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Table 2 Intraobserver repeatability outcomes for posterior corneal aberrations

From: Repeatability and reproducibility of corneal higher-order aberrations measurements after small incision lenticule extraction using the Scheimpflug-Placido topographer

Parameter Operator Mean ± SD (μm) Sw (μm) TRT (μm) ICC (95% CI)
Total RMS 1st 0.36 ± 0.11 0.02 0.06 0.957 (0.938–0.971)
2nd 0.36 ± 0.11 0.02 0.06 0.953 (0.932–0.968)
Higher-order RMS 1st 0.11 ± 0.03 0.02 0.07 0.597 (0.474–0.706)
2nd 0.11 ± 0.03 0.03 0.07 0.526 (0.394–0.649)
Coma Z (3, ± 1) 1st 0.03 ± 0.02 0.01 0.02 0.927 (0.895–0.950)
2nd 0.03 ± 0.02 0.01 0.02 0.892 (0.847–0.927)
Trefoil Z (3, ± 3) 1st 0.06 ± 0.03 0.03 0.08 0.432 (0.292–0.569)
2nd 0.06 ± 0.03 0.03 0.09 0.305 (0.161–0.455)
SA Z (4, 0) 1st 0.02 ± 0.02 0.01 0.02 0.810 (0.738–0.869)
2nd 0.02 ± 0.01 0.01 0.02 0.853 (0.794–0.899)
Ast II Z (4, ± 2) 1st 0.02 ± 0.01 0.01 0.02 0.634 (0.518–0.735)
2nd 0.02 ± 0.01 0.01 0.02 0.585 (0.461–0.697)
  1. SD = standard deviation; Sw = within-subject standard deviation; TRT = test-retest repeatability (2.77 Sw); ICC = intraclass correlation coefficient; RMS = root mean square; SA = spherical aberration; Ast = astigmatism