EyeWorld India December 2018 Issue

65 EWAP DEVICES December 2018 much. For patients who are 25.5 to 27 mm, the optimized axial length formula by Wang-Koch using the Holladay 1 is extremely accurate, but the Barrett Universal and the Hill-RBF are equally as ac- curate,” she said. For post-refractive surgery patients, Dr. Koch likes the Barrett True K formula, OCT-based, and Haigis. “When we have refractive data, we like the Masket formula as well,” he added. Dr. Yeu said that the Barrett True K formula, which is now part of the ASCRS post-refractive calcu- lator, has taken her predictability of a 0.5 D spherical equivalent to 86–88%. “It is better now than it used to be because if you look at the ASCRS calculator, while you do not need to fill in every cell because the different cells exist for various devices, it certainly is helpful. The ones I do fill in every time are the four single millim- eter zones of the Atlas (Carl Zeiss Meditec, Jena, Germany), as well as the K value of my LENSTAR (Haag-Streit, Koniz, Switzerland). I don’t use historical information. I use the basic biometry informa- tion from my LENSTAR. With that information alone, the average predicted IOL power is extremely accurate using the Barrett True K as well as the other information populated by the ASCRS post- refractive calculator. If you have access to intraoperative aberrome- try, which now exists only in ORA (Alcon, Fort Worth, Texas), use it,” she advised. The future Dr. Koch thinks that ray-tracing formulas are where cataract sur- gery is headed. “We have to figure out a better way to determine the effective lens position, and I’m becoming more and more of a skeptic about our ability to predict that. I think there is going to be a certain number of eyes in which the effective lens position is going to surprise us and where our ac- curacy is not going to be as good as we want. While we need better approaches for estimating effec- tive lens position, we’re still going to rely postoperatively on corneal refractive surgery and the ability to modify IOLs postoperatively, such as those we have seen with RxSight (Aliso Viejo, California) and Perfect Lens (Irvine, Califor- nia).” EWAP Optical biometry and inbuilt IOL formulas for any eye status Use Total Corneal Refractive Power (TCRP) keratometry to account for individual total corneal astigmatism of every patient and select suitable aspheric, toric and multifocal IOL candidates more confidently. Perform swift IOL calculations using the inbuilt IOL Calculator, avoid manual transcription errors and optimize your personal constants. Included: Barrett IOL formulas and customized formulas for post-corneal refractive patients Pentacam ® AXL The All-in-One Unit! OCULUS Asia Ltd. Hong Kong Tel. +852 2987 1050 • Fax +852 2987 1090 www.oculus.de • info@oculus.hk Reference 1. Gökce SE, et al. Intraocular lens power calculations in short eyes us- ing 7 formulas. J Cataract Refract Surg . 2017;43:892–897. Editors’ note: Dr. Yeu has financial interests with Alcon, Johnson & John- son Vision (Santa Ana, California), and Carl Zeiss Meditec. Dr. Koch has financial interests with Carl Zeiss Meditec and Perfect Lens. Contact information Koch: dkoch@bcm.edu Yeu: eyeu@vec2020.com