Accuracy of Contemporary Intraocular Lens Calculation Formulas Based on Swept-Source OCT Biometry in Eyes with Capsular Tension Ring

Objectives: To compare the refractive prediction accuracy of contemporary intraocular lens (IOL) calculation formulas based on swept-source optical coherence tomography (OCT) biometry in cataract surgery with capsular tension ring (CTR) implantation, and to assess for systematic postoperative refractive tendencies. Materials and Methods: This retrospective study included 98 eyes of 92 patients who underwent phacoemulsification with in-the-bag IOL and CTR implantation. Preoperative biometry utilized swept-source OCT (ARGOS, Alcon). Refractive prediction accuracy was evaluated for the Barrett Universal II, Haigis, SRK/T, and Holladay II formulas. Main outcomes included mean prediction error, mean absolute error (MAE), median absolute error (MedAE), and percentages of eyes within ±0.25, ±0.50, and ±1.00 diopter (D). Results: The mean age was 73.0±8.1 years, and the mean axial length was 23.03±1.04 mm. Barrett Universal II yielded the lowest MAE and MedAE (0.36±0.34 D and 0.24 D, respectively), followed by Holladay II (0.40±0.32 D and 0.30 D). Higher MAE was observed with SRK/T (0.45±0.37 D) and Haigis (0.54±0.45 D). MAE differed significantly among the formulas (p<0.001), with pairwise comparisons showing that Barrett Universal II and Holladay II performed similarly (p>0.05) and better than both Haigis and SRK/T (all p≤0.003). The highest percentage of eyes within ±0.25 D was observed with Barrett Universal II (52.04%), whereas Holladay II showed the highest percentage within ±0.50 D (69.39%), and the two formulas tied within the ±1.00 D range (both 92.86%). Prediction errors were positive for all formulas, indicating a mild hyperopic shift. Conclusion: In eyes undergoing cataract surgery with CTR implantation, Barrett Universal II and Holladay II showed more favorable refractive prediction accuracy than Haigis and SRK/T. A mild hyperopic shift was observed across all formulas. This finding may be clinically relevant when selecting the target refraction or IOL power in these eyes.