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

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.

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.

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 R² 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.

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.