Reducing changes in spherical aberration and corneal asphericity in moderate and high myopic LASIK

Resumo

PURPOSE: To determine whether the spherical aberration (SA) and Q factor changes induced by laser treatment of moderate and high myopia can be reduced by using an aspheric customized algorithm. SETTING: Instituto Oftalmológico Amigó. Tenerife. Canary Islands. Spain. METHODS: A total of 194 eyes of myopic patients were divided into two groups: moderate myopia (M) (≥ 4 D and < 6 D) and high myopia (H) (> 6 D). One of two possible ablation profiles was used in each group: an optimized wavefront profile (WF) (M-WF: Spherical equivalent (SE) = −4.84 ± 0.56; H-WF: SE = −7.28 ± 0.86) and the F-CAT Q optimized type customized algorithm (FC) (M-FC: SE = −4.93 ± 0.6; H-FC: SE = −7.15 ± 1.01). Results were analyzed statistically three months after surgery. RESULTS: Predictability, safety and safety index were similar in all groups. Induced SA was: M-WF +0.17 ± 0.12, H-WF +0.27 ± 0.14, M-FC +0.02 ± 0.11, and H-FC +0.12 ± 0.14; and induced Q-factor was: M-WF +0.34 ± 0.2, H-WF +0.59 ± 0.27, M-FC +0.03 ± 0.3, and H-FC +0.32 ± 0.33, with statistically significant differences. There were no significant variations between groups in the remaining higher order aberrations. CONCLUSION: Using the F-CAT algorithm for ablation in moderate and high myopia yielded a significant reduction in induced SA and Q-factor with respect to the standard method, without altering procedural safety