Ray-tracing–guided FS-LASIK Using Mi Optimized Strategies

Purpose: To evaluate the clinical outcomes of ray-tracing–guided femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK) in the patients with a difference of greater than 0.50 diopters (D) between subjective and wavefront refractions at the corneal plane. Methods: This retrospective study included 80 eyes (45 patients). The wavefront refraction was measured by InnovEyes sightmap (Alcon Laboratories, Inc). All patients underwent ray-tracing–guided FS-LASIK with the customized ablation profile following ray-tracing calculation adjusted by Mi optimized strategies. Visual acuity and refractive error were evaluated over 3 months, postoperatively. Results: The mean preoperative spherical equivalent (SEQ), subjective sphere diopter, and cylinder diopter of the included eyes were −6.82 ± 1.64, −6.15 ± 1.81, and −1.34 ± 1.01 D, respectively. At the 3-month postoperative follow-up visit, 98% of eyes achieved the uncorrected visual acuity (UDVA) of 20/20 and the mean UDVA was −0.08 ± 0.05 logarithm of the minimum angle of resolution. None of the treated eyes had a worse corrected distance visual acuity (CDVA). The R 2 value was 0.972 in the linear regression analysis of SEQ. The SEQ of 99% of eyes was within 1.00 D. The postoperative astigmatism in 88% of eyes was within 0.25 D. The mean difference vector was 0.04 D@81°. The arithmetic and geometric means of correction index were 1.08 and 1.05, respectively. Conclusions: This study demonstrated that ray-tracing–guided FS-LASIK offers superior outcomes in myopia correction. It highlighted that the surgery was also effective, safe, and predictable for the eyes with a difference of greater than 0.50 D between subjective and wavefront refractions, suggesting that more patients can benefit from this customized surgery.