Comparison Between the Wavefront-Optimized and Custom-Q Aspheric Ablation Profiles in Myopic Eyes With Two Different Q-targets: A Contralateral Eye Study

Abstract

PURPOSE: To compare two aspheric ablation profiles in myo- pic refractive surgery using different asphericity targets. METHODS: Patients underwent laser in situ keratomileu- sis (LASIK) with the WaveLight EX500 laser platform (Alcon, WaveLight Laser Technologie). Asymmetric surgery was per- formed, programming the wavefront-optimized (WFO) abla- tion profile in one eye and the custom-Q (CQ) profile in the contralateral eye. The patients were divided into two groups following a systematic randomization method. The Q-target programmed for the preoperative Q group was equal to the preoperative asphericity of the CQ profile, and for the -0.6 Q-target group, the Q-target was set to -0.6. RESULTS: The study included 100 patients (200 eyes). Both groups had comparable safety and efficacy indexes greater. The continuously evolving ophthalmic industry together with ongoing advances in biomedical research have made corneal refractive ablation surgery the technique of choice in low and medium myopia surgery. Several authors have reported high safety and efficacy indexes in both laser in situ ker- atomileusis (LASIK)1,2 and photorefractive keratec- tomy.3,4 However, the main challenge for clinicians and engineers is to control higher order aberrations than 1. A similar oblate shift in postoperative asphericity was seen in both groups regardless of the ablation profile and programmed Q-target. Asphericity was 0.33 ± 0.34 and 0.35 ± 0.29 (P = .18) in the preoperative Q group and 0.26 ± 0.28 and 0.26 ± 0.27 (P = .89) in the -0.6 Q-target group for WFO and CQ, respectively. A lower spherical aberration was found with CQ compared to WFO when the Q-target was set to -0.6: 0.211 ± 0.121 versus 0.144 ± 0.114 (P < .01). However, no statisti- cally significant differences were found when the preopera- tive Q-target was used. CONCLUSIONS: WFO and CQ treatments are similar in terms of refractive and visual outcomes. CQ offers greater control over the increase in positive spherical aberration after myo- pic refractive surgery, but it does not represent an advantage over WFO in the oblate shift in postoperative asphericity re- gardless of the Q-target programmed.