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

Table 3 Intraobserver repeatability outcomes for total corneal aberrations

Parameter	Operator	Mean ± SD (μm)	S_w (μm)	TRT (μm)	ICC (95% CI)
Total RMS	1st	1.01 ± 0.33	0.05	0.14	0.979 (0.969–0.986)
Total RMS	2nd	1.03 ± 0.33	0.07	0.19	0.957 (0.937–0.971)
Higher-order RMS	1st	0.62 ± 0.18	0.03	0.10	0.964 (0.947–0.976)
Higher-order RMS	2nd	0.63 ± 0.18	0.04	0.11	0.953 (0.932–0.968)
Coma Z (3, ± 1)	1st	0.35 ± 0.19	0.04	0.10	0.965 (0.949–0.977)
Coma Z (3, ± 1)	2nd	0.34 ± 0.20	0.04	0.12	0.955 (0.935–0.970)
Trefoil Z (3, ± 3)	1st	0.17 ± 0.09	0.05	0.14	0.722 (0.624–0.803)
Trefoil Z (3, ± 3)	2nd	0.19 ± 0.09	0.05	0.15	0.722 (0.625–0.803)
SA Z (4, 0)	1st	0.38 ± 0.12	0.02	0.06	0.967 (0.953–0.978)
SA Z (4, 0)	2nd	0.38 ± 0.12	0.02	0.07	0.964 (0.948–0.976)
Ast II Z (4, ± 2)	1st	0.14 ± 0.09	0.02	0.06	0.944 (0.919–0.962)
Ast II Z (4, ± 2)	2nd	0.14 ± 0.09	0.03	0.07	0.922 (0.888–0.947)

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