Comparison of Refractive Outcomes and Visual Quality Between Topography-Guided LASIK and Small Incision Lenticule Extraction: A 6-Month Prospective Study

Purpose: To compare the postoperative refractive outcomes and visual quality between topography-guided laser in situ keratomileusis (TG-LASIK) and small incision lenticule extraction (SMILE) over a 6-month follow-up. Patients and Methods: This study included 100 eyes of 50 patients, 50 eyes received TG-LASIK and 50 underwent SMILE. The outcomes measured included uncorrected distance visual acuity (UDVA), spherical equivalent (SEQ), cylinder, contrast sensitivity, and objective visual quality including objective scattering index (OSI), modulation transfer function (MTF) cutoff and Strehl Ratio (SR). Results: Baseline characteristics differed between groups, with the SMILE group being younger and demonstrating better preoperative UDVA and lower cylinder. At 6 months, 98% of TG-LASIK eyes and 100% of SMILE eyes achieved UDVA of 0.0 logMAR or better, with no significant difference between groups (P = 0.315). A significantly higher percentage of eyes in the TG-LASIK group achieved SEQ within ± 0.25 D (58% vs 36%, P = 0.028) and ± 0.50 D (88% vs 64%, P = 0.01). Despite treating significantly higher preoperative astigmatism, TG-LASIK achieved comparable correction accuracy to SMILE. Objective visual quality was similar between groups at 3 and 6 months; SMILE showed higher MTF cutoff at 1 month (P = 0.027). TG-LASIK demonstrated significantly higher contrast sensitivity at 6.0 c/d (P < 0.001) and 18.0 c/d (P < 0.001) at 6 months. Conclusion: Both TG-LASIK and SMILE are effective and safe for myopia and astigmatism correction. TG-LASIK demonstrated higher refractive precision and better contrast sensitivity at higher spatial frequencies compared to SMILE. Plain Language Summary: Conventional FS-LASIK and SMILE have been widely compared in previous studies. However, TG-LASIK differs from both procedures by using individualized corneal topography to guide customized ablation and is often applied in eyes with higher astigmatism or greater refractive complexity in routine practice. Whether this customized approach provides meaningful clinical advantages over SMILE under real-world conditions remains unclear. Both TG-LASIK and SMILE provided comparable visual acuity outcomes at 6 months after surgery. TG-LASIK achieved higher refractive precision, with a greater proportion of eyes reaching the intended spherical equivalent target. Although objective visual quality parameters were largely similar between the two groups, TG-LASIK was associated with better contrast sensitivity at higher spatial frequencies.