Table 3
Analysis of variance of the means and standard deviations (SD) of multiple measurements of the six toric backcut contact lens blanks (buttons) using the Bausch & Lomb keratometer (B&L) and keratoscopic astigmatic ruler (KAR) (dioptres)
| KAR | B&L | ||||||
|---|---|---|---|---|---|---|---|
| Button | No | Mean | SD | No | Mean | SD | |
| 1 | 16 | 1.063 | 0.25 | 8 | 0.469 | 0.281 | |
| 2 | 16 | 2.375 | 0.619 | 8 | 1.531 | 0.198 | |
| 3 | 16 | 3.063 | 0.68 | 8 | 2.859 | 0.316 | |
| 4 | 16 | 4.188 | 0.75 | 8 | 3.656 | 0.332 | |
| 5 | 16 | 5.0 | 0.632 | 8 | 4.822 | 0.187 | |
| 6 | 16 | 5.875 | 0.5 | 8 | 5.584 | 0.473 | |
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Standard error of measurement: KAR = 0.59 D, B&L = 0.31 D.
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Intraclass correlation coefficient of reliability: KAR, R = 0.90 (95% CI >0.79), B&L, R = 0.97 (95% CI >0.94).
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Coefficient of variation: KAR = 0.405, B&L = 0.091. Coefficient of repeatability (95% CI test-retest): KAR = ±0.83 D, B&L = ±0.77 D.
