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M. M. Merchea, G. Youssefi; Advanced Ablation Algorithms for the Elimination of Surgically Induced Spherical Aberration. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5341.
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© ARVO (1962-2015); The Authors (2016-present)
To compare visual acuity, wavefront error and corneal asphericity results of the new Zyoptix Aspheric algorithm with the standard Zyoptix Tissue Saving algorithm in a randomized clinical trial.
Subjects were enrolled into a randomized prospective study comparing Zyoptix Tissue Saving (non-wavefront guided) (Control) and Zyoptix Aspheric (Test) LASIK treatment of myopia and myopic astigmatism. Subjects were followed for a 3-month period and post-op metrics including logMAR visual acuity and wavefront aberrations were collected. Post-op corneal asphericity was also compared between the groups.
All eyes in both treatment groups were within +/- 1.00D, and 77.9% of Test eyes, and 83.1% of Control eyes had uncorrected high-contrast visual acuity of 20/20 or better. Low contrast VA was significantly better by 1 or more lines, in the Test eyes (46.5%) versus Control eyes (27.4%). The Test eyes had significantly less induced spherical aberration (SA) (0.04um) vs. the Control (0.22um), as well as lower 3rd order and overall HORMS (p<0.001). The Test group demonstrated induced spherical aberration of 0.05um or less for -1.00D through -5.00D of treatment, or an increase of no greater than 0.10um for up to -9.00D of treatment. The Control treatment was associated with a statistically significantly greater change in postop corneal asphericity (Q=0.686) than the Test treatment (Q=0.277) (p<0.0001).
The Zyoptix Aspheric algorithm was not associated with clinically significant surgically induced spherical aberration postoperatively. The Zyoptix Aspheric algorithm preserved preop corneal asphericity better than the standard algorithm.
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