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

Table 1 Intraobserver repeatability outcomes for anterior corneal aberrations

Parameter	Operator	Mean ± SD (μm)	S_w (μm)	TRT (μm)	ICC (95% CI)
Total RMS	1st	1.27 ± 0.42	0.05	0.14	0.985 (0.979–0.990)
Total RMS	2nd	1.29 ± 0.42	0.07	0.19	0.973 (0.961–0.982)
Higher-order RMS	1st	0.63 ± 0.18	0.03	0.10	0.964 (0.948–0.976)
Higher-order RMS	2nd	0.64 ± 0.18	0.04	0.10	0.960 (0.942–0.973)
Coma Z (3, ± 1)	1st	0.36 ± 0.20	0.04	0.10	0.967 (0.952–0.978)
Coma Z (3, ± 1)	2nd	0.36 ± 0.20	0.04	0.10	0.967 (0.952–0.978)
Trefoil Z (3, ± 3)	1st	0.17 ± 0.08	0.04	0.12	0.768 (0.682–0.838)
Trefoil Z (3, ± 3)	2nd	0.19 ± 0.09	0.05	0.13	0.763 (0.676–0.834)
SA Z (4, 0)	1st	0.40 ± 0.12	0.02	0.06	0.969 (0.955–0.980)
SA Z (4, 0)	2nd	0.40 ± 0.12	0.02	0.06	0.967 (0.953–0.978)
Ast II Z (4, ± 2)	1st	0.13 ± 0.09	0.02	0.06	0.951 (0.929–0.967)
Ast II Z (4, ± 2)	2nd	0.14 ± 0.09	0.02	0.07	0.931 (0.900–0.953)

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