Until recently, excimer lasers have been programmed with standard refractive data to reshape the cornea. But a new technology, called wavefront analysis, is able to measure optical aberrations beyond what can be neutralized by subjective refraction.

Laser manufacturers are working hard to incorporate this technology into laser systems they anticipate will be capable of highly customized treatments that can make corrections for all optical aberrations. Some are hoping that within 5 to 10 years, wavefront-guided lasers will enable people to achieve super vision of 20/10 or 20/15.

Canadian surgeons are promoting wavefront-guided LASIK to US consumers. And the FDA’s recent approval of one laser manufacturer’s application to sell this equipment in the United States has built some excitement in the media. The result is that many prospective patients are becoming interested in this new technology. However, we advise caution.

We have used wavefront analysis for several years and are very interested in its application to LASIK. However, we have misgivings about wavefront-guided treatment at this early stage. All our surgeons currently advise against it. The following explanations are provided for your consideration.

The difference between standard and custom LASIK might be compared to buying shoes. A standard factory-made shoe is selected by size and width, but a custom-made shoe relies on numerous measurements to create a perfect fit for each foot.

The location and depth of standard LASIK ablation is based on sphere, cylinder and axis, the measurements so successfully used to create corrective lenses. If customized treatment is desired, there are 2 options for more detailed measurements:

• Wavefront analysis—provides 4 to 100 numbers that identify aberrations found throughout the entire optical system.
• Corneal topography—provides a topographical map of surface aberrations based on 4000 to 6000 points of measurement.

If abnormalities that cause focusing problems are known to be on the surface of the cornea, we believe corneal topography provides better guidance for custom LASIK. However, when aberrations arise from a composite of the optical media, wavefront analysis is a more accurate measurement to guide customized treatment.

Customized treatment at Pacific Cataract and Laser Institute has been directed to patients with corneal surface problems. So our development and FDA research study started with topography-guided custom LASIK.

Wavefront measurements are interesting and useful, but we are not convinced that such highly customized treatment should be used to correct every focusing abnormality. Vision could end up worse than if treated by standard LASIK. Our concerns are based on the following risk factors:

1. Heightened expectations for 20/10 or 20/15 super vision may lead to frustration when patients do not achieve this goal.
2. Wavefront-guided LASIK may reshape the cornea to compensate for aberrations that arise from the lens. But with time, most patients will develop normal lenticular changes and

3. Wavefront-guided treatment is much more complex than standard LASIK, so there is more to go wrong. From our experience we have 4 areas of concern:
   • Wavefront measurements are not consistently accurate. Errors may be present that could misguide the laser treatment.
   • It is possible for some wavefront measurement data to be lost in the translation to the laser treatment plan.
   • All computerized eye trackers we have observed have accuracy problems the manufacturers do not seem to recognize. Critical eye centration can be slightly off during treatment. Decentered treatment is never good, but slightly decentered custom treatment can create complex aberrations.
   • With the cornea being 70% water, highly customized treatment is like trying to precisely sculpt Jell-O. Even when everything is done perfectly, creating the LASIK flap and the normal effects of corneal stretching, molding or healing may negate some of the precision of the planned treatment.
4. Customized wavefront-guided LASIK may treat temporary irregularities—which would change in time if left alone. So considering the shoe analogy, if measurements for custom-made footwear are taken when part of the foot is swollen, the customized shoe will no longer fit when the foot heals.
5. The assumption that it is best to reduce or eliminate all abnormalities detected by wavefront is currently in question. Studies so far have failed to show that people with the best vision have less wavefront abnormalities.

Computerized tracking systems focus and lock on to the edges of the pupil—which lies 4 mm beneath the treatment surface. As the eye makes tiny movements these sophisticated trackers keep the laser beam aligned to the middle of the pupil. The problem is that eye movements detected on the pupil plane are exaggerated on the corneal surface plane. Small eye movements can throw the cornea treatment zone off target—even when the pupil is perfectly tracked. When this occurs, a higher degree of distortion can be created than the minor details the custom LASIK was attempting to treat.

For this reason, Pacific Cataract and Laser Institute’s surgeons have always immobilized patients’ eyes throughout the laser ablation. A fixation system we have developed enables our surgeons to hold the eye on target with very little possibility for error.

At this time, there are many reasons to be cautious. Patients have little to gain and a lot to lose by jumping into the relatively unproven treatment of custom wavefront-guided LASIK. It may be months or years before we get answers to questions and see solutions to problems that justify offering this new technology to our patients.

As part of our Professional Relations team, these Refractive Surgery Counselors play a critical role in PCLI’s LASIK care. All refractive-surgery related calls coming into our 13 offices are automatically transferred to this group. Based in the Chehalis corporate office under the direction of Marlin Gimbel, Director of Professional Relations, this highly skilled team interacts with doctors and patients across 5 states and 3 time zones.

In addition to scheduling surgery appointments for your patients and helping them determine if their expectations are realistic, our Refractive Surgery Counselors ensure that the referral process flows seamlessly. With their experience, knowledge and wonderful customer-service skills, these counselors take pleasure in educating patients and answering their questions. They also enjoy the close communication with you and your and your office staff.