Prospective, Randomized, Contralateral Eye Comparison of Functional Optical Zone, and Visual Quality After SMILE and FS-LASIK for High Myopia

PURPOSE: To compare the functional optical zone (FOZ) and visual quality after small-incision lenticule extraction (SMILE) and femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK) in correcting high myopia. METHODS: Ninety-two eyes of 46 high myopic patients with the same programmed optical zone (POZ) received SMILE in one eye and FS-LASIK in the contralateral eye. FOZ was calculated using a refractive power method. The decentration, visual outcomes, wavefront aberrations, contrast sensitivity, and quality of vision (QoV) questionnaire were analyzed at 6 months postoperatively. RESULTS: The postoperative visual and refractive outcomes were comparable between SMILE and FS-LASIK. The FOZ for SMILE (5.62 ± 0.31 mm) was larger than for FS-LASIK (5.35 ± 0.28 mm; P < 0.001). Moreover, the total decentration for SMILE (0.29 ± 0.14 mm) was greater than in FS-LASIK (0.22 ± 0.11 mm; P < 0.001). The induced change in spherical aberration was less for SMILE than for FS-LASIK (P < 0.001). There was better contrast sensitivity under the mesopic condition with glare for SMILE than for FS-LASIK (P = 0.024). However, no significant difference was found in QoV scores between the two groups. CONCLUSIONS: SMILE created a larger FOZ and greater decentration than FS-LASIK when the same POZ was designed in high myopia. Objective and subjective visual symptoms were comparable between SMILE and FS-LASIK. TRANSLATIONAL RELEVANCE: The differences in FOZ and decentration between SMILE and FS-LASIK have little effect on vision outcomes. Surgeons should consider the FOZ and decentration in surgical options in high myopia.