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Table 1 Patient characteristics

From: Impact of ablation ratio on 5-year postoperative posterior corneal stability after refractive surgery: SMILE and FS-LASIK

  SMILE group FS-LASIK group P value
Pre-operative data
 Patient number 43 32 N/A
 Study eye number 80 (38 left, 42 right) 63 (32 left, 31 right) N/A
 Sex (Male/Female) c 14/29 5/27 0.1
 Age (years) b 30 (25 ~ 32) 27 (23 ~ 32) 0.13
 Spherical refractive error (D) a −5.98 ± 1.52 −7.70 ± 2.28 < 0.01
 Cylindrical refractive error (D) b −0.50 (−1.00 ~ −0.25) −1.00 (−1.50 ~ −0.75) < 0.001
 Spherical equivalent (D) a −6.33 ± 1.56 −8.26 ± 2.39 < 0.001
 CDVA (logMAR) a −0.03 ± 0.05 −0.02 ± 0.04 < 0.01
 Axial length (mm) b 26.05 (25.48 ~ 26.76) 26.24 (25.50 ~ 27.25) 0.38
 Central corneal thickness (μm) b 561 (527 ~ 573) 545 (526 ~ 568) 0.28
Intra-operative data
 Cap/Flap diameter (mm) 7.5 8 N/A
 Cap/Flap thickness (μm) 100–110 100 N/A
 Lenticule thickness (SMILE, μm) or Ablation depth (FS-LASIK, μm) b 132 (104 ~ 144) 142 (128 ~ 158) < 0.001
  1. N/A= not applicable; CDVA=corrected distance visual acuity; logMAR=logarithm of the minimal angle of resolution; UDVA=uncorrected distance visual acuity; D=diopter; SMILE=small incision lenticule extraction; FS-LASIK=femtosecond laser-assisted in situ keratomileusis. Data are mean ± standard deviation or median and interquartile range for data that were normally or non-normally distributed. P values less than 0.05 were considered statistically significant.
  2. a Student’s t-test
  3. b Wilcoxon rank-sum test
  4. c Chi-squared test