Eyeworld

EW NEWS & OPINION 8 June 2016 the user whether or not an individ- ual calculation is within an internal boundary model," Dr. Hill said. Boundary models are a com- monly used tool in engineering, used to define the limits of accuracy for a specific type of calculation. Tracking outcomes A team of 24 volunteer ophthalmol- ogists in 13 countries from around the globe have gathered patient data and provided feedback on the RBF calculator over the past 6 years, Dr. Hill said. Haag-Streit (Köniz, Swit- zerland) helped fund work on the RBF calculator. Peter Maloney from MathWorks (Novi, Michigan) guided Dr. Hill and colleagues through model development; current core investigators include Douglas Koch, MD, and Li Wang, MD, Houston; Adi Abulafia, MD, Tel Aviv, Israel, and David Goldblum, Basel, Switzer- land. As part of the investigation within cataract surgery, the RBF cal- culator was retrospectively evaluated by 13 of the project's surgeons in 8 countries. Its use led to a weighted mean accuracy of 95%, which was an enormous improvement on the current mean accuracy of 78%, which is most commonly seen using the most popular theoretical for- mulas, Dr. Hill reported during the Charles Kelman Lecture at the 2015 American Academy of Ophthalmol- ogy annual meeting in Las Vegas. Results from a Haag-Streit study that Dr. Hill presented at the 2016 ASCRS•ASOA Symposium & Con- gress found that in a multicenter, prospective study of 459 eyes, 91% were within ±0.50 D of the intended target. The axial length of the eyes in this main group ranged from 20.97 mm to 29.10 mm. The calcula- tor reached the ±0.50 D target in 98.4% of patients with axial myopia (n=62; axial length greater than 25 mm) and 84.5% of patients with axial hyperopia (n=58; less than 22.5 axial length). A little more than 92% of normal eyes (n=347; axial length 22.5 mm to 25 mm) were within ±0.50 D. In a poster at the Association for Research in Vision and Ophthalmol- ogy (ARVO) annual meeting earlier this year, the RBF method also gave excellent outcomes for eyes with an axial length of 22.0 mm or lower compared with all other formulas. That research, led by Dr. Wang (Dr. Hill was one of several co-authors), evaluated 6 IOL power calculation formulas and included 77 eyes. "For the axial hyperope, as was found in the ARVO study, the RBF method gave very good accuracy, and we now have something addi- tional to use for these unusual eyes," Dr. Hill said. "The amazing ±0.50 D accuracy of greater than 98% [in the study presented at the ASCRS•ASOA Symposium & Congress] for the high axial myope was a surprise even for us." The next phase of the project will be an open-access, online cal- culation website that will make the methodology available to the entire ophthalmic community. "It's a fair statement that when completed, this will truly have been a worldwide collaborative effort," Dr. Hill said. This month, the calculator will become available as part of the LENSTAR EyeSuite software (Haag- Streit) as a regular menu item that a user can select, much in the same way a user selects other IOL power calculators, Dr. Hill said. The calculator is available on the ASCRS website. "ASCRS is excit- ed to make the latest IOL calculator available through our website, and we owe an incredible debt of grati- tude to Dr. Hill and his team for the work they've done to improve cat- aract surgery outcomes," said Don Bell, chief operating officer of ASCRS. EW Editors' note: Dr. Hill has financial interests with Alcon and Haag-Streit. Contact information Bell: dbell@ascrs.org Hill: hill@doctor-hill.com Taking continued from page 3 Multidimensional radial basis function surface response model showing an optimized relationship among IOL power, axial length, and ACD. Source: Warren Hill, MD Screenshot of the Hill RBF Calculator

• Cover