Clinical outcomes of laser in situ keratomileusis using combined topography and refractive wavefront treatments for myopic astigmatism
Accepted 28 March 2008.
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.
From the NewVision Clinics (Alpins, Stamatelatos), Cheltenham, and the University of Melbourne (Alpins), Melbourne, Australia
Dr. Alpins has a financial interest in the ASSORT program used for calculation of the treatment parameters and examination of outcomes. Mr. Stamatelatos is a consultant to ASSORT Pty Ltd.
Presented at the XXIV Congress of the European Society of Cataract & Refractive Surgeons, London, United Kingdom, September 2006.
AMO/Visx provided the 10 vision keycards required for the combined wavefront and topography values treatment.
Dimitri Chernyak, PhD, and George Dai, PhD, AMO/Visx Inc., set up the treatment profiles for the vector-planning group. Jenny Lee, MSc, BOptom, designed the protocol and analysis of the patient questionnaire. Gemma Walsh, BOptom, provided surgical assistance and implementation of the treatment profiles. James Ong, BSc Optom, PhD and Felicity Allen, PhD provided statistical analyses.
ABSTRACT