Evaluation of the accuracy of the Haigis-L, Barrett True-K formulas for calculating intraocular lens power in eyes that had previously undergone corneal refractive surgery

Aim This study aimed to evaluate and compare the accuracy of the Haigis-L, Barrett True-K formulas in predicting intraocular lens power for eyes that have undergone corneal refractive surgery. Patients and methods A retrospective study was conducted on 134 eyes with a history of corneal refractive surgery. The predictive accuracy of the Haigis-L and Barrett True-K formulas was analyzed and the prediction error for each formula was assessed. The postoperative refractive outcomes were compared to the target refraction to determine the more accurate formula. Statistical analysis used are statistical tests, including the unpaired Student’s t test, Mann–Whitney test, and χ 2 or Fisher’s exact test, were employed for data analysis. Results The target refraction with the Haigis-L formula ranged from −1.75 to 0.15 D (mean: −0.49±0.53 D), while for the Barrett True-K formula, it ranged from −1.88 to 0.5 D (mean: −0.68±0.57 D). Three months postphacoemulsification, the refraction ranged from −2 to 0.5 D (mean: −0.66±0.67 D). There was no significant difference between the Barrett True-K target refraction and postoperative refraction at 3 months. However, the Haigis-L target refraction was significantly higher compared to postoperative refraction at 3 months ( P =0.037). Conclusions The comparison between the Barret True-K formula and postphacoemulsification refraction demonstrated an insignificant difference, suggesting that the Barret True-K formula provides a reliable estimation of target refraction, aligning closely with actual postoperative measurements. In contrast, the Haigis-L formula yielded significantly higher target refraction compared to postphacoemulsification refraction.