ABSTRACT
PURPOSE: To evaluate prediction accuracy of formulas included in the ESCRS-Online-IOL-Calculator using standard keratometry (K) or total keratometry (TK). SETTING: Hospital-based academic practice. DESIGN: Retrospective case-series. METHODS: Participants: 523 cataract patients (523 eyes). Outcome Measures: trimmed-means of the spherical equivalent prediction error (SEQ-PE, trueness), precision and absolute SEQ-PE (accuracy) of all seven formulas available on the ESCRS-Online-IOL-Calculator as well as the mean (Mean-All) and median (Median-All) of the predicted SEQ refraction of all formulas. Sub-group analyses evaluated the effect of axial length on formula accuracy. RESULTS: Trimmed-mean SEQ-PE range of all formulas varied from -0.075 to +0.071D for K-based and from -0.003 to +0.147D for TK-based calculations, with TK-based being more hyperopic in all formulas (p<0.001). Precision ranged from 0.210 to 0.244D for both K-based and TK-based calculations. Absolute SEQ-PE ranged from 0.211 to 0.239D for K-based and from 0.218 to 0.255D for TK-based calculations. All formulas, including Mean-All and Median-All, showed high accuracy with 84-90% of eyes having SEQ-PEs within 0.50D.Myopic trimmed-mean SEQ-PEs significantly different from zero were observed in long eyes for Pearl DGS (-0.110D, p=0.005), Hill RBF (-0.120D, p<0.001) and Hoffer QST (-0.143D, p=0.001), and in short eyes for EVO 2.0 (-0.252D, p=0.001), Kane (-0.264D, p=0.001), Hoffer QST (-0.302D, p<0.001), Mean-All (-0.122D, p=0.038) and Median-All (-0.125D, p=0.043). CONCLUSION: Prediction accuracy of all ESCRS IOL Calculator formulas was high and globally comparable. TK-based calculations did not increase prediction accuracy and tended towards hyperopia. Observations indicating formula superiority in long and short eyes merit further evaluation.
ABSTRACT
PURPOSE: To compare intraocular lens (IOL) power prediction accuracy of the Eyestar 900 (EyeS900) and the IOLMaster 700 (IOLM700) based on estimated and measured posterior corneal power. DESIGN: Retrospective, interinstrument reliability study. METHODS: Setting: Institutional. PARTICIPANTS: Two hundred twenty-five eyes of 225 cataract surgery patients. MEASUREMENTS: Patients underwent measurements by both devices preoperatively. MAIN OUTCOME MEASURES: Spherical Equivalent Prediction Error (SEQ-PE), spread of the SEQ-PE (precision) and the absolute SEQ-PE (accuracy) of each device using Barrett Universal II (BUII) formula with either estimated posterior keratometry (E-PK) or measured posterior keratometry (M-PK). RESULTS: Trimmed mean SEQ-PEs of EyeS900 E-PK, EyeS900 M-PK, IOLM700 E-PK, and IOLM700 M-PK were 0.03, 0.08, 0.02, and 0.09 D, respectively with no significant differences between EyeS900 E-PK and IOLM700 E-PK (P = 0.31) as well as between EyeS900 M-PK and IOLM700 M-PK (P = 0.31). Statistically significant SEQ-PE differences were found when E-PK and M-PK were compared, regardless of the device used, showing hyperopic SEQ-PE in M-PK calculations. Excellent correlation and agreement in SEQ-PE were found between the devices for both E-PK (P < 0.001, r = 0.848, mean bias: +0.01 D, 95% LOA of -0.32 to +0.34 D) and M-PK (P < 0.001, r = 0.776, mean bias: -0.01 D, 95% LOA of -0.42 to +0.39 D). No significant differences were found comparing absolute SEQ-PE and precision of the devices. CONCLUSION: The Eyestar 900 and the IOLMaster 700 show comparable IOL power prediction accuracy by the BUII formula using either estimated or measured posterior keratometry. An adjusted lens factor may be required for BUII when utilizing measured posterior keratometry in both devices.
