High-order aberration changes after femtosecond LASIK surgery in patients with high myopia
Ziqing Feng, Qianru Wang, Chunyu Du, Fan Yang, Xue Li
Abstract
BACKGROUND: To investigate the relationship between high-order aberration (HOA) changes and RCST/CT (residual corneal stroma thickness/corneal thickness) after femtosecond LASIK surgery. METHODS: A total of 65 eyes from 39 patients with high myopia, who had femtosecond (FS) laser-assisted in situ keratomileusis (LASIK) surgery performed in our hospital, were included in this study. HOA and central corneal thickness were measured preoperatively and at 1 week, 1 month, and 3 months after FS-LASIK by Sirius Scheimpflug-Placido topography. Residual corneal stroma thickness (RCST) and ablation depth were measured during surgery. RESULTS: Horizontal coma (Z31), spherical aberration (Z40), second horizontal coma (Z51), second horizontal trefoil (Z53), pentafoil (Z55), second spherical aberration (Z60), and total HOAs were significantly increased at 1 week, 1 month, and 3 months after surgery compared with the preoperative values (P<0.05), but no significant differences were found in horizontal trefoil (Z33; P>0.05). Furthermore, Z31, Z40, and HOAs were significantly increased at 3 months post-surgery compared with the values at 1 week post-operation (P<0.05). Positive correlations were found between ablation depth and Z60 at 1 week and 1 month after surgery (r=0.291 and 0.337, respectively; P<0.05). Ablation depth was positively correlated with Z40 and Z60 at 3 months after surgery (r=0.439 and 0.336, respectively; P<0.05). The RCST/CT was negatively correlated with Z40, Z60, and HOAs at 3 months after surgery (r=-0.322, -0.412, and -0.321, respectively; P<0.05). There were no significant correlations between Zernike coefficients in terms of high-order aberration, HOAs, and RCST/CT at 1 week and 1 month post-surgery. CONCLUSIONS: Corneal HOAs in high myopia patients increased significantly after FS-LASIK surgery, and this was mainly observed as increases in coma and spherical aberration. The greater the ablation depth, the larger the influence on spherical aberrations. The greater the RCST/CT, the smaller the influence of HOAs on the cornea.