Comparison of Kane and Barrett Toric Formulas using Different Keratometric Parameters

Purpose . To compare Kane and Barrett toric formulas using different keratometric parameters. Material and methods . The study included 31 patients (31 eyes) who underwent phacoemulsification (PE) with implantation of the Clareon® Toric CNW0T2-T9 TIOL (Alcon, USA). Biometry was performed on IOL-Master 700 (Carl Zeiss, Germany), and keratopography on CASIA OCT SS-1000 device (Tomey, Japan). TIOL was calculated using Kane and Barrett toric calculator (BTC) formulas using various keratometric data. Mean centroid error (MCE) and mean absolute centroid error (MACE), frequency of target cylinder hitting within ±0.25, ±0.50, ±0.75, ±1.00, and over 1.00 D were compared. Results . The lowest MCE (0.19 ± 0.92 D) and MACE (0.82 ± 0.43 D), as well as a higher frequency of target cylinder hitting (90%) were shown by Kane formula when IOL-Master keratometric values were used. BTC was slightly less accurate — MCE (0.27 ± 0.96 D), MACE (0.86 ± 0.48 D), the frequency of target cylinder hitting within ±1.00 D was 84% when anterior corneal surface data by IOL-Master and the posterior corneal values by CASIA topographer were used. Conclusion . Kane formula demonstrates the best refractive results for TIOL calculation using standard IOL-Master keratometry data.