Clinical outcomes of mechanical and transepithelial photorefractive keratectomy in low myopia with a large ablation zone.

To evaluate the clinical outcomes, vector parameters, and aberrations between mechanical photorefractive keratectomy (PRK) and transepithelial PRK in eyes with low myopia. Yonsei University College of Medicine and Eyereum Eye Clinic, Seoul, Korea. Retrospective, comparative case series. Eighty-four eyes of 84 patients with low myopia (≤2.00 diopters) were treated with mechanical or transepithelial PRK (41 eyes and 43 eyes, respectively), with the application of a large optical zone (OZ). Visual acuity, manifest refraction, slitlamp evaluation, autokeratometry, corneal topography, and the evaluation of corneal wavefront aberrations were measured preoperatively and at 1, 3, and 6 months after surgery. The efficacy, predictability, vector parameters, corneal aberrations, and safety at 6 months after surgery were compared between the two treatment groups. The mean uncorrected distance visual acuity was comparable, at -0.13 ± 0.05 (SD) and -0.15 ± 0.05, in the mechanical and transepithelial PRK groups, respectively, at 6 months after surgery. The safety and efficacy indices, vector parameters, and aberrometric values were also comparable between the two groups. The OZ was large in both groups (7.09 ± 0.20 mm and 7.12 ± 0.27 mm in the mechanical PRK and transepithelial PRK groups, respectively), and showed no significant difference between groups. The corneal total root-mean-square higher-order aberrations and coma significantly reduced after treatment in both groups, and spherical aberrations significantly decreased after transepithelial PRK. Mechanical and transepithelial PRK with a large OZ provided effective and safe outcomes for the correction of low myopia without differences in visual acuity and refractive outcomes between procedures.

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