Comparison of refractive outcomes using Scheimpflug Holladay equivalent keratometry or IOLMaster 700 keratometry for IOL power calculation

Purpose This study aims to compare postoperative refractive error results using Pentacam (Oculus Optikgeräte GmbH) Holladay equivalent keratometry readings (EKR) or IOLMaster 700 (Carl Zeiss Meditec AG) keratometry (K) values in IOL power calculation. Material and methods This retrospective study included 54 eyes of 31 patients who underwent cataract surgery. Preoperative biometric measurements of all patients were obtained using IOLMaster 700 followed by Pentacam measurements. IOLMaster 700 K measurements on horizontal (K1) and vertical (K2) axes and EKR measurements on 2 mm (EKR2mm), 3 mm (EKR3mm) and 4.5 mm (EKR4.5 mm) corneal zones were recorded. EKR4.5 mm value and IOLMaster 700 K values were used in Holladay-II, SRK/T, Haigis, and Hoffer-Q formulas to calculate predictive refractive error (PRE). Absolute refractive error (ARE) was calculated as the absolute difference between actual postoperative refractive error (APRE) and PRE values. Results Mean age was 72.2 ± 8.3 (51–87) years and mean IOL power was 21.5 ± 2.9 D (18–23 D). There was no significant difference between PRE values when IOLMaster 700 K measurements and EKR4.5 mm K measurements were used in Holladay-II, SRK/T, Haigis, and Hoffer-Q formulas ( p = 0.571, p = 0.833, p = 0.165, p = 0.347, respectively). There was no significant difference between APRE and ARE values ( p = 0.124). According to mean ARE results, the closest estimate was achieved when the IOLMaster 700 K values were used in the Holladay-II formula ( p = 0.271). Conclusion IOLMaster 700 K measurement and Pentacam EKR4.5 mm measurements can be used interchangeably. IOLMaster 700 K values yielded the most predictive measurement of the refractive result using the Holladay-II formula.