Table 2

 Agreement between tonometry methods: bias and 95% limits of agreement (or regression based equivalents)* either side of bias

Tonometry methodEstimated bias95% limits of agreement
OBF, ocular blood flow; NCT, non-contact tonometer.
*GAT observer 1 was the reference for comparison.
†Difference between methods related to mean of methods. Bias and 95% limits of agreement calculated from linear regression of method differences against method mean.
Tono-Pen (mm Hg)0.6Bias ±6.5
Goldmann observer 2 (mm Hg)†1.7–(0.12 × mean)Bias ±2.6
OBF (mm Hg)†6.0–(0.35 × mean)Bias ±5.4
NCT (mm Hg)†3.6–(0.17 × mean)Bias ±4.8