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

Table 2 Intraobserver repeatability outcomes for posterior corneal aberrations

Parameter	Operator	Mean ± SD (μm)	S_w (μm)	TRT (μm)	ICC (95% CI)
Total RMS	1st	0.36 ± 0.11	0.02	0.06	0.957 (0.938–0.971)
Total RMS	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)
Higher-order RMS	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)
Coma Z (3, ± 1)	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)
Trefoil Z (3, ± 3)	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)
SA Z (4, 0)	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)
Ast II Z (4, ± 2)	2nd	0.02 ± 0.01	0.01	0.02	0.585 (0.461–0.697)

SD = standard deviation; S_w = within-subject standard deviation; TRT = test-retest repeatability (2.77 S_w); ICC = intraclass correlation coefficient; RMS = root mean square; SA = spherical aberration; Ast = astigmatism

ISSN: 2326-0254