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APHAKIC INTRAOPERATIVE OPTICAL REFRACTIVE BIOMETRY FOR INTRAOCULAR LENS (IOL) POWER CALCULATION AFTER REFRACTIVE SURGERY

APHAKIC INTRAOPERATIVE OPTICAL REFRACTIVE BIOMETRY FOR INTRAOCULAR LENS (IOL) POWER CALCULATION AFTER REFRACTIVE SURGERY. 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.

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APHAKIC INTRAOPERATIVE OPTICAL REFRACTIVE BIOMETRY FOR INTRAOCULAR LENS (IOL) POWER CALCULATION AFTER REFRACTIVE SURGERY

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  1. APHAKIC INTRAOPERATIVE OPTICAL REFRACTIVE BIOMETRY FOR INTRAOCULAR LENS (IOL) POWER CALCULATION AFTER REFRACTIVE SURGERY Sonia Yoo, MD1 Fernanda Piccoli, MD1 Artur Schmitt, MD1 Takeshi Ide, MD1 Tsontcho Ianchulev, MD2 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 ZeissMeditec, 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

  9. Results • Correlation between intraoperative aphakic spherical equivalent and IOL power adjusted for emmetropia. (R2 = 0.831) IOL ADJUSTED FOR EMMETROPIA

  10. Results • Predictive factor derived (PF) = 2.104±0.393 (p = 0.0045) • . 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.

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