Accuracy of Multifocal IOL Power Calculation Using 2 Biometry Devices and Various IOL Power Calculation Formulas
Narrative Responses:
Purpose
To compare the postoperative refraction prediction error in patients implanted with multifocal intraocular lenses (IOLs) based on 2 different biometry devices and various IOL power calculation formulas.
Methods
Chart review of patients who had preoperative biometry with both IOLMaster 500 and Lenstar LS 900 and were implanted with a multifocal SN6AD1 (ReSTOR, Alcon) IOL. Postoperative manifest refraction was performed 1 month after the operation. Differences between predicted and actual postoperative refractions were calculated after optimization of the IOL constants for the SRK/T, HofferQ, Holladay I, Haigis, Holladay II and Barrett's universal formulas for each biometry. IOL calculations using the Olsen formula were done based on the Lenstar alone.
Results
Seventy three eyes of 48 patients were enrolled in this study. anterior chamber depth (ACD), average keratometry (K) and corneal astigmatism were closely correlated using the two biometry devices, however the Lenstar measurements were longer (AL), 0.023 mm, P<0.001; deeper (ACD) 0.071 mm, P<0.001; and flatter (K), 0.035D, P=0.03 than using the IOL Master. Nevertheless, the mean absolute error (MAE) and the standard deviation of the numerical error (NE-SD) were similar between the two devices using all formulas.
Conclusion
The Lenstar biometry measurements correlated well with those of the IOLMaster. There was no clinically significant difference in refraction prediction using all the combinations of the two biometry devices and the IOL power calculation formulas.