Comparison of visual and refractive results after transepithelial and mechanical photorefractive keratectomy in myopia.

Abstract

To compare postoperative visual outcomes and higher-order aberrations (HOAs) following transepithelial photorefractive keratectomy (t-PRK) and mechanical photorefractive keratectomy (m-PRK). The medical records of patients who underwent photorefractive keratectomy (PRK) were retrospectively evaluated. Forty-five patients were treated with m-PRK, and 45 were treated with t-PRK. Visual acuity, subjective manifest refraction, and corneal topography were analyzed before surgery and 12months after surgery for both groups. Total HOAs, spherical, coma, and trefoil aberrations were derived from topography data over the 6-mm corneal zone. In the m-PRK group, the mean preoperative spherical equivalence (SE) changed from -3.15±0.70 D preoperatively to -0.24±0.70 D 1year postoperatively. Likewise, SE decreased from -3.36±0.63 to -0.25±0.63 D in the t-PRK group 1year after the surgery. The number of eyes within±0.50 D of the target refraction was 89% for m-PRK and 87% for t-PRK groups (p=0.20). Eighty-four percentage of eyes in the t-PRK group and 80% of eyes in the m-PRK group showed an uncorrected distance visual acuity of 20/25 or better (p=0.24). Total HOAs, spherical aberration, coma, and trefoil aberrations increased in both groups after surgery, but no statistically significant differences were detected postoperatively among the corneal aberrations. t-PRK and m-PRK result in comparable refractive results for the correction of low and moderate myopia. Corneal aberrations induced by t-PRK and m-PRK were similar. Epithelial removal techniques do not affect visual, refractive results, or HOAs in PRK.