Refractive Insights

The Zyoptix XP microkeratome is the latest-generation device for flap creation, and is the successor to Hansatome^® microkeratome, which has been used in over 7 million LASIK procedures worldwide.

A growing body of evidence presented in peer-reviewed scientific sessions at ASCRS 2006 confirms that there is no safer or more precise method of flap creation available today. Here is a roundup:

	Two independent studies compared LASIK with the Hansatome microkeratome vs. LASIK with the IntraLase device, and reported no intraoperative complications in either group. (Dr. Elizabeth Davis, Dr. Edward Manche)
	Latest method of measuring flap thickness, non-contact optical coherence pachymetry, demonstrated equivalent flap thickness precision in two separate studies comparing the XP and IntraLase. (Dr. HM Lee, Prof. Thomas Neuhann). Additionally, in one study there were no differences in high or low contrast, best- corrected visual acuities demonstrated. (Dr. Lee)
	Additional studies of the Zyoptix XP confirmed a standard deviation of flap thickness of 14 to 16.5 microns.(Dr. Robert K. Maloney, Dr. Michael Mockovak)

Researchers presenting at ARVO find results for LASIK with the Hansatome to be equivalent to IntraLase LASIK. IntraLase flaps thicker than intended, 142-microns vs. 120-micron target; standard deviation reportedly 16 microns.

Morphology study of IntraLase laser bubbles within the stroma shows tissue bridges remain intact, requiring manual dissection to tear open the flap.

Cleveland Clinic Study reports rainbow starbursts in 19% of one cohort of IntraLase cases, linked to residual bubble pattern on posterior flap.

Mayo Clinic researchers identify corneal backscatter in IntraLase cases.

TLS Update: The incidence of this new glare phenomenon characterized by severe photophobia, so called transient light sensitivity, reportedly ranges from 1% to as high as 2.5%.

Older and newer IntraLase devices compared in Cleveland Clinic Study; "photophobia/TLS" reportedly reduced from 21.3% to 11.7%.

Buttonholes and incomplete flaps reported in a study of more than 3,000 IntraLase cases. See how these flap complication rates with IntraLase compare to peer-reviewed, published studies of more than 62,000 Hansatome microkeratome cases.

LASIK with the Zyoptix XP microkeratome is up to 3 to 4 minutes FASTER than LASIK performed with the latest IntraLase device, according to an IntraLase investigator.

Model I IntraLase laser identified as source of rainbow glare, though incidence persists with newer version.

See a comparison of flap thickness variability amongst mechanical microkeratomes in a review of 5,811 cases.

Booth Schedule

For the latest epi LASIK results presented at the AAO in Las Vegas:

JJ Bausch Innovators Lecture Series
Saturday, November 11, 2006 — 3 pm
Booth #831

Epi LASIK Results with the Zyoptix XP Microkeratome
Erik Mertens, MD
Antwerp, Belgium

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1.	Prospective Randomized Eye-to-Eye Comparison Between a Femtosecond Laser and the Hansatome in Myopic LASIK Using the CustomVue Laser, Edward Manche, MD. Presented at the ASCRS, March 20, 2006.
2.	Comparative Study of LASIK Flap Creation with 30FS Laser Versus Hansatome Microkeratome, Elizabeth A. Davis, MD, Richard L. Lindstrom, MD. Presented at the ASCRS, March 21, 2006.

Optical Coherence Versus Ultrasound Pachymetry Measurements in Refractive Surgery, Hung Ming Lee, MD. Presented at the ASCRS, March 19, 2006.

Online Pachymetry and Online Rotational Eye Tracking for LASIK with the New Zyoptix Excimer Laser, Prof. Thomas Neuhann. Presented at the ASCRS, March 20, 2006.

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Optical Coherence Versus Ultrasound Pachymetry Measurements in Refractive Surgery, Hung Ming Lee, MD. Presented at the ASCRS, March 19, 2006.

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1.	Flap Thickness and Variability with the XP Microkeratome, Robert K. Maloney, MD. Presented at the ASCRS, March 20, 2006, San Francisco, CA.
2.	Outcomes After 322 Zyoptix XP Microkeratome Keratotomies in Conjunction with LASIK, Michael Mockovak, MD. Presented at the ASCRS, March 21, 2006, San Francisco, CA.

