A Critical Assessment of Friedenwald’s Technique for Estimating the Coefficient of Rigidity of the Cornea

Table 2

Interoperator and intergroup differences in Ko estimations. 1 = Ko values estimated by operator 1. 2 = Ko values estimated by operator 2. Figures in parentheses are the number of individual cases where Ko values were not ≥0.11.

	Mean	Median	Mode	±sd	95% CI	Range
1 keratoconus (47)	0.019	0.018	0.025	0.008	0.017–0.021	0.009–0.035
1 post-CXL (37)	0.019	0.020	0.022	0.007	0.017–0.022	0.007–0.035
1 normal (17)	0.022	0.019	0.019	0.010	0.017–0.027	0.011–0.041
2 keratoconus (47)	0.021	0.017	0.021	0.014	0.024–0.032	0.007–0.088
2 post-CXL (37)	0.018	0.016	0.020	0.009	0.015–0.021	0.007–0.047
2 normal (17)	0.019	0.019	0.011	0.007	0.015–0.022	0.009–0.035