Visual and Refractive Outcomes After Sub-Bowman Keratomileusis and Transepithelial Photorefractive Keratectomy for Myopia

Purpose: To compare the visual and refractive outcomes of transepithelial photorefractive keratectomy (Trans-PRK) and sub-Bowman femtosecond-assisted laser in situ keratomileusis (SBK).

Setting: University hospital.

Design: Retrospective, comparative study.

Methods: Two hundred forty patients with myopia and myopic astigmatism underwent SBK (n=157) or Trans-PRK (n=83). The main outcome measures included manifest spherical equivalent refraction (MRSE), logarithm of the minimum angle of resolution uncorrected visual acuity (UCVA), and best-corrected visual acuity (BCVA), which were evaluated at 1 and 3 months postoperatively.

Results: The preoperative mean MRSE was -4.00±1.2 diopters (D) and -4.05±1.36 D (P=0.76) in Trans-PRK and SBK groups, respectively. There was a significant improvement in UCVA after Trans-PRK (1.29-0.00 at 1 month and -0.05 at 3 months; P<0.001 for both) and SBK (1.25 to -0.04 at 1 month and -0.05 at 3 months; P<0.001 for both). Both UCVA and BCVA were better after SBK compared with Trans-PRK at 1 month (-0.07 vs. -0.03; P<0.001) but not at 3 months (-0.08 vs. -0.07; P=0.223). The patients in Trans-PRK group were significantly more hyperopic compared with those in the SBK group at 1 month (0.11 vs. 0.04; P=0.034) and 3 months (0.11 vs. 0.04; P=0.011) postoperatively. Subgroup analysis showed that patients with myopia >3 diopters were more hyperopic at 1 month postoperatively as compared to patients with myopia of ≤3 diopters.

Conclusions: Both Trans-PRK and SBK are effective procedures to correct mild to moderate myopia and myopic astigmatism. Patients undergoing SBK experience quick visual recovery. Both procedures had no difference in visual outcomes 3 months postoperatively.