Intralase cuts enhancement rates by 30% after LASIK

Barbara Boughton
in San Francisco, US

THE Intralase Laser FS can decrease enhancement rates by as much as 30% after LASIK using either the LadarVison 4000 or the VISX Star S3, reported Michael Gordon MD at the annual ASCRS Symposium on Cataract, IOL and Refractive Surgery.
"The Intralase has provided us with more precise flaps and predictability of results, as well as decreasing enhancement rates. It is a much better way to create a flap. You don’t have problems like buttonholes and there’s no corneal abrasion or bleeding. Incomplete and irregular flaps are a thing of the past with the Intralase," he said.

Dr Gordon and colleague Perry Binder MD tested the Intralase on the LadarVision 4000 and the VISX Star S3 platforms in a series of 310 eyes. In their practice, the VISX Star S3 formerly had a 10% enhancement rate and the LadarVision 4000 a 15% enhancement rate. When Dr Binder performed LASIK with Intralase, the enhancement rates with both machines went down by 30%, Dr Gordon said.

Yet when Dr Gordon performed LASIK with the Intralase, enhancement rates on the LADARVision decreased by 30% but increased by 30% with the Visx laser. The technique of each surgeon made the difference. While Dr Gordon lifted the Visx flap and performed ablation immediately after making the flap, Dr Binder waited 10 minutes.
"We learned that with the VISX Star S3 you have to wait 10 minutes to allow hydration changes to occur," Dr Gordon said.

He noted that in addition to creating more precise, uniform flaps, the Intralase flaps have better adhesion two to three months after surgery.
"The stromal bed is also extremely smooth, better than with the best mechanical keratomes. Though there’s no good prospective randomised double blind studies to support this, we’ve seen that surgeries with the Intralase also have decreased tear film abnormalities," he said.

Dr Gordon’s observations about decreased dry eyes and improved corneal sensitivity with the Intralase are important new findings, noted researcher Guy M Kezirian MD, FACS.

"We’ve looked at several data sets about the Intralase and there’s no question that it creates more astigmatically neutral flaps than mechanical keratomes. This is a huge contribution, especially as we move into wavefront," he said.

With mechanical microkeratomes, flaps are often thinner in the centre and thicker in the periphery. Because there is no metal blade with the Intralase, there is no risk of flap thickness irregularities which can result in induced astigmatism.
When produced by mechanical microkeratome, flaps are meniscus-shaped, and crinkles and microstriae can occur in the centre of the flap. The Intralase, in contrast, creates a planar flap - a type of flap that will become much more important in the future, Dr Gordon said.

"There are simply less high order aberrations induced with the Intralase," he added.
Predictable flap thickness is critically important in LASIK, especially in patients with thinner corneas. Dr Gordon’s research backs up claims that the Intralase creates consistent thickness throughout the entire resection.
In a series of 69 eyes, in which he and fellow surgeons aimed for a thickness of 100 microns, the average thickness was 103, with a standard deviation of 10.4, Dr Gordon said.

"The Intralase has the tightest range and smallest standard deviation of any microkeratome on the market. With the Intralase, flaps of any diameter or thickness are possible. The hinge position can also be anywhere you want it to be," he said.
He noted that the Intralase - because it was so precise and versatile - is likely to be quickly accepted as the state-of-the-art for LASIK. He and Dr Binder currently do 95% of all their LASIK cases with the Intralase.

Though procedures with the Intralase are more expensive, patients seem to prefer them to LASIK with mechanical microkeratomes, he said. In early June, he and Binder will start charging the same price for Intralase as other LASIK procedures - $2,200, he said.

"We have raised the fee for traditional LASIK to match the Intralase fee, so there is no reason for the patient not to choose the safer, better procedure. It is more expensive for us, but it’s better for the patient. For us, Intralase is worth the investment because of its characteristics - the superior safety, precision and predictability," Dr Gordon said.

Michael Gordon MD
Gordon/Binder Institute, California, US
Email: MGordon786@aol.com

Guy Kezirian MD, FACS
SurgiVision Consultants Inc, Arizona, US
Email: Guy1000@SurgiVision.biz

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