Mean and standard deviations (SD) of five measurements of the distance (mm) that the keratoscopic astigmatic ruler was held from the corneal apex of five patients by two observers (observer 1 was a novice, observer 2 an experienced user)
| Observer 1 | Observer 2 | |||||||
|---|---|---|---|---|---|---|---|---|
| Patient | Mean | SD | Min–max | Mean | SD | Min–max | ||
| 1 | 20.8 | 1.3 | 20–23 | 19.5 | 1.5 | 17–21 | ||
| 2 | 20.6 | 1.1 | 19–22 | 20.3 | 0.5 | 20–21 | ||
| 3 | 19.8 | 1.3 | 18–21 | 19.8 | 0.6 | 19–20.5 | ||
| 4 | 21.0 | 1.0 | 20–22 | 20.0 | 1.0 | 19–21 | ||
| 5 | 19.8 | 1.8 | 17–22 | 20.3 | 0.5 | 20–21 | ||
| Overall | 20.4 | 1.3 | 20.0 | 0.9 | ||||
No significant difference between observers (p = 0.499, ANOVA)