Spectacle plane add power of multifocal intraocular lenses according to effective lens position

Objective To evaluate the accuracy of predicting the spectacle plane add power of multifocal intraocular lenses (MIOLs) based on the effective lens position (ELP) using the Haigis formula. Design Retrospective cross-sectional study. Participants A total of 26 eyes from 18 consecutive patients who underwent phacoemulsification with Tecnis MIOL (Z*B00) implantation. Methods The postoperative spectacle plane add power of MIOLs was determined from the monocular defocus curve. The predicted add power error was defined as the difference between the predicted and postoperatively measured spectacle plane add power. The median absolute predicted add power error determined by the preoperatively estimated ELP using the Haigis formula was compared with power error calculated using the value presented by the manufacturer. The correlations among predicted add power error, postoperative spectacle plane add power, and back-calculated ELP were analyzed. Results The median absolute predicted add power error calculated using the Haigis formula (0.13 D) was significantly smaller than that calculated using the value presented by the manufacturer (0.26 D). The predicted add power error determined by the value presented by the manufacturer was negatively correlated with back-calculated ELP. The postoperative spectacle plane add power was negatively correlated with back-calculated ELP in the ZKB00 IOL (n = 21). Conclusions The predicted spectacle plane add power of MIOLs using the ELP of the Haigis formula was more accurate than that using the value presented by the manufacturer. The spectacle plane add power of MIOLs decreased as ELP increased.