Vector analysis of astigmatic correction after single-step transepithelial photorefractive keratectomy and femtosecond-assisted laser in-situ keratomileusis for low to moderate myopic astigmatism

Abstract

Purpose: This study aimed to evaluate the outcomes of astigmatic correction by single-step transepithelial photorefractive keratectomy (TransPRK) and femtosecond-assisted laser in-situ keratomileusis (Femto-LASIK) surgeries. Methods: A total of 218 subjects received TransPRK or Femto-LASIK surgery for the treatment of myopia and astigmatism (−2.25 to −0.25 D). Refraction errors and uncorrected (UDVA) and corrected distance visual acuity (CDVA) were examined before and at 3 months after surgery. Astigmatism changes were assessed by vector analysis. Results: Preoperative parameters of the TransPRK group were similar to the Femto-LASIK group. UDVA and CDVA at 3 months were similar between both groups. Manifest refraction (MR) spherical equivalent in the TransPRK group (0 ± 0.20 D) was slightly lower compared with the Femto-LASIK group at 3 months (0.11 ± 0.25 D, P = 0.001). MR cylinder was -0.06 ± 0.19 D in the TransPRK group and -0.02 ± 0.15 D in the Femto-LASIK group at 3 months (P = 0.135). The index of success (IS) was 0.15 ± 0.36 in the TransPRK group and 0.06 ± 0.17 in the Femto-LASIK group (P = 0.125). The correction index (CI) was 1.03 ± 0.19 in the TransPRK group and 1.01 ± 0.11 in the Femto-LASIK group (P = 0.815). Conclusion: For low to moderate myopic astigmatism, TransPRK provided a comparable astigmatic treatment effect as Femto-LASIK. Myopic astigmatism was both slightly overcorrected after TransPRK and Femto-LASIK surgeries.

Keywords

• astigmatism
• keratorefractive surgery
• low to moderate myopia
• vector analysis