Factors Affecting the Accuracy of Intraocular Lens Power Calculation with Lenstar

This retrospective study was performed to compare refractive outcomes measured by conventional methods and by use of the Lenstar biometer and to investigate the factors affecting intraocular lens (IOL) power calculation with Lenstar with and without IOL-constant optimization. The study included 100 eyes of 86 patients who underwent cataract surgery. Corneal curvature was measured with a manual keratometer (MK), automated keratometer (AK), and the Lenstar biometer, and axial length (AL) was measured by A-scan and Lenstar. Mean numerical error (MNE) and mean absolute error (MAE) were compared between AK and MK with A-scan, and Lenstar with and without optimization. Factors affecting the accuracy of the IOL power calculation by use of Lenstar with and without optimization were analyzed. No significant differences were observed in the MNE or MAE among the devices. The proportion of MAE within 0.5 D was higher for Lenstar with optimization (62.7%) than without optimization (46.2%). The proportion of MAE within 0.5 D was 62% and 58% for MK and AK with A-scan, respectively. Without optimization, the MAE was smaller in eyes with ALs between 23 mm and 25 mm (p=0.03), whereas it was smaller at higher corneal powers when the IOL constant was optimized (>44 D, p=0.03). The IOL power calculations showed no significant differences among the devices, but the results of MAE within 0.5 D by use of Lenstar without optimization were worse than those of conventional methods. The AL influenced the accuracy of refractive outcomes determined by using Lenstar without optimization, and corneal curvature was shown to affect the accuracy of refractive measurements using Lenstar with optimization.