Laser Eye Surgery Articles & News

New research aims to help golfers focus on the key role of vision

CustomVue wavefront-guided technology - offers enhanced visual quality and happier patients

Capital News How To Guide June 24, 2007

Local Eye Laser Clinic Boasts State of the Art Technology

Considering Real-World Outcomes: Wavefront-Guided vs. Optimized Ablation

New research aims to help golfers focus on the key role of vision

Pro golfers such as Tiger Woods, Vijay Singh, Fred Funk and Zach Johnson among others have had lasik surgery to correct their eyesight to “Top Gun” sharpness so critical in the game of golf, especially when it comes to putting.

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CustomVue wavefront-guided technology - offers enhanced visual quality and happier patients

Dr. Jeffrey Machat, co-medical director of TLC Laser Eye Center in Toronto, Canada stated at a recent international presentation that since “we have switched over to 100 percent VISX CustomVue treatments, we have not had any patients with significant postoperative night glare or other quality - of vision problems” as he did with the Wavelight Allegretto optimized treatment and with conventional treatment.

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Local Eye Laser Clinic Boasts State of the Art Technology

FDA Approves VISX STAR S4 (TM) Excimer Laser System for Treatment of High Myopia With Astigmatism

The time has never been better to have laser eye correction and Kelowna Laser Vision is proud to have the leading technology in laser eye surgery. "I'm very excited about having this treatment option for my high myopic patients," said Joel Casey, KLV Optometrist. "The results from the clinical trial are outstanding. No high myopic results on any other laser platform are even close to the level of results that were achieved in this clinical trial. My patients will greatly benefit from this new technology."  

With this advancement in technology patients in the range of -14 for nearsightedness to +6 for farsightedness may be candidates for custom, wavefront laser treatment. Patients with high astigmatism can also be very effectively treated with a new alignment system called Iris Registration that “reads and locks on” to the anatomical features of the iris which are constant rather than the pupil which can change. Kelowna Laser Vision has been treating Kelowna and other B.C. residents successfully for over 12 years. They have a full surgical suite that allows them to also offer refractive lens exchange and monovision, something many other laser eye surgery clinics aren’t capable of. “We will always be at the leading edge of refractive eye care which means we can offer the treatments that are best for our patients”.

The treatments are so effective and reliable that recently two of the clinics doctors had laser eye surgery themselves. Both Dr. Jeff Chambers, one of the eye surgeons, and Joel Casey, the clinic Optometrist, had their procedures performed by Dr. Ron Baldassare at Kelowna Laser Vision over six months ago. The outcomes were fantastic, both can see better than 20/20. “It is truly incredible how much this procedure can change your life for the better, even just by reducing the hassle of glasses and contacts,“ said Dr. Chambers.

The other major recent advancement in laser eye surgery is the diagnostic technology. The WaveScan WaveFront® System, captures a comprehensive "fingerprint" of each eye, similar to a topographical map and generates an individualized treatment for each procedure. As shown in several clinical studies, “CustomVue”(TM) treatments have the potential to deliver better vision than is possible with contacts or glasses. “When you look at the diagnostic and treatment capabilities we have available to us now, it’s no wonder so many people are moving forward with this procedure,” commented Dr. Baldassare.

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Considering Real-World Outcomes: Wavefront-Guided vs. Optimized Ablation

After a poor initial correction with optimized, this patient was retreated with a CustomVue wavefront-guided ablation. These days, as refractive practitioners we no longer have to confine ourselves to the standard LASIK approach which has continued to evolve over the past decade. We all look to find the technology that can provide our patients with the best outcomes. Two such promising approaches that we have tried in our practice are the wavefront-guided technique, with the VISX Star S4 (AMO, Santa Ana, California) and the wavefront-optimized approach, with the Allegretto Wave (WaveLight Laser Technologie AG, Erlangen, Germany). These approaches augment conventional LASIK very differently. The wavefront-guided technique allows surgeons to measure and treat lower- and higher-order aberrations in the eye with the aid of an aberrometer. With this method each patient receives a unique custom treatment.

On the other hand, the WaveLight-optimized approach does not measure aberrations. Instead, with this approach a standardized spherical aberration coefficient is utilized on all patients to compensate for induced spherical aberration.

This is accomplished through placement of additional laser pulses in the corneal periphery. We all understand that conventional LASIK is able to effectively deal with lower order terms. The problem has been that conventional LASIK induces higher order aberrations, most importantly spherical aberration, and secondarily coma.

Therefore, it stands to reason that an ablation profile which compensates for spherical aberration would be better than a standard ablation profile. But how does a wavefront-optimized approach compare to a customized approach in the real world?

A real world view

In our office we've done thousands of wavefront optimized and wavefront-guided procedures. For a time, we used to market conventional LASIK, wavefront-optimized, and wavefront-guided LASIK to our patients in a three-tiered approach. Our standard program was the Planoscan with the Bausch & Lomb 217 (Rochester, New York). The intermediate-priced approach, which we called "Prolate," was the WaveLight-optimized technique. CustomVue was our premier approach.

Our clinical results mirrored our pricing system both in terms of safety (loss of BCVA, night glare) and visual and refractive results. The Prolate approach worked for most patients. It was easy and less time consuming than our Custom approach, with substantially better outcomes than the conventional approach, but the Prolate clinical results paled in comparison to our CustomVue outcomes.

While 20-30% of our Prolate eyes improved BCVA, versus only 2-3% of our conventional PlanoScan eyes, over 50% of our CustomVue patients gained BCVA. Since the WaveLight Prolate program does not compensate for induced spherical aberration above -6.00 diopters, we suspected that it would be only these patients who would complain of night glare. But such was not the case.

Even at low levels of myopia we were surprised to find the occasional patient complaining of difficulty driving at night after optimized ablations. We attributed this to increases in other higher order aberrations, and we certainly tried to avoid the wavefront-optimized program for all severe myopes (>-6.00D). Similarly, the surprises with loss of best corrected vision with Prolate occurred only sporadically. This was a finding we never observed with CustomVue.

The enhancement issue

Another point of comparison was that our enhancement rate with the WaveLight-optimized approach was more than double what it was with the CustomVue wavefront-guided approach. Furthermore, we found that the only way to make our WaveLight-optimized patients truly happy was to perform a CustomVue enhancement on top of their Prolate ablation.

A good example of wavefront-guided fixing a Prolate treatment problem involves a patient with induced coma. Both eyes received primary Prolate treatment that resulted in induced coma, trefoil, and spherical aberration, as well as residual refractive error. In the right eye, the Prolate treatment increased the patient's coma value from .30 to .44. After retreatment with CustomVue, it was reduced to .23. BCVA in the right eye had dropped to 20/25+1 from 20/20 pre-op with Prolate, but was restored back to 20/20 after retreatment. Similarly, in the left eye coma increased from .19 with Prolate to .40, and was then reduced to .23 after CustomVue retreatment. (See figure above)

Trefoil increased from .04 to .34 with Prolate and decreased with CustomVue retreatment to .19. Even spherical aberration increased in this patient from treatment with the WaveLight - despite a pre-op myopia level less than -6.00 diopters - from .04 OD and .07 OS to .16 OD and .31 OS.

Unfortunately, while the majority of my Allegretto patients were truly happy with their results, we had no way to know who the subset of unhappy patients would be pre-operatively. There were a few indicators of which patients would not fare as well with the WaveLight-optimized procedure, such as those with negative spherical aberration (which is approximately 10% of the population), those with significant coma, and those with very low RMS values pre-op.

Ultimately, my partners and I decided to switch exclusively to the CustomVue wavefront-guided approach. We found that we had more referrals from those patients who had undergone the CustomVue procedure, and that over time other doctors disproportionately started to refer their patients specifically for our custom approach as well.

Overall, after more than a decade of evolution in laser vision correction it is apparent from our results that the WaveLight-optimized approach, while a significant step forward compared to conventional ablation profiles, still is not comparable to custom ablation profiles. Without question, customized ablations are the best means to not only avoid problems but also obtain superior outcomes.

Dr. Machat is co-medical director of TLC Laser Eye Center in Toronto, Ontario, Canada.

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