Abstract
Purpose :
It is currently inconclusive how the newer generation intraocular lens (IOL) power formulas perform on eyes undergoing combined phacovitrectomy. We performed a retrospective, clinical study to assess the refractive accuracy of 4 newer generation formulas in eyes which underwent combined phacovitrectomy.
Methods :
Preoperative optical biometry and postoperative outcomes were obtained from 61 eyes which underwent combined phacovitrectomy from 2017 to 2020 at the Johns Hopkins Wilmer Eye Institute. Inclusion criteria were postoperative best corrected visual acuity of 20/40 or better within 6 months and IOL implantation in the capsular bag. Exclusion criteria include eyes with any history of ocular surgeries, intraoperative complications, or evidence of corneal pathology. The Barrett Universal II, Kane, EVO v2.0, and Hill-RBF v3.0 were compared for their accuracy in predicting postoperative spherical equivalents (SE). Correlations between biometric parameters and errors were also assessed. A Wilcoxon rank sum test and Pearson’s correlation coefficient were used for statistical analyses.
Results :
Errors ranged from -2.36 to 2.97 diopters (D), mean absolute errors (MAE) ranged from 0.47 to 0.50 D, and median absolute errors (MedAE) ranged from 0.28 to 0.34 D. The Barrett formula had the lowest mean error (-0.035), MAE (0.469) and MedAE (0.275). The Barrett formula also had the highest percentage of eyes with predicted error within ±0.25 D (49.2%) and ±0.5 D (72.1%). Based on the MedAE, however, the Barrett formula had a comparable accuracy to other formulas (p ranged from 0.46-0.75). No other pairwise comparisons resulted in statistically significant differences. The anterior chamber depth (ACD) was found to have a weak negative correlation with error for all formulas. (correlation coefficients: -0.29 to -0.32, p: 0.011 to 0.026) The axial length (AL), mean keratometry (Km), and IOL power did not have a statistically significant correlation with error for all formulas.
Conclusions :
All 4 newer generation formulas had a comparable accuracy in predicting refractive outcomes in eyes undergoing combined phacovitrectomy. Because the ACD had a statistically significant correlation with error in all formulas, this may serve as a target for improving the accuracy of newer formulas.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.