Which laser is better for Wavefront LASIK?

Stanford Medicine’s LASIK study compares two lasers head-to-head

Stanford Medicine’s “Laser Comparison Study”: 50 patients (100 eyes) had Wavefront LASIK with the WaveLight Allegretto laser on one eye and the VISX CustomVue S4 IR laser on the other eye. In this scientifically-controlled study, the “5th generation iFS 150 Intralase femtosecond laser” (All-Laser LASIK) was also used for all eyes of both groups.

Results:
One year after LASIK, both wavefront lasers safely and effectively treated nearsightedness. However, several statistically-significant differences were identified:

1. Visual acuity results: 100% of the WaveLight Allegretto-treated eyes saw 20/20 compared to 96% of VISX-treated eyes.

2. High Order Aberrations: The Wavelight Allegretto laser significantly improved High-Order Aberrations (From 0.38µ down to 0.33µ), but the VISX CustomVue laser made them worse (From 0.37µ up to 0.40µ).

4. Predictability: After one year, the 100% of the Wavelight Allegretto-treated eyes were within ±0.50 D of the intended correction (plano) compared to 92% in the VISX group, which had more under-corrections and over-corrections.
5. Clarity: One of the most clinically-relevant findings was that patients reported more problems with their subjective “clarity at day” and “clarity at night” in the VISX-treated eyes compared to the Wavelight Allegretto-treated eyes in a direct side-by-side comparison.

REFERENCE/SCIENTIFIC ABSTRACT
1 Comparison of 2 wavefront-guided excimer lasers for myopic laser in situ keratomileusis: one-year results. Yu CQ, Manche E. J Cataract Refract Surg. 2014 Mar;40(3):412-22.

Purpose
To compare laser in situ keratomileusis (LASIK) outcomes between two wavefront-guided excimer laser systems in the treatment of myopia.
Setting
University eye clinic, Palo Alto, California, USA.
Design
Prospective comparative case series.
Methods
One eye of patients was treated with the Allegretto Wave Eye-Q system (small-spot scanning laser) and the fellow eye with the VISX Star Customvue S4 IR system (variable-spot scanning laser). Evaluations included measurement of uncorrected visual acuity, corrected visual acuity, and wavefront aberrometry.
Results
One hundred eyes (50 patients) were treated. The mean preoperative spherical equivalent (SE) refraction was −3.89 diopters (D) ± 1.67 (SD) and −4.18 ± 1.73 D in the small-spot scanning laser group and variable-spot scanning laser group, respectively. There were no significant differences in preoperative higher-order aberrations (HOAs) between the groups. Twelve months postoperatively, all eyes in the small-spot scanning laser group and 92% in the variable-spot scanning laser group were within ±0.50 D of the intended correction (P = .04). At that time, the small-spot scanning laser group had significantly less spherical aberration (0.12 versus 0.15) (P = .04) and significantly less mean total higher-order root mean square (0.33μm versus 0.40 μm) (P = .01). Subjectively, patients reported that the clarity of night and day vision was significantly better in the eye treated with the small-spot scanning laser.
Conclusions
The predictability and self-reported clarity of vision of wavefront-guided LASIK were better with the small-spot scanning laser (WaveLight Allegretto). Eyes treated with the small-spot scanning laser (WaveLight Allegretto) had significantly fewer HOAs.