Skip to main content
. Author manuscript; available in PMC: 2022 May 24.
Published in final edited form as: J Biomech. 2021 Apr 8;121:110427. doi: 10.1016/j.jbiomech.2021.110427

Fig. 4.

Fig. 4.

Comparison of corneal natural frequencies (NF) among three protocols with different measurement areas (from 2.5 × 2.5 mm2 to 1 × 1 mm2) and time (from 28.6 s to 0.9 s) using the Single Degree of Freedom (SDOF) method (stimulation: 13 Pa, 10 Hz). (A) Bar plots (mean ± SD) for the measured natural frequencies for the three protocols on 20 eyes from 10 human subjects. (B) A comparison of residual error (mean vs. difference) shows good agreement among 3 protocols, indicating no distinct bias among protocols and similar 95% limits of agreements. The means ± 1.96 SD were −0.3 ± 4.1 Hz (Protocol 2 - Protocol 1) and - 0.2 ± 6.2 Hz (Protocol 3 - Protocol 1), respectively.