Comparison of Optical Zone Decentration Following FS-LIKE and SMI-LIKE for Correcting Hyperopia

To investigate optical zone decentration following femtosecond laser-assisted lenticule intrastromal keratoplasty (FS-LIKE) or small incision lenticule intrastromal keratoplasty (SMI-LIKE) for correcting hyperopia.

This study analyzed decentration values obtained from optical coherence tomography (OCT) and tangential topography difference maps of 23 eyes (18 patients) undergoing FS-LIKE (n = 12) or SMI-LIKE (n = 11) via the concentric centration method. Total higher order aberrations (HOAs) and component aberrations were measured preoperatively and 6 months postoperatively.

The mean optical zone decentration was 0.27 ± 0.08 and 0.39 ± 0.16 mm for the FS-LIKE and SMI-LIKE groups, respectively (P = .039). A significant difference was noted in lenticule decentration between the two groups (0.18 vs 0.37 mm), whereas no significant difference was observed in stromal bed (pocket) decentration between the two groups (0.10 vs 0.12 mm). Six months after surgery, the spherical equivalent showed a reduction of 6.14 ± 2.44 and 6.10 ± 1.79 diopters (D) for the two groups, respectively (P = .971), whereas the surgically induced astigmatism was 0.68 ± 0.49 and 1.56 ± 0.78 D for the two groups, respectively (P = .004). Furthermore, induction of HOAs in the SMI-LIKE group was significantly larger than that in the FS-LIKE group (P = .013).

FS-LIKE can yield improved treatment centration and less induction of total HOAs. [.