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Table 4 Subgroup analysis of the TMR group

From: Comparison of outcomes after topography-modified refraction versus wavefront-optimized versus manifest topography-guided LASIK

Parameter (Mean ± SD) Subgroup 1 (CA < RA) Subgroup 2 (CA > RA) P value
Preoperative
 BCVA (logMAR) −0.07 ± 0.07 −0.07 ± 0.06 .843
 Sphere (D) −2.55 ± 3.57 − 3.74 ± 1.75 .210
 Cylinder (RA; D) −1.48 ± 0.69 −1.00 ± 0.66 .009*
 MRSE (D) − 3.29 ± 3.69 − 4.24 ± 1.77 .330
 Flat keratometry (D) 42.95 ± 1.29 42.57 ± 1.20 .260
 Steep keratometry (D) 44.09 ± 1.45 43.99 ± 1.30 .780
 CA (D) 1.14 ± 0.62 1.42 ± 0.63 .111
 Magnitude difference between CA and RA (D) − 0.34 ± 019 0.43 ± 0.27 .000*
 Axis difference between CA and RA (°) 19.3 ± 11.1 25.4 ± 16.3 .230
Postoperative 3 months
 UDVA (logMAR) − 0.03 ± 0.11 −0.05 ± 0.11 .415
 UDVA (% of logMAR 0.0 or better) 68.8 82.6 .296
 Sphere (D) 0.14 ± 0.79 −0.01 ± 0.66 .440
 Cylinder (D) −0.52 ± 0.23 −0.44 ± 0.37 .297
 MRSE (D) −0.12 ± 0.80 −0.23 ± 0.67 .571
 MRSE (% of D within ±0.5) 68.8 68.1 .999
 MRSE (% of D within ±1.0) 93.8 91.3 .999
Change in astigmatism based on the Alpins method of vector analysis
 TIA 1.48 ± 0.69 1.09 ± 0.60 .027*
 SIA 1.52 ± 0.61 1.37 ± 0.78 .470
 DV 0.52 ± 0.23 0.46 ± 0.37 .568
 ME 0.04 ± 0.38 0.28 ± 0.38 .027*
 CI 1.16 ± 0.52 1.30 ± 0.51 .315
 IOS 0.47 ± 0.39 0.55 ± 0.54 .591
  1. TMR = topography-modified refraction; CA = corneal astigmatism; RA = refractive astigmatism; BCVA = best-corrected distance visual acuity; logMAR = logarithm of the minimal angle of resolution; MRSE = manifest refraction spherical equivalent; UDVA = uncorrected distance visual acuity; TIA = target-induced astigmatism; SIA = surgically-induced astigmatism; DV = difference vector; ME = magnitude of error; CI = correction index; IOS = index of success. *Statistically significant (P < .05)