Comparison of Toric Intraocular Lens Axis Accuracy between Optical Biometry and Dual Scheimpflug Topography.

PURPOSE: To evaluate the accuracy of toric intraocular lens (IOL) axis prediction between two preoperative measurement devices: the optical biometry (IOLMaster 500 or IOLMaster 700) and the dual Scheimpflug topography (Galilei G4).

METHODS

Medical records of 64 eyes from 44 patients who underwent phacoemulsification and posterior chamber toric IOL (Zeiss AT TORBI 709M) implantation between July 2017 and January 2022 were reviewed. All patients underwent preoperative evaluation by optical biometry (IOLMaster 500 or IOLMaster 700) and Galilei G4. The gold-standard axis that minimizes astigmatism was calculated by the online Toric Results Analyzer postoperatively and compared to the preoperative toric IOL axis calculated by the Z CALC Online IOL Calculator using parameters from either IOLMaster or Galilei G4. The axis error (AE) and the absolute AE (AAE) between the gold-standard axis and the preoperative calculated axis were analyzed to assess the accuracy of each device.

RESULTS

The mean flat keratometry and steep keratometry were 42.99 diopters (D) and 45.61 D, respectively, in IOLMaster, and 43.04 D and 45.51 D, respectively, in Galilei G4, which did not show any significant difference. The mean keratometric astigmatism was 2.62 D in IOLMaster and 2.46 D in Galilei G4, which also did not show any statistical difference. The keratometric astigmatism axis did not show any significant difference between IOLMaster and Galilei G4. The mean AE and AAE were 0.19° and 6.84°, respectively, by IOLMaster, and -0.80° and 7.98°, respectively, by Galilei G4. The AE and AAE by IOLMaster did not show any significant difference compared to those of Galilei G4 (p = 0.583, and p = 0.346, respectively).

CONCLUSIONS

This study suggests that the Galilei G4 demonstrated a similar level of accuracy to the IOLMaster in predicting the toric IOL axis, based on the gold-standard axis provided by the Toric Results Analyzer.