instrument insider
Easing the Move to a New Laser Platform
A software program helps WaveLight users develop and customize nomograms.
By John Parkinson, Associate Editor

hen contemplating whether or not to integrate a new excimer laser system into a refractive surgery practice, there may be some hesitancy or concern about the transition process. Obvious considerations include learning to master a new platform and developing nomograms, which can take considerable time and effort.

SurgiVision Consultants, Scottsdale, Ariz., has teamed up with WaveLight AG, Erlangen, Germany, to create a shared data system that accelerates the learning curve in developing appropriate treatment nomograms. The SurgiVision DataLink Wavelight Edition software provides surgical planning and outcomes analysis specific to the Allegretto Wave Excimer Laser system, according to the two companies. DataLink is a Web-based derivative of the Refractive Surgery Consultant (RSC) outcomes analysis software developed by Guy Kezirian, M.D., SurgiVision's founder, and Jack Holladay, M.D.

This article will discuss some of the software system's capabilities and provide the viewpoints of one surgeon who recently integrated it into his LASIK practice.

Obtaining an Advantage

David A. Wallace, M.D., medical director at LA Sight, Los Angeles, Calif., was intrigued by the favorable, though anecdotal, reports about the Allegretto Wave laser from other surgeons. If incorporating this laser into his practice would help achieve better or more consistent outcomes, he was, of course, interested. However, he also knew integrating a new laser would come with some challenges.

"Laser-specific and surgeon-specific nomograms are essential if one desires to optimize performance from a particular platform," says Dr. Wallace. "If a laser platform has enough inherent stability, nomogram development can theoretically tighten outcomes scatter due to variables including surgeon technique, environmental, keratome and laser factors. Lasers may have reasonable consistency one to the next, but they don't have absolutely perfect reproducibility — even among lasers of the same brand and model," says
Dr. Wallace. "The challenge is, how do you find out how your laser performs relative to other lasers you may have used in the past?"

When Dr. Wallace first heard about DataLink, he was interested but skeptical about what it could potentially offer.

"If it could help improve patient outcomes and lower my enhancement rate by a small amount, that would certainly be worth knowing," says Dr. Wallace. "And if it could significantly lower enhancement rates below those I had obtained with any other laser I'd used, that would potentially be huge."

Nomogram Development

To facilitate the issues of nomogram development and new laser integration, SurgiVision and WaveLight collaborated to create DataLink. This software system is provided on a complimentary basis exclusively for new Allegretto Wave excimer laser users. DataLink is a Web-based system in which all patient information and outcomes data are entered via a computer interface, and stored on a central server. Individual users can view pooled data from all participants and their own individual data as well. The system provides for secure, encrypted communication between office workstations and DataLink servers. It only allows individual patient information to be viewed by the patient's surgeon. Surgeons who opt to use DataLink simply download and install client software.

Approximately 30 surgeons currently use DataLink in the United States. To obtain initial nomogram recommendations from the pooled database, a surgeon logs on to DataLink, enters patient data including refractive measurements, then selects a specific treatment profile — such as LASIK for myopic astigmatism with a Hansatome XP microkeratome using a 6.5 mm optical zone. DataLink will then process the collected data and provide a suggested treatment to program into the laser for the desired correction.

When enough follow-up data is in the system from a surgeon's own cases, it becomes possible to construct nomograms using this surgeon-specific data rather than pooled data. This transition, which requires a minimum of 2-month postop follow-up data on about 50 eyes, allows further refinement of outcomes.

"It's like an online wizard that helps you collect relevant data, process analyzed data, and refine your nomogram based on your personal experience with your laser," says Dr. Wallace. "It helps streamline and guide the [nomogram] process."

Performance Benefits

The DataLink "pooled data" starting nomograms helped Dr. Wallace decrease his enhancement rate to 5.4% (projected annual). With surgeon-specific nomograms guiding his treatments, his enhancement rate dropped to 3.2%.

Dr. Wallace says that while the differences between the pooled-data nomograms and the surgeon-specific nomograms are subtle, they are clearly significant.

"There are certain circumstances when surgeon-specific nomograms are clearly better," offers Dr. Wallace. "One big issue is 'coupling,' wherein treatment of cylinder power will impact the resultant sphere power. While the type of coupling (positive or negative) may be a characteristic of the laser model, the specific amount of coupling is unique to each machine. Unless you track this stuff compulsively, you are in
the dark."

On rare occasions, lasers can develop errors due to degradation of optical elements (mirrors, lenses) or other performance impairments. Dr. Wallace says another benefit of the Data Link is that with the continuous tracking of results, a mechanical issue can be identified and then appropriately resolved more quickly.

Another area where DataLink has helped Dr. Wallace is with his initial patient consultations. He can explain the probability of patients achieving 20/20 and the predictability of the intended correction with the use of this software.

"It's a way to show performance data to patients as a means of building confidence with our practice," says Dr. Wallace.