase FS Laser Creates Planar Flap

Creation of a planar flap has been suggested as one of the primary reasons for superior visual results with the IntraLase FS. While a mechanical microkeratome produces an irregular flap that is thinner centrally and thicker peripherally (meniscus shaped), the IntraLase FS creates a uniform thickness flap. Therefore, even a uniformly thicker IntraLase flap may better preserve the integrity of the peripheral cornea and introduce fewer biomechanical effects and optical aberrations than a centrally thinner mechanical one. The equivalent visual results between IntraLase planar 156 micron flaps and Zyoptix XP 118 meniscus-shaped flaps are consistent with this hypothesis.

Core Computer Technology Continues to Evolve

The study reports a two fold increase in suction time. With the current model IntraLase FS30 the suction times would be roughly equivalent (56 sec for FS30 vs. 44 sec for XP). Moreover the highest volume LASIK surgeons in the world use IntraLase as their standard of care dispelling any myths of prolonged surgery time. And the core computer technology used in the IntraLase platform continues to increase in speed.

The Bottom Line

"After using both the new Bausch & Lomb XP and the IntraLase FS30, I am convinced the 30 kHz IntraLase provides both better control of flap thickness and flap architecture and drives better visual outcomes. Our patients definitely prefer the laser over the blade. This is why we use IntraLase on essentially all of our patients," states Jon Dishler MD of the Laser Institute of the Rockies.

IntraLase congratulates Dr. Lee on his clinical study with Bausch & Lomb. We are especially pleased to note that, after his comparison study, he uses the IntraLase FS laser on the vast majority of his LASIK cases.