Modified Haigis Formula Effective Lens Position Equation for Ciliary Sulcus-Implanted Intraocular Lenses

To investigate the effect of a modified Haigis formula effective lens position equation on improving refractive outcomes in eyes with ciliary sulcus-implanted intraocular lenses (IOLs).

Retrospective cross-sectional study.

One hundred thirty-two eyes of 132 consecutive patients who underwent phacoemulsification with implantation of a ZA9003 (Abbott Medical Optics Inc, Santa Ana, California, USA; 69 eyes) or AR40e (Abbott Medical Optics Inc; 63 eyes) IOL in the ciliary sulcus were enrolled. The modified effective lens position (ELP) equation based on the corneal radius (CR) (ELP - β0 - β1 × CR, where β0 and β1 are parameters in the linear regression analysis) was obtained using linear regression analysis in each IOL group, and was applied to the other IOL group in order to evaluate its effect on refractive outcomes in an independent data set. The median absolute error (MedAE) was predicted using the modified effective lens position equation and was compared with that predicted using the adjusted IOL power.

The modified effective lens position equation was ELP + 11.662 - 1.6225 × CR in the ZA9003 group and ELP + 10.606 - 1.4817 × CR in the AR40e group. The MedAE that was predicted using the modified effective lens position equation (0.34 diopter [D] in the ZA9003 group and 0.42 D in the AR40e group) was significantly smaller than that predicted using the adjusted IOL power (0.47 D in the ZA9003 group and 0.66 D in the AR40e group) (P < .001 and P = .005, respectively).

IOL power calculation using the modified Haigis formula effective lens position equation improved refractive outcomes in eyes with sulcus-implanted IOLs.