1. Sonia Yoo, MD 1 Fernanda Piccoli, MD 1 Artur Schmitt, MD 1 Takeshi Ide, MD 1 Tsontcho Ianchulev, MD 2 Authors have no financial interest in this subject matter. 1- BASCOM PALMER EYE INSTITUTE 2- SAN FRANCISCO, CALIFORNIA

2. New Paradigm More than 1.000.000 refractive surgery cases per year; Ageing of “Baby Boomers”; Higher expectations regarding refractive cataract surgery outcomes.

3. Current Biometric Formulas Challenges Anatomic parameters: - axial length - keratometry Pre-refractive surgery measurements and history Theoretical non-optical formulas to derive optical estimate Current biometric formulas for IOL power estimation after LASIK surgery – low prediction

4. Intraoperative Optical Refractive Biometry - ORB Intraoperative aphakic auto-refraction for IOL estimation. (Ianchulev et al, Cataract Refract Surg. 2005 Aug;31(8):1530-6) No Axial Length measurement needed! No Keratometry needed! No Pre-Op History needed! ORB FORMULA

5. Purpose To figure out a predictive factor for IOL power estimation using the ORB methodology.

6. Patients and Methods 29 patients – 34 eyes 100% = myopic LASIK INTRAOPERATIVE PROCEDURE Phacoemulsification + cortex aspiration Discovisc ® (Alcon, Forthworth, Texas) in the bag APHAKIC AUTO-REFRACTION (Retinomax ®– Nikon, Tokyo, Japan) IOL IMPLANT – according to SRK/T and Holladay Formulas (IOLMaster®, Carl Zeiss Meditec, Jena, Germany)

7. Patients and Methods POST –OP MANIFEST SPHERICAL EQUIVALENT (1 month post-op) ADUSTED EMMETROPIC IOL POWER APHAKIC SHPERICAL EQUIVALENT REGRESSION ANALYSIS

8. Results AXIAL LENGTH Average: 24.440 mm (21.950mm – 30.670mm) APHAKIC SPHERICAL EQUIVALENT Average : +9.996 (+1.500 – +13.125) POWER IOL IMPLANTED (conventional formulas) Average: 20.909D (5.0D – 26.0D) MODEL IOL IMPLANTED IOL% SN60WF Alcon® 58.82% SN60AT Alcon® 26.47% LI61A0 Bausch & Lomb® 5.88% OTHERS8.82%

9. Results Correlation between intraoperative aphakic spherical equivalent and IOL power adjusted for emmetropia. (R 2 = 0.831) IOL ADJUSTED FOR EMMETROPIA

10. Results Predictive factor derived (PF) = 2.104±0.393 (p = 0.0045). n = 34 Type Eyes ORB ESTIMATED IOL POWER CONVENTIONAL ESTIMATED IOL POWER CORRELATION WITH ADJUSTED EMMETROPIC IOL POWER LASIK EYES R 2 = 0.889 p<0.0001 R 2 = 0.778 p<0.0001 ORB IOL = PF X APHAKIC SE

11. Conclusion ORB Clinical Utility A purely refractive methodology was derived to predict IOL power after refractive surgery (LASIK); The ORB method showed close correlation with conventional formulas; The ORB method showed close correlation with emmetropia; The ORB method appears to be sustainable over a large axial length range: 21.950mm – 30.670mm.

12. New Perspectives Improve accuracy and usability through: Intraoperative ACD Measurement; Intraoperative Wavefront Refractive Technology; Microscope Embedded Refractive Systems (Flow-through Retinoscopy); Optimized Tracking and Visual Axis Centration.