Comparison of visual quality and optical zones after TransPRK, SMILE, and FS-LASIK myopia correction procedures

Abstract

Background

TransPRK, SMILE, and FS-LASIK are widely used surgical procedures for myopia correction, but differences in postoperative visual quality and optical zone design remain a subject of clinical interest. This study aimed to compare visual outcomes, higher-order aberrations (HOAs), contrast sensitivity, optical zone diameter, and corneal biomechanics among these three techniques.

Methods

In this prospective cohort study, 82 patients (164 eyes) with myopia were randomly assigned to undergo TransPRK (n = 56 eyes), SMILE (n = 52 eyes), or FS-LASIK (n = 56 eyes). All procedures were performed at a single center, and patients were followed for six months postoperatively. Outcome measures included uncorrected visual acuity (UCVA), HOAs, contrast sensitivity under both bright and dark conditions, optical zone diameter, refractive error, corneal biomechanical parameters (corneal hysteresis and resistance factor), and subjective symptoms such as nighttime glare and halos. Statistical analysis involved ANOVA and chi-square tests.

Results

At six months, all groups achieved comparable UCVA (≥ 96% achieving ≥ 1.0), but the TransPRK group demonstrated significantly lower total HOAs (0.25 ± 0.07 μm) and spherical aberrations (+ 0.05 ± 0.02 μm) than SMILE and FS-LASIK (P < 0.001). TransPRK also showed superior contrast sensitivity, particularly in low-light conditions (6 cpd: 1.05 ± 0.12 log units, P < 0.001). All techniques demonstrated comparable efficacy (indices > 1.0), with non-significant trends favoring SMILE for UCVA (98.08%) and TransPRK for refractive stability (-0.12 ± 0.25D; all P > 0.05). The SMILE group preserved the best corneal biomechanics (CH: 10.1 ± 1.1 mmHg; CRF: 10.5 ± 1.3 mmHg), while FS-LASIK had the highest incidence of nighttime glare (26.8%) and halos (23.2%) (P < 0.05).

Conclusions

TransPRK has good postoperative visual quality, but its advantages may be mediated by its larger optical zone design. In terms of night vision performance, SMILE surgery can effectively preserve the biomechanical properties of the cornea, while FS-LASIK achieved comparable 6-month acuity; we did not assess time-to-recovery. Selection of surgical modality should be individualized based on patient-specific anatomical and lifestyle factors.