Aspheric wavefront-guided versus wavefront-guided LASIK for myopic astigmatism with the Technolas 217z100 excimer laser.

Purpose: To compare clinical outcomes of wavefront-guided LASIK with and without aspheric compensation in myopic eyes.

Methods: In this observational, single-center study, 134 eyes were treated using an aspheric module in combination with wavefront-guided profiles (PTA-algorithm) and compared to 146 eyes treated with the predecessor wavefront-guided software (APT) that has no aspheric compensation. All treatment plans included the Rochester nomogram that accounts for the preoperative manifest refraction and interaction of higher order aberrations. Active eye-tracking (including cyclorotational movements) was utilized during photoablation.

Results: Results at the 3-month follow-up: 67 % of PTA-treated eyes and 39 % of APT-treated eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 or better. Change in mean higher order aberration root-mean-square (HOA RMS) after PTA treatments was not statistically significant (p = 0.18). The increase in HOA RMS after APT treatments was statistically significant (p = 0.003). Change in mean postop spherical aberration (SA) after PTA treatments was not statistically significant (p = 0.27). The change in SA after APT treatments was statistically significant (p = 0.001). In both cohorts, mean uncorrected low-contrast visual acuity was statistically not different to preoperative corrected values.

Conclusions: Adding an aspheric compensation to wavefront-guided myopic LASIK statistically improved clinical results in terms of visual acuity and refractive outcomes. Low-contrast visual acuity was not negatively affected in either group. While in APT-treated eyes mean HOA RMS and mean SA were significantly increased postoperatively, PTA-treated eyes showed neither induced HOA RMS nor induced SA.