Wavefront-guided LASIK better than conventional, but why?

Taking a counterpoint view, Jack T. Holladay, MD, MSEE, FACS, did not dispute that wavefront-guided treatments provide superior results. However, he maintained that the benefits achieved have nothing to do with wavefront guidance but rather reflect other wavefront-independent changes that have been made over time in the laser systems.

In support of the viewpoint that wavefront-guided ablation is the key to superior visual outcomes, Dr. Maloney compared results from FDA clinical trials for the Alcon, Bausch & Lomb, and VISX wavefront-guided systems to the last FDA approvals for conventional LASIK to treat low-to-moderate myopia.

Wavefront-guided results In comparing conventional and wavefront-guided LASIK performed with Alcon systems, the results consistently favored the wavefront-guided treatment whether analyzing proportions of patients achieving 20/20 uncorrected visual acuity (UCVA) (86% versus 64%), losing 2 lines of best spectacle-corrected visual acuity (BSCVA) (0% versus 1.2%), or complaining of night-driving difficulties (≤10% versus 30%).

For the Bausch & Lomb lasers, there was still a benefit for the wavefront treatment, although the difference at least in UCVA outcomes was less marked relative to the other manufacturers. In the Bausch & Lomb trials, 87% of patients treated with conventional LASIK achieved UCVA of 20/20 compared with 92% of patients undergoing wavefront-guided treatment. The rate of BSCVA loss of 2 lines was cut in half with the wavefront-guided approach from 1.1% to 0.6%, and about twice as many wavefront-guided patients compared with conventional LASIK patients reported improved night driving, 40% versus 22%.

Recognizing that the comparisons of wavefront-guided and conventional LASIK he made may be criticized on the basis that the results for the conventional treatments are from studies using outdated lasers that are 3 to 4 years old, Dr. Maloney presented results from a study comparing the conventional laser treatment using the best available laser against wavefront. That trial, undertaken by Capt. Steve Schallhorn, MD, was done using a VISX laser and included 50 patients undergoing wavefront treatment and 500 eyes in the conventional LASIK group treated with a 6.5-mm optical zone and 8-mm ablation zone.

Its results still favored the wavefront treatment. Rates of UCVA 20/20 or better were 98% for the wavefront treatment compared with 91% for the conventional laser, and while both groups showed a gain in BCVA at 3 months, the improvement was greater in the wavefront group. In addition, analyses of visual symptoms revealed a higher proportion of patients treated with conventional LASIK experienced an increase in halo complaints.