Accuracy of Haigis Formula Using Total Keratometry for IOL Power Calculation in Eyes with Previous Myopic and Hyperopic LASIK and PRK

Background: this retrospective study aimed to analyze the results of the combination of the Haigis formula and total keratometry (TK) in calculating the IOL power in eyes with previous corneal refractive surgery. Methods: the TK value provided by the IOL Master 700 (Carl Zeiss Meditec) was introduced into the Haigis formula; the mean prediction error (PE), mean absolute error (MAE), median absolute error (MedAE) and percentage of eyes with a PE within & PLUSMN;0.25 D, & PLUSMN;0.5 D, & PLUSMN;0.75 D and & PLUSMN;1.00 D were calculated. Results: ninety-three eyes of 93 patients with previous laser refractive surgery were evaluated. Two groups were defined: the Myopic Group included 51 previously myopic eyes and the Hyperopic Group included 42 previously hyperopic eyes. The mean PE in the Myopic Group was +0.09 & PLUSMN; 0.44 D and 76.47% of eyes had a PE within & PLUSMN;0.50 D. In the Hyperopic Group, the mean PE was -0.15 & PLUSMN; 0.46 D and 66.67% of eyes had a PE within & PLUSMN;0.50 D. Discussion: when compared to the results previously published with other formulas or methods, the Haigis formula combined with TK provided very accurate refractive outcomes for IOL power calculation in eyes with prior myopic and hyperopic corneal refractive surgery. In such eyes the results are similar to or better than those reported in previous studies.