Refractive Prediction Accuracy Using Intraoperative Aberrometry versus Barrett True-K Formula Following Corneal Refractive Surgery

Purpose: To compare the refractive prediction accuracy of the Optiwave Refractive Analysis (ORA) SYSTEM with the Barrett True-K (BTK) formula in calculating intraocular lens (IOL) power in eyes that underwent cataract surgery after previous myopic photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK).

Methods: This retrospective study evaluated patients aged ≥22 years with prior myopic PRK or LASIK who underwent unilateral or bilateral cataract removal and monofocal IOL implantation using the ORA SYSTEM at 177 sites in the United States. Two datasets were analyzed: All Eyes (ie, all eligible eyes) and First Surgery Eyes (ie, each patient's first implanted eye). All Eyes were subgrouped by axial length (AL) and further analyzed. The main outcomes included paired differences in absolute prediction errors (APEs) between the ORA SYSTEM and BTK and differences in the proportion of eyes with APEs of ≤0.25 diopter (D) and ≤0.50 D.

Results: 1067 eyes were analyzed, including 897 First Surgery Eyes. Significantly higher proportions of All Eyes had APEs of ≤0.25 D (P = 0.0128) and ≤0.50 D (P < 0.0001) using the ORA SYSTEM than the BTK formula. Similarly, significantly higher proportions of First Surgery Eyes had APEs of ≤0.25 D (P = 0.0037) and ≤0.50 D (P = 0.0004) using the ORA SYSTEM than the BTK formula. In both datasets, mean (P < 0.0001) and median (P ≤0.0005) APEs were significantly lower with the ORA SYSTEM than with the BTK formula. AL did not affect the differences in prediction accuracy between these IOL power calculations.

Conclusion: In post-myopic PRK or LASIK eyes undergoing cataract surgery, the ORA SYSTEM provided significantly more accurate refractive predictability than the BTK formula, as determined by mean and median APE.