In a randomized, prospective contralateral eye study comparing LASIK results with the Hansatome microkeratome to those with the IntraLase device, Mayo Clinic researchers found:

No differences in high contrast corrected and uncorrected visual acuity
No differences in contrast sensitivity
No differences in corneal sensitivity

Seventy-five percent (75%) of patients either preferred vision in their Hansatome-treated eye or expressed no preference between eyes, while 25% preferred vision in their IntraLase eye.

Patel SV, McLaren JW, Maguire LJ, et al. A randomized-controlled study of bladeless and microkeratome LASIK. Presented at the ARVO, Ft. Lauderdale, FL, May 3, 2006.

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J. Schultz. Researchers analyze femtosecond laser bubble morphology — Ocular Surgery News, U.S. EDITION, March 1, 2006.

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Residual micro-irregularities on the back surface of IntraLase flaps, referred to as micro-craters, scatter light.
The resulting spectral pattern most closely represented 4 to 12 radiating bands of rainbow-colored light.
In 63% of patients who reported this phenomenon, symptoms persisted beyond 9 months postoperatively.

Krueger R, MD, Thornton I, MD, Van den Berg T, PhD. Rainbow glare as an optical side effect of IntraLASIK. Presented at the ASCRS, March 2006, San Francisco, CA.

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In a randomized, prospective contralateral eye study comparing LASIK results with the Hansatome microkeratome to those with the IntraLase device, Mayo Clinic researchers found corneal backscatter was higher after bladeless LASIK than after LASIK with the microkeratome at 1-month postop (p=0.003), 3-months postop (p=0.014), and 6-months postop (p=0.045).

Seventy-five percent (75%) of patients either preferred vision in their Hansatome-treated eye or expressed no preference between eyes, while 25% preferred vision in their IntraLase eye.

Patel SV, McLaren JW, Maguire LJ, et al. A randomized-controlled study of bladeless and microkeratome LASIK. Presented at the ARVO, Ft. Lauderdale, FL, May 3, 2006.

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While the incidence of this novel glare phenomenon associated with IntraLase use appears to be related to the energy level of the laser used to create the flap, the incidence remained at 1% in at least one group of more than 2,000 patients despite a lowering of the energy level.¹

1.	Stonecipher KG, Dishler JG, Ignacio TS, Binder PS. Transient light sensitivity after femtosecond laser flap creation: clinical findings and management. Cataract Refract Surg. 2006,32(1):91-4.

1.	Krueger R, MD, Thornton I, MD, Van den Berg T, PhD. Rainbow glare as an optical side effect of IntraLASIK. Presented at the ASCRS, March 2006, San Francisco, CA.
2.	The spectral pattern associated most closely to the patients� experience represented 4 to 12 radiating bands of rainbow-colored light.

1.	Jacobs JM, Taravella MJ. Incidence of intraoperative flap complications in laser in situ keratomileusis. J Cataract Refract Surg. 2002;28(1):23-8.
2.	Nakano K, Nakano E, Oliveira M, et. al. Intraoperative microkeratome complications in 47,094 laser in situ keratomileusis surgery. J Refract Surg. 2004;20(suppl):S723-6.
3.	Complications and Management of Femtosecond IntraLase-Assisted Procedures, Methiye �nder, MD, Efekan Coskunseven, MD, and Kazim Devranoglu, MD. Presented at the AAO, October 2005.

Elizabeth A. Davis, MD: The Time is Now to Switch to All-Laser LASIK. Ophthalmology Management. 2006:69-70.

Optical upgrade to the Model I IntraLase laser, which provides a focusing lens with a higher numerical aperture, reportedly reduced but did not eliminate the incidence of rainbow glare from 19.3% to 2.5%. This upgrade was unrelated to 30 kHz or 60 kHz upgrades, which increase the speed of the laser.

Krueger R, MD: Microkeratomes. Presented at the ASCRS Summer Refractive Congress, Seattle, WA, August, 2005.

Krueger R, MD, Thornton I, MD, Van den Berg T, PhD. Rainbow glare as an optical side effect of IntraLASIK. Presented at the ASCRS, March 2006, San Francisco, CA.

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