Wavefront-guided LASIK really is better, experts say

February 15, 2005

All three of us now have personalized nomograms and strongly prefer to use customized ablation whenever possible.

Is wavefront-guided LASIK better than conventional LASIK? Some of our colleagues have suggested that the difference is all hype.

The best measure of the accuracy of a refractive procedure is the spread, or standard deviation, of the results. In clinical trials of wavefront-guided LASIK with these three lasers, there is a standard deviation of about 0.3 D for the postoperative spherical equivalent. This is within the standard deviation for refraction and is better than the standard deviation for conventional LASIK with each of these systems.

Limiting the induction of higher-order aberrations reduces the likelihood of night-vision complaints and loss of best spectacle-corrected acuity (BSCVA). Across all three clinical trials for wavefront-guided LASIK, only one eye lost 2 lines of BSCVA and no eyes lost more than 2 lines. Subjective responses from patients in wavefront clinical trials also support this assertion.

Each manufacturer has asked slightly different survey questions, but the results all indicate improved night vision as a marker for an improved aberration profile.

There is no doubt in our minds that wavefront-guided LASIK for low to moderate myopia is significantly superior to conventional LASIK in terms of quality of vision, refractive accuracy, and safety.

Of course, there has been some hype around wavefront-guided LASIK. The original promise that it would reduce preoperative higher-order aberrations has not yet been fully realized. We are still inducing higher-order aberrations, albeit to a lesser degree. In a way, this is not surprising. The correction of myopia requires flattening of the central cornea to produce an oblate cornea, which induces some positive spherical aberration. What is remarkable is that the induced aberrations are so low. And even with the induction of some aberrations, a substantial percentage (44% to 66%) of wavefront-treated patients do experience improvements in BSCVA compared with before LASIK.

Getting the best results The data presented above are from clinical trials, which means they represent the "out-of- the-box" outcomes. Individual surgeons may be able to obtain even better results by fine-tuning their nomograms to adjust for the peculiarities of individual techniques and operating environments. All three of us now have personalized nomograms and strongly prefer to use customized ablation whenever possible.