ArticlePilot evaluation of refractive prediction errors associated with a new method for ray-tracing–based intraocular lens power calculationHirnschall, Nino MD, PhD, FEBO1; Buehren, Tobias PhD2; Trost, Micheal3; Findl, Oliver MD, MBA, FEBO1,* Author Information 1Vienna Institute for Research in Ocular Surgery, a Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria 2Carl Zeiss AG, Jena, Germany 3Carl Zeiss Meditec AG, Jena, Germany *Corresponding author: Oliver Findl, MD, MBA, FEBO, Hanusch Hospital, Heinrich-Collin-Strasse 30, 1140 Vienna, Austria. E-mail: [email protected] Submitted June 14, 2018; revised December 29, 2018; accepted January 16, 2019.Figure: No Caption available.First author: Nino Hirnschall, MD, PhD, FEBO Presented in part at the European Society of Cataract and Refractive Surgeons XXXV Congress, Lisbon, Portugal, October 2017. Journal of Cataract & Refractive Surgery: June 2019 - Volume 45 - Issue 6 - p 738-744 doi: 10.1016/j.jcrs.2019.01.023 Buy Metrics Abstract Purpose To investigate the accuracy of a new ray-tracing–based intraocular lens (IOL) power calculation method and to compare the outcomes with different IOL calculation formulas. Setting Hanusch Hospital, Vienna, Austria. Design Theoretical prospective monocentric study. Methods Monofocal aspheric plate haptic IOL (CT Asphina 409M/MP) implantation was performed in 40 cataractous eyes. At 1 month postoperatively, manifest refraction and optical coherence tomography–based biometry (IOLMaster 700) was conducted. The refractive spherical equivalent absolute error of the ray-tracing IOL power calculation method, based on individualized eye model data, a physical lens position predictor, retinal image quality metrics criteria for IOL power selection, and exact IOL design information was calculated and compared with the outcomes using the Barrett Universal II, Hill-RBF, SRK/T, and Haigis formulas. Results There was no significant difference in absolute error between ray tracing and the Barrett Universal II (0.37 diopter [D] ± 0.29 [SD]; P = .601) or Hill-RBF (0.39 ± 0.31 D; P = .170). However, the absolute error was significantly lower compared with the Haigis formula (0.42 ± 0.36 D; P = .029) and SRK/T (0.52 ± 0.39 D; P = .020). The refractive prediction of absolute error within ±0.25 D and within ±0.50 D ranged between 48% (ray tracing) and 25% (SRK/T), and between 80% (ray tracing) and 55% (SRK/T), respectively. Conclusions The new ray-tracing–based IOL power calculation method was an accurate procedure and showed promising preliminary results not only for the refractive outcome, but also for surgeon and patient education as well as the management of patient expectations. © 2019 by Lippincott Williams & Wilkins, Inc.
