Clinical Results Demostrate VISX CustomVue Wavefront Guided LASIK Outperforms Allegretto Wave Wavefront Optimized LASIK For Laser Eye Surgery. In my previous blog, we looked at the differences between wavefront guided LASIK and wavefront optimized LASIK.
Wavefront guided LASIK — the method used by VISX CustomVue excimer laser system — is based on using the optical fingerprint of the eye to measure and treat not only a patient’s nearsightedness, farsightedness, or astigmatism, but also the “higher order aberrations” of the eye as well — distortions in the optical system too complex to be treated by glasses or contact lenses. We discussed that spherical aberration was one of the several types of higher order aberrations that wavefront guided LASIK can correct using the CustomVue system from VISX.
By contrast, wavefront optimized LASIK — the method used by the Allegretto Wave Eye-Q excimer laser system — starts out by measuring the eye using a refraction, the “which is better one or two” test that you are probably familiar with. This refraction is entered into the laser and placed onto the eye during LASIK. Higher order aberrations, with one exception, simply are not addressed. The exception is that the wavefront optimized approach places a pre-programmed, non-customized, set of excimer laser pulses to counter-act any induction of spherical aberration (one type of higher order aberration) by the treatment itself. It does not customize the amount of spherical aberration treatment to the patient’s individual amount of pre-operative spherical aberration.
In my last blog, we discussed that the U.S. Navy, as part of their laser eye surgery program for Navy Top Gun Pilots, performed mathmatical modeling of wavefront guided versus wavefront optimized LASIK and found the wavefront guided approach to be optically superior on a theoretical level.
In this blog, we’ll look at the fact that clinical results confirm that wavefront guided LASIK using the VISX CustomVue system can outperform wavefront optimized LASIK using the Allegretto Wave Eye-Q system.
In August of 2011, Dr. Edward E. Manche of Standford University Department of Ophthalmology published the results of a Stanford University study comparing wavefront guided LASIK using the VISX CustomVue platform versus wavefront optimized LASIK using the Allegretto Wave Eye-Q 400-Hz excimer laser from Alcon Laboratories.
The Stanford study, to its credit, was a “contralateral study,” meaning one eye of each patient underwent wavefront guided LASIK and the other eye of the same patient underwent wavefront optimized LASIK. 110 eyes of 55 patients were studied in this contralateral approach.
Although results were good in both groups, they clearly were better in the wavefront guided eyes. While both groups of eyes had a slight increase in corneal aberrations after surgery, trefoil (an important type of higher order aberration) was reduced in the wavefront guided group but not in the wavefront optimized group. The eyes that underwent wavefront guided LASIK had essentially no residual refractive error (nearsightedness, farsightedness, or astigmatism), while the wavefront optimized group had a slight degree of residual post-operative nearsightedness (equal to 0.25 diopters) in the final results.
In general, the overall accuracy of results was higher in the wavefront guided eyes, with 87% of eyes reaching within 0.50 diopters of the intended correction versus 78% of the wavefront optimized eyes. The wavefront guided eyes showed superior uncorrected visual acuity (without glasses or contacts) results. By one week, for example, double the number of wavefront guided eyes saw better than 20/20 compared to wavefront optimized eyes. Similiarly, with 5% contrast actuity testing (a measurement of low light contrast resolution, a measure of visual quality), there were significantly greater gains in the wavefront guided eyes compared to the wavefront optimized eyes. Most important of all, of patients who indicated a preference between eyes, a majority of patients (65%) subjectively preferred the vision in their wavefront guided eye compared to their waveafront optimized eye at 12 months after surgery.
The Standford study was not the only study to demonstrate that wavefront guided LASIK with the VISX CustomVue excimer laser system can outperform wavefront optimized LASIK performed with the Alcon Allegretto Wavelight excimer laser system.
Jack Holladay, M.D., Clinical Professor of Ophthalmology at Baylor College of Medicine in Houston, presented results of a similar study in 2009. In Dr. Holladay’s study, 109 eyes underwent wavefront guided LASIK using the VISX CustomVue excimer laser vision correction system. These eyes were compared to 102 eyes that underwent wavefront optimized LASIK using the Allegretto Wavelight excimer laser vision correction system. Results showed, compared to wavefront optimized eyes, the wavefront guided eyes had significantly less induced overall higher order aberrations post-operatively, less induced spherical aberration, less induced trefoil, and less induced coma (yet another higher order aberration). There was, as might be expected from a non-customized approach, significantly more variability in the affect of wavefront optimized LASIK with the Allegretto system on treatment of higher order aberrations. In terms of induction of new higher order aberrations after surgery in the wavefront guided group of eyes, 12% of eyes were better, 76% were unchanged, and 12% had more higher order aberrations than they did pre-operatively. By contrast, in the wavefront optimized group, 8% were better, 51% were the same, and 41% were worse.
Dr. Holladay concluded that, “We have found that wavefront guided LASIK has the best chance of maintaining or improving higher order aberrations, and therefore has the best chance of providing optimal visual quality.”
In my own practice in Ventura, Santa Barbara, and San Luis Obispo, California, my strong preference is to perform wavefront guided laser eye surgery, whether it be LASIK or PRK, over either conventional surgery or wavefront optimized surgery. I find the data compelling that this approach offers my patients the state of the art in LASIK and PRK laser vision correction.
See Also
Fewer Higher Order Aberrations Yields Better Visual Performance
Study by Dr. Holladay of Baylor College of Medicine compares wavefront guided LASIK to wavefront optimized LASIK in terms of higher order aberrations
Wavefront-Guided LASIK for the Correction of Primary Myopia and Astigmatism: A Report by the American Academy of Ophthalmology
This synopsis prepared by the American Academy of Ophthalmology examines wavefront guided LASIK in comparison to other options for LASIK
Wavefront Guided Customized Corneal Ablation
The article examines wavefront guided laser vision correction
Wavefront Optimized Ablation Profiles: Theoretical Background
A article from the Swiss Institute of Technology, University of Zurich looks at the theory underlying wavefront optimized laser vision correction
Patient Information from VISX for CustomVue Laser Vision Correction
Patient information from the manufacturer of the VISC CustomVue system for wavefront guided laser vision correction
Allegretto Wave Eye-Q Information
Manufacturer’s information about the Allegretto Wave Eye-Q system for wavefront optimized laser vision correction