Eyeworld

22 | EYEWORLD | JANUARY/FEBRUARY 2020 ASCRS NEWS different axial eye lengths, in post-refractive surgery eyes, and with different IOLs. 1–5 In this paper, Darcy et al. provide a performance comparison of available IOL formulas in a large U.K. dataset. What stands out most from this work is that the new Kane formula, based on theoretical optics and artificial intelligence, provided the most accurate refractive outcomes across all axial eye lengths and with the four IOLs included in the study. The importance of this result is that access to a single, ubiquitously accurate formula could simplify the busy cata- ract surgeon's IOL selection process. A major strength of this study was its large-scale nature. The dataset used in the IOL formula analysis included >10,000 eyes over a 10-year period, obtained from two large NHS trusts. Of note, there were large numbers of all axial eye lengths including short (<22 mm) and long (>26 mm) eyes, strengthening the accuracy of the analysis at these eye lengths. Further, there were strong numbers of each of the four IOLs used. third generation formulas with lower MAEs (p<0.05). When analyzing the axial length subgroups, the Kane formula also had the lowest mean ab- solute prediction error at all axial lengths: short (p<0.01), medium (p<0.001), and long (p<0.05 Barrett; p<0.001 other formulas). In addition, the formulas were compared among the IOL types used. The Kane formula had the lowest mean absolute prediction error for the SA60AT (p<0.001), C-Flex (p<0.001), and Akreos Adapt (p<0.05); however, the Barrett (p=0.4) and Hill 2.0 (p=0.06) formulas resulted in a lower mean absolute prediction error for the Superflex IOL. Discussion Accurate postoperative refractive outcomes are fundamental to surgical success in modern cataract surgery. Refractive accuracy continues to improve with advancements in IOL technol- ogies, surgical techniques, and newer generation IOL formulas. Choosing which IOL formula to use is not always a straightforward process, however, as previous comparison studies have shown varying superiority of the formulas at continued from page 21 References 1. Abulafia A, et al. Intraocular lens power calculation for eyes with an axial length greater than 26.0 mm: comparison of formulas and methods. J Cataract Refract Surg. 2015;41:548–56. 2. Hamill EB, et al. Intraocular lens power calculations in eyes with previous hyperopic laser in situ keratomileusis or photorefractive keratectomy. J Cataract Refract Surg. 2017;43:189–194. 3. Gökce SE, et al. Intraocular lens power calculations in short eyes using 7 formulas. J Cataract Refract Surg. 2017;43:892–897. 4. Rong X, et al. Intraocular lens power calculation in eyes with extreme myopia: Comparison of Barrett Universal II, Haigis, and Olsen formulas. J Cataract Refract Surg. 2019;45:732–737. 5. Wang Q, et al. Meta-analysis of accuracy of intraocular lens power calculation formulas in short eyes. Clin Exp Ophthalmol. 2018;46:356–363. Dr. Jack Kane met with the University of Iowa ophthalmology residents over Skype to discuss his article. From left: Tony Chung, MD, Karam Alawa, MD, Dr. Kane on screen, Caroline Wilson, MD, and Austin Fox, MD Source: University of Iowa continued on page 24

• Blank Page
• Blank Page (1)