Wavefront-guided versus standard laser in situ keratomileusis to correct low to moderate myopia

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Abstract
To evaluate the 6-month refractive outcomes of wavefront-guided laser in situ keratomileusis (LASIK) (Zyoptix, Bausch & Lomb) versus standard LASIK (PlanoScan, Bausch & Lomb). Department of Ophthalmology, University Hospital Maastricht, Maastricht, The Netherlands. In a prospective randomized study, 12 patients with myopia had Zyoptix wavefront-guided LASIK in 1 eye and PlanoScan LASIK in the contralateral eye. The safety, efficacy, predictability, stability, optical zone size, and ablation depth were evaluated. The mean preoperative spherical equivalent (SE) of the subjective manifest refraction was −3.88 diopters (D) ± 1.92 (SD) (Zyoptix) and −4.35 ± 2.11 D (PlanoScan). Six months postoperatively, 8% of PlanoScan patients and 16% of Zyoptix patients gained at least 2 lines of best corrected visual acuity; the safety index was 1.12 in the Zyoptix group and 1.08 in the PlanoScan group. An SE of ±1.00 D and ±0.50 D was achieved by 100% and 92%, respectively, in both groups. There were 2 undercorrections in the Zyoptix group and 1 undercorrection in the PlanoScan group. In the Zyoptix group, 100% had a UCVA of 20/40 and 67% of 20/20 and in the PlanoScan group, 100% and 83%, respectively. The efficacy index was 0.87 and 0.93 in the Zyoptix group and PlanoScan group, respectively. The mean optical zone 6 months postoperatively was 6.16 ± 0.34 mm in the PlanoScan group and 6.23 ± 0.41 mm in the Zyoptix group (P = .67). The ablation depth per diopter of defocus equivalent was 13.5 ± 4.6 μm/D and 8.6 ± 4.4 μm/D, respectively (P = .01). An excellent safety index was achieved with the Zyoptix and PlanoScan treatments. The efficacy index was marginally lower for Zyoptix treatments as a result of 2 undercorrections. The ablation depth in the Zyoptix group per diopter of defocus equivalent was significantly lower than in the PlanoScan group. Further refinements in defining the ablation algorithms may increase the efficacy index.
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