Clinical outcomes of laser in situ keratomileusis using combined topography and refractive wavefront treatments for myopic astigmatism

Purpose

To evaluate outcomes of laser in situ keratomileusis (LASIK) guided by wavefront alone versus wavefront plus topographic data.

Setting

NewVision Clinics, Cheltenham, Australia.

Methods

Twenty-one eyes (14 patients) were distributed into 2 groups in a prospective double-masked study. One group was treated by wavefront parameters alone (WF, n = 11), and the other, by wavefront combined with topography values (WF&VP, n = 10) using vector planning. All treatments were performed using Visx Star S4 CustomVue software. In the WF&VP group, the treatment profile was calculated using simulated keratometry readings from the Humphrey Atlas topography and 2nd-order Zernike coefficients defocus 4 and astigmatism 3 and 5 from the WaveScan wavefront display of the entire eye.

Results

Mean corneal astigmatism preoperatively was 1.07 diopters (D) ± 0.54 (SD) in the WF group and 1.50 ± 0.87 D in the WF&VP group. At 6 months, it was 0.67 ± 0.57 D (39% reduction) and 0.83 ± 0.55 D (44% reduction), respectively. The WF&VP group had a greater reduction in horizontal coma. The mean gain in low-contrast visual acuity under mesopic conditions was 0.06 in the WF group and 0.11 in the WF&VP group and the mean gain in high-contrast visual acuity, 0.02 and 0.05, respectively. Two patients reported a change in the preferred eye postoperatively to the eye treated using vector planning. No result demonstrated statistical significance.

Conclusion

The WF&VP group had greater reduction in corneal astigmatism and better visual outcomes under mesopic conditions than the WF group and equivalent higher-order aberrations.