Table 3 Predictive refraction errors of all formulas.
New formula | Barrett universal II | Haigis | SRK/T | |
|---|---|---|---|---|
Mean prediction error | −0.04 | 0.02 | −0.06 | −0.07 |
Standard deviation | 0.36 | 0.40 | 0.44 | 0.47 |
Minimum | −0.99 | −0.93 | −1.32 | −1.46 |
Maximum | 0.94 | 1.12 | 1.57 | 1.60 |
Mean absolute error | 0.29 | 0.31 | 0.35 | 0.36 |
Median absolute error | 0.25 | 0.27 | 0.30** | 0.27** |
Percentage of errors within diopter range | ||||
±0.25D | 49.9% | 48.7% | 42.1% | 44.8% |
±0.50D | 84.3% | 78.0%* | 75.1%** | 73.9%** |
±0.75D | 96.1% | 93.2% | 92.9% | 87.8%* |
±1.00D | 100% | 99.1% | 97.9% | 96.1%** |
