New approach to IOL power calculation may improve refractive outcomes in second eye cataract surgery

In this retrospective, consecutive case series, the authors address the question of whether knowledge of the deviation of the first eye refractive error from that predicted by IOL power formula can be used to improve the refractive results of the second eye in patients undergoing bilateral, sequential phacoemulsification with IOL implantation.

The authors' method involves comparing the observed second eye one-month postoperative spherical equivalent refractive error to calculations of the hypothetical one-month postoperative spherical equivalent refractive error if the first eye error had been fully or partially incorporated into the choice of IOL power for the second eye. From there, they determined the optimal amount of partial adjustment. The investigators found that accounting for 50 percent of the observed error predicted refraction of the first eye reduced the error of predicted refraction in the second eye.

Among the 206 patients in this study, postoperative spherical equivalent refraction was within 0.5 D of predicted refraction in 66.5 percent of unadjusted second eyes, 67 percent of hypothetic fully adjusted second eyes and 74.3 percent of hypothetic partially adjusted second eyes.

Postoperative spherical equivalent refraction was within 1 D of predicted refraction in 90.3 percent of unadjusted second eyes, 90.8 percent of hypothetic fully adjusted second eyes and 93.7 percent of hypothetic partially adjusted second eyes, the authors reported